add callbacks to denoising step (#5427)

* draft1

* update

* style

* move to the end of loop

* update

* update callbak_on_step_end_inputs

* Revert "update"

This reverts commit 5f9b153183d0cde3b850f14024d2e37ae8c19576.

* Revert "update callbak_on_step_end_inputs"

This reverts commit 44889f4dabad95b7ebb330faa5f1955b5d008c88.

* update

* update test required_optional_params

* remove self.lora_scale

* img2img

* inpaint

* Apply suggestions from code review
Co-authored-by: Patrick von Platen <patrick.v.platen@gmail.com>

* fix

* apply feedbacks on img2img + inpaint: keep only important pipeline attributes

* depth

* pix2pix

* make _callback_tensor_inputs an class variable so that we can use it for testing

* add a basic tst for callback

* add a read-only tensor input timesteps + fix tests

* add second test for callback cfg

* sdxl

* sdxl img2img

* sdxl inpaint

* kandinsky prior

* kandinsky decoder

* kandinsky img2img + combined

* kandinsky inpaint

* fix copies

* fix

* consistent default inputs

* fix copies

* wuerstchen_prior prior

* test_wuerstchen_decoder + fix test for prior

* wuerstchen_combined pipeline + skip tests

* skip test for kandinsky combined

* lcm

* remove timesteps etc

* add doc string

* copies

* Update src/diffusers/pipelines/stable_diffusion/pipeline_stable_diffusion.py
Co-authored-by: Sayak Paul <spsayakpaul@gmail.com>

* Update src/diffusers/pipelines/stable_diffusion/pipeline_stable_diffusion.py
Co-authored-by: Sayak Paul <spsayakpaul@gmail.com>

* make style and improve tests

* up

* up

* fix more

* fix cfg test

* tests for callbacks

* fix for real

* update

* lcm img2img

* add doc

* add doc page to index

---------
Co-authored-by: yiyixuxu <yixu310@gmail,com>
Co-authored-by: Patrick von Platen <patrick.v.platen@gmail.com>
Co-authored-by: Sayak Paul <spsayakpaul@gmail.com>
Co-authored-by: Dhruv Nair <dhruv.nair@gmail.com>

src/diffusers/pipelines/stable_diffusion/pipeline_stable_diffusion_instruct_pix2pix.py

@@ -13,7 +13,7 @@
 # limitations under the License.
 
 import inspect
-from typing import Callable, List, Optional, Union
+from typing import Callable, Dict, List, Optional, Union
 
 import numpy as np
 import PIL.Image
@@ -92,6 +92,7 @@ class StableDiffusionInstructPix2PixPipeline(DiffusionPipeline, TextualInversion
     model_cpu_offload_seq = "text_encoder->unet->vae"
     _optional_components = ["safety_checker", "feature_extractor"]
     _exclude_from_cpu_offload = ["safety_checker"]
+    _callback_tensor_inputs = ["latents", "prompt_embeds", "image_latents"]
 
     def __init__(
         self,
@@ -152,8 +153,9 @@ class StableDiffusionInstructPix2PixPipeline(DiffusionPipeline, TextualInversion
         negative_prompt_embeds: Optional[torch.FloatTensor] = None,
         output_type: Optional[str] = "pil",
         return_dict: bool = True,
-        callback: Optional[Callable[[int, int, torch.FloatTensor], None]] = None,
-        callback_steps: int = 1,
+        callback_on_step_end: Optional[Callable[[int, int, Dict], None]] = None,
+        callback_on_step_end_tensor_inputs: List[str] = ["latents"],
+        **kwargs,
     ):
         r"""
         The call function to the pipeline for generation.
@@ -201,12 +203,15 @@ class StableDiffusionInstructPix2PixPipeline(DiffusionPipeline, TextualInversion
             return_dict (`bool`, *optional*, defaults to `True`):
                 Whether or not to return a [`~pipelines.stable_diffusion.StableDiffusionPipelineOutput`] instead of a
                 plain tuple.
-            callback (`Callable`, *optional*):
-                A function that calls every `callback_steps` steps during inference. The function is called with the
-                following arguments: `callback(step: int, timestep: int, latents: torch.FloatTensor)`.
-            callback_steps (`int`, *optional*, defaults to 1):
-                The frequency at which the `callback` function is called. If not specified, the callback is called at
-                every step.
+            callback_on_step_end (`Callable`, *optional*):
+                A function that calls at the end of each denoising steps during the inference. The function is called
+                with the following arguments: `callback_on_step_end(self: DiffusionPipeline, step: int, timestep: int,
+                callback_kwargs: Dict)`. `callback_kwargs` will include a list of all tensors as specified by
+                `callback_on_step_end_tensor_inputs`.
+            callback_on_step_end_tensor_inputs (`List`, *optional*):
+                The list of tensor inputs for the `callback_on_step_end` function. The tensors specified in the list
+                will be passed as `callback_kwargs` argument. You will only be able to include variables listed in the
+                `._callback_tensor_inputs` attribute of your pipeine class.
 
         Examples:
 
@@ -244,8 +249,34 @@ class StableDiffusionInstructPix2PixPipeline(DiffusionPipeline, TextualInversion
                 second element is a list of `bool`s indicating whether the corresponding generated image contains
                 "not-safe-for-work" (nsfw) content.
         """
+
+        callback = kwargs.pop("callback", None)
+        callback_steps = kwargs.pop("callback_steps", None)
+
+        if callback is not None:
+            deprecate(
+                "callback",
+                "1.0.0",
+                "Passing `callback` as an input argument to `__call__` is deprecated, consider use `callback_on_step_end`",
+            )
+        if callback_steps is not None:
+            deprecate(
+                "callback_steps",
+                "1.0.0",
+                "Passing `callback_steps` as an input argument to `__call__` is deprecated, consider use `callback_on_step_end`",
+            )
+
         # 0. Check inputs
-        self.check_inputs(prompt, callback_steps, negative_prompt, prompt_embeds, negative_prompt_embeds)
+        self.check_inputs(
+            prompt,
+            callback_steps,
+            negative_prompt,
+            prompt_embeds,
+            negative_prompt_embeds,
+            callback_on_step_end_tensor_inputs,
+        )
+        self._guidance_scale = guidance_scale
+        self._image_guidance_scale = image_guidance_scale
 
         if image is None:
             raise ValueError("`image` input cannot be undefined.")
@@ -259,10 +290,6 @@ class StableDiffusionInstructPix2PixPipeline(DiffusionPipeline, TextualInversion
             batch_size = prompt_embeds.shape[0]
 
         device = self._execution_device
-        # here `guidance_scale` is defined analog to the guidance weight `w` of equation (2)
-        # of the Imagen paper: https://arxiv.org/pdf/2205.11487.pdf . `guidance_scale = 1`
-        # corresponds to doing no classifier free guidance.
-        do_classifier_free_guidance = guidance_scale > 1.0 and image_guidance_scale >= 1.0
         # check if scheduler is in sigmas space
         scheduler_is_in_sigma_space = hasattr(self.scheduler, "sigmas")
 
@@ -271,7 +298,7 @@ class StableDiffusionInstructPix2PixPipeline(DiffusionPipeline, TextualInversion
             prompt,
             device,
             num_images_per_prompt,
-            do_classifier_free_guidance,
+            self.do_classifier_free_guidance,
             negative_prompt,
             prompt_embeds=prompt_embeds,
             negative_prompt_embeds=negative_prompt_embeds,
@@ -291,7 +318,7 @@ class StableDiffusionInstructPix2PixPipeline(DiffusionPipeline, TextualInversion
             num_images_per_prompt,
             prompt_embeds.dtype,
             device,
-            do_classifier_free_guidance,
+            self.do_classifier_free_guidance,
             generator,
         )
 
@@ -328,12 +355,13 @@ class StableDiffusionInstructPix2PixPipeline(DiffusionPipeline, TextualInversion
 
         # 9. Denoising loop
         num_warmup_steps = len(timesteps) - num_inference_steps * self.scheduler.order
+        self._num_timesteps = len(timesteps)
         with self.progress_bar(total=num_inference_steps) as progress_bar:
             for i, t in enumerate(timesteps):
                 # Expand the latents if we are doing classifier free guidance.
                 # The latents are expanded 3 times because for pix2pix the guidance\
                 # is applied for both the text and the input image.
-                latent_model_input = torch.cat([latents] * 3) if do_classifier_free_guidance else latents
+                latent_model_input = torch.cat([latents] * 3) if self.do_classifier_free_guidance else latents
 
                 # concat latents, image_latents in the channel dimension
                 scaled_latent_model_input = self.scheduler.scale_model_input(latent_model_input, t)
@@ -354,12 +382,12 @@ class StableDiffusionInstructPix2PixPipeline(DiffusionPipeline, TextualInversion
                     noise_pred = latent_model_input - sigma * noise_pred
 
                 # perform guidance
-                if do_classifier_free_guidance:
+                if self.do_classifier_free_guidance:
                     noise_pred_text, noise_pred_image, noise_pred_uncond = noise_pred.chunk(3)
                     noise_pred = (
                         noise_pred_uncond
-                        + guidance_scale * (noise_pred_text - noise_pred_image)
-                        + image_guidance_scale * (noise_pred_image - noise_pred_uncond)
+                        + self.guidance_scale * (noise_pred_text - noise_pred_image)
+                        + self.image_guidance_scale * (noise_pred_image - noise_pred_uncond)
                     )
 
                 # Hack:
@@ -374,6 +402,17 @@ class StableDiffusionInstructPix2PixPipeline(DiffusionPipeline, TextualInversion
                 # compute the previous noisy sample x_t -> x_t-1
                 latents = self.scheduler.step(noise_pred, t, latents, **extra_step_kwargs, return_dict=False)[0]
 
+                if callback_on_step_end is not None:
+                    callback_kwargs = {}
+                    for k in callback_on_step_end_tensor_inputs:
+                        callback_kwargs[k] = locals()[k]
+                    callback_outputs = callback_on_step_end(self, i, t, callback_kwargs)
+
+                    latents = callback_outputs.pop("latents", latents)
+                    prompt_embeds = callback_outputs.pop("prompt_embeds", prompt_embeds)
+                    negative_prompt_embeds = callback_outputs.pop("negative_prompt_embeds", negative_prompt_embeds)
+                    image_latents = callback_outputs.pop("image_latents", image_latents)
+
                 # call the callback, if provided
                 if i == len(timesteps) - 1 or ((i + 1) > num_warmup_steps and (i + 1) % self.scheduler.order == 0):
                     progress_bar.update()
@@ -596,16 +635,27 @@ class StableDiffusionInstructPix2PixPipeline(DiffusionPipeline, TextualInversion
         return image
 
     def check_inputs(
-        self, prompt, callback_steps, negative_prompt=None, prompt_embeds=None, negative_prompt_embeds=None
-    ):
-        if (callback_steps is None) or (
-            callback_steps is not None and (not isinstance(callback_steps, int) or callback_steps <= 0)
+        self,
+        prompt,
+        callback_steps,
+        negative_prompt=None,
+        prompt_embeds=None,
+        negative_prompt_embeds=None,
+        callback_on_step_end_tensor_inputs=None,
     ):
+        if callback_steps is not None and (not isinstance(callback_steps, int) or callback_steps <= 0):
             raise ValueError(
                 f"`callback_steps` has to be a positive integer but is {callback_steps} of type"
                 f" {type(callback_steps)}."
             )
 
+        if callback_on_step_end_tensor_inputs is not None and not all(
+            k in self._callback_tensor_inputs for k in callback_on_step_end_tensor_inputs
+        ):
+            raise ValueError(
+                f"`callback_on_step_end_tensor_inputs` has to be in {self._callback_tensor_inputs}, but found {[k for k in callback_on_step_end_tensor_inputs if k not in self._callback_tensor_inputs]}"
+            )
+
         if prompt is not None and prompt_embeds is not None:
             raise ValueError(
                 f"Cannot forward both `prompt`: {prompt} and `prompt_embeds`: {prompt_embeds}. Please make sure to"
@@ -728,3 +778,22 @@ class StableDiffusionInstructPix2PixPipeline(DiffusionPipeline, TextualInversion
     def disable_freeu(self):
         """Disables the FreeU mechanism if enabled."""
         self.unet.disable_freeu()
+
+    @property
+    def guidance_scale(self):
+        return self._guidance_scale
+
+    @property
+    def image_guidance_scale(self):
+        return self._image_guidance_scale
+
+    @property
+    def num_timesteps(self):
+        return self._num_timesteps
+
+    # here `guidance_scale` is defined analog to the guidance weight `w` of equation (2)
+    # of the Imagen paper: https://arxiv.org/pdf/2205.11487.pdf . `guidance_scale = 1`
+    # corresponds to doing no classifier free guidance.
+    @property
+    def do_classifier_free_guidance(self):
+        return self.guidance_scale > 1.0 and self.image_guidance_scale >= 1.0

src/diffusers/pipelines/stable_diffusion/pipeline_stable_diffusion_k_diffusion.py

@@ -382,17 +382,22 @@ class StableDiffusionKDiffusionPipeline(DiffusionPipeline, TextualInversionLoade
         negative_prompt=None,
         prompt_embeds=None,
         negative_prompt_embeds=None,
+        callback_on_step_end_tensor_inputs=None,
     ):
         if height % 8 != 0 or width % 8 != 0:
             raise ValueError(f"`height` and `width` have to be divisible by 8 but are {height} and {width}.")
 
-        if (callback_steps is None) or (
-            callback_steps is not None and (not isinstance(callback_steps, int) or callback_steps <= 0)
-        ):
+        if callback_steps is not None and (not isinstance(callback_steps, int) or callback_steps <= 0):
             raise ValueError(
                 f"`callback_steps` has to be a positive integer but is {callback_steps} of type"
                 f" {type(callback_steps)}."
             )
+        if callback_on_step_end_tensor_inputs is not None and not all(
+            k in self._callback_tensor_inputs for k in callback_on_step_end_tensor_inputs
+        ):
+            raise ValueError(
+                f"`callback_on_step_end_tensor_inputs` has to be in {self._callback_tensor_inputs}, but found {[k for k in callback_on_step_end_tensor_inputs if k not in self._callback_tensor_inputs]}"
+            )
 
         if prompt is not None and prompt_embeds is not None:
             raise ValueError(

src/diffusers/pipelines/stable_diffusion/pipeline_stable_diffusion_ldm3d.py

@@ -452,17 +452,22 @@ class StableDiffusionLDM3DPipeline(
         negative_prompt=None,
         prompt_embeds=None,
         negative_prompt_embeds=None,
+        callback_on_step_end_tensor_inputs=None,
     ):
         if height % 8 != 0 or width % 8 != 0:
             raise ValueError(f"`height` and `width` have to be divisible by 8 but are {height} and {width}.")
 
-        if (callback_steps is None) or (
-            callback_steps is not None and (not isinstance(callback_steps, int) or callback_steps <= 0)
-        ):
+        if callback_steps is not None and (not isinstance(callback_steps, int) or callback_steps <= 0):
             raise ValueError(
                 f"`callback_steps` has to be a positive integer but is {callback_steps} of type"
                 f" {type(callback_steps)}."
             )
+        if callback_on_step_end_tensor_inputs is not None and not all(
+            k in self._callback_tensor_inputs for k in callback_on_step_end_tensor_inputs
+        ):
+            raise ValueError(
+                f"`callback_on_step_end_tensor_inputs` has to be in {self._callback_tensor_inputs}, but found {[k for k in callback_on_step_end_tensor_inputs if k not in self._callback_tensor_inputs]}"
+            )
 
         if prompt is not None and prompt_embeds is not None:
             raise ValueError(

src/diffusers/pipelines/stable_diffusion/pipeline_stable_diffusion_model_editing.py

@@ -433,17 +433,22 @@ class StableDiffusionModelEditingPipeline(DiffusionPipeline, TextualInversionLoa
         negative_prompt=None,
         prompt_embeds=None,
         negative_prompt_embeds=None,
+        callback_on_step_end_tensor_inputs=None,
     ):
         if height % 8 != 0 or width % 8 != 0:
             raise ValueError(f"`height` and `width` have to be divisible by 8 but are {height} and {width}.")
 
-        if (callback_steps is None) or (
-            callback_steps is not None and (not isinstance(callback_steps, int) or callback_steps <= 0)
-        ):
+        if callback_steps is not None and (not isinstance(callback_steps, int) or callback_steps <= 0):
             raise ValueError(
                 f"`callback_steps` has to be a positive integer but is {callback_steps} of type"
                 f" {type(callback_steps)}."
             )
+        if callback_on_step_end_tensor_inputs is not None and not all(
+            k in self._callback_tensor_inputs for k in callback_on_step_end_tensor_inputs
+        ):
+            raise ValueError(
+                f"`callback_on_step_end_tensor_inputs` has to be in {self._callback_tensor_inputs}, but found {[k for k in callback_on_step_end_tensor_inputs if k not in self._callback_tensor_inputs]}"
+            )
 
         if prompt is not None and prompt_embeds is not None:
             raise ValueError(

src/diffusers/pipelines/stable_diffusion/pipeline_stable_diffusion_panorama.py

@@ -430,17 +430,22 @@ class StableDiffusionPanoramaPipeline(DiffusionPipeline, TextualInversionLoaderM
         negative_prompt=None,
         prompt_embeds=None,
         negative_prompt_embeds=None,
+        callback_on_step_end_tensor_inputs=None,
     ):
         if height % 8 != 0 or width % 8 != 0:
             raise ValueError(f"`height` and `width` have to be divisible by 8 but are {height} and {width}.")
 
-        if (callback_steps is None) or (
-            callback_steps is not None and (not isinstance(callback_steps, int) or callback_steps <= 0)
-        ):
+        if callback_steps is not None and (not isinstance(callback_steps, int) or callback_steps <= 0):
             raise ValueError(
                 f"`callback_steps` has to be a positive integer but is {callback_steps} of type"
                 f" {type(callback_steps)}."
             )
+        if callback_on_step_end_tensor_inputs is not None and not all(
+            k in self._callback_tensor_inputs for k in callback_on_step_end_tensor_inputs
+        ):
+            raise ValueError(
+                f"`callback_on_step_end_tensor_inputs` has to be in {self._callback_tensor_inputs}, but found {[k for k in callback_on_step_end_tensor_inputs if k not in self._callback_tensor_inputs]}"
+            )
 
         if prompt is not None and prompt_embeds is not None:
             raise ValueError(

src/diffusers/pipelines/stable_diffusion/pipeline_stable_diffusion_paradigms.py

@@ -436,17 +436,22 @@ class StableDiffusionParadigmsPipeline(
         negative_prompt=None,
         prompt_embeds=None,
         negative_prompt_embeds=None,
+        callback_on_step_end_tensor_inputs=None,
     ):
         if height % 8 != 0 or width % 8 != 0:
             raise ValueError(f"`height` and `width` have to be divisible by 8 but are {height} and {width}.")
 
-        if (callback_steps is None) or (
-            callback_steps is not None and (not isinstance(callback_steps, int) or callback_steps <= 0)
-        ):
+        if callback_steps is not None and (not isinstance(callback_steps, int) or callback_steps <= 0):
             raise ValueError(
                 f"`callback_steps` has to be a positive integer but is {callback_steps} of type"
                 f" {type(callback_steps)}."
             )
+        if callback_on_step_end_tensor_inputs is not None and not all(
+            k in self._callback_tensor_inputs for k in callback_on_step_end_tensor_inputs
+        ):
+            raise ValueError(
+                f"`callback_on_step_end_tensor_inputs` has to be in {self._callback_tensor_inputs}, but found {[k for k in callback_on_step_end_tensor_inputs if k not in self._callback_tensor_inputs]}"
+            )
 
         if prompt is not None and prompt_embeds is not None:
             raise ValueError(

src/diffusers/pipelines/stable_diffusion/pipeline_stable_diffusion_sag.py

@@ -440,17 +440,22 @@ class StableDiffusionSAGPipeline(DiffusionPipeline, TextualInversionLoaderMixin)
         negative_prompt=None,
         prompt_embeds=None,
         negative_prompt_embeds=None,
+        callback_on_step_end_tensor_inputs=None,
     ):
         if height % 8 != 0 or width % 8 != 0:
             raise ValueError(f"`height` and `width` have to be divisible by 8 but are {height} and {width}.")
 
-        if (callback_steps is None) or (
-            callback_steps is not None and (not isinstance(callback_steps, int) or callback_steps <= 0)
-        ):
+        if callback_steps is not None and (not isinstance(callback_steps, int) or callback_steps <= 0):
             raise ValueError(
                 f"`callback_steps` has to be a positive integer but is {callback_steps} of type"
                 f" {type(callback_steps)}."
             )
+        if callback_on_step_end_tensor_inputs is not None and not all(
+            k in self._callback_tensor_inputs for k in callback_on_step_end_tensor_inputs
+        ):
+            raise ValueError(
+                f"`callback_on_step_end_tensor_inputs` has to be in {self._callback_tensor_inputs}, but found {[k for k in callback_on_step_end_tensor_inputs if k not in self._callback_tensor_inputs]}"
+            )
 
         if prompt is not None and prompt_embeds is not None:
             raise ValueError(

src/diffusers/pipelines/stable_diffusion_safe/pipeline_stable_diffusion_safe.py

@@ -364,17 +364,22 @@ class StableDiffusionPipelineSafe(DiffusionPipeline):
         negative_prompt=None,
         prompt_embeds=None,
         negative_prompt_embeds=None,
+        callback_on_step_end_tensor_inputs=None,
     ):
         if height % 8 != 0 or width % 8 != 0:
             raise ValueError(f"`height` and `width` have to be divisible by 8 but are {height} and {width}.")
 
-        if (callback_steps is None) or (
-            callback_steps is not None and (not isinstance(callback_steps, int) or callback_steps <= 0)
-        ):
+        if callback_steps is not None and (not isinstance(callback_steps, int) or callback_steps <= 0):
             raise ValueError(
                 f"`callback_steps` has to be a positive integer but is {callback_steps} of type"
                 f" {type(callback_steps)}."
             )
+        if callback_on_step_end_tensor_inputs is not None and not all(
+            k in self._callback_tensor_inputs for k in callback_on_step_end_tensor_inputs
+        ):
+            raise ValueError(
+                f"`callback_on_step_end_tensor_inputs` has to be in {self._callback_tensor_inputs}, but found {[k for k in callback_on_step_end_tensor_inputs if k not in self._callback_tensor_inputs]}"
+            )
 
         if prompt is not None and prompt_embeds is not None:
             raise ValueError(

src/diffusers/pipelines/stable_diffusion_xl/pipeline_stable_diffusion_xl.py

@@ -35,6 +35,7 @@ from ...models.lora import adjust_lora_scale_text_encoder
 from ...schedulers import KarrasDiffusionSchedulers
 from ...utils import (
     USE_PEFT_BACKEND,
+    deprecate,
     is_invisible_watermark_available,
     is_torch_xla_available,
     logging,
@@ -141,6 +142,15 @@ class StableDiffusionXLPipeline(
     """
     model_cpu_offload_seq = "text_encoder->text_encoder_2->unet->vae"
     _optional_components = ["tokenizer", "tokenizer_2", "text_encoder", "text_encoder_2"]
+    _callback_tensor_inputs = [
+        "latents",
+        "prompt_embeds",
+        "negative_prompt_embeds",
+        "add_text_embeds",
+        "add_time_ids",
+        "negative_pooled_prompt_embeds",
+        "negative_add_time_ids",
+    ]
 
     def __init__(
         self,
@@ -476,18 +486,24 @@ class StableDiffusionXLPipeline(
         negative_prompt_embeds=None,
         pooled_prompt_embeds=None,
         negative_pooled_prompt_embeds=None,
+        callback_on_step_end_tensor_inputs=None,
     ):
         if height % 8 != 0 or width % 8 != 0:
             raise ValueError(f"`height` and `width` have to be divisible by 8 but are {height} and {width}.")
 
-        if (callback_steps is None) or (
-            callback_steps is not None and (not isinstance(callback_steps, int) or callback_steps <= 0)
-        ):
+        if callback_steps is not None and (not isinstance(callback_steps, int) or callback_steps <= 0):
             raise ValueError(
                 f"`callback_steps` has to be a positive integer but is {callback_steps} of type"
                 f" {type(callback_steps)}."
             )
 
+        if callback_on_step_end_tensor_inputs is not None and not all(
+            k in self._callback_tensor_inputs for k in callback_on_step_end_tensor_inputs
+        ):
+            raise ValueError(
+                f"`callback_on_step_end_tensor_inputs` has to be in {self._callback_tensor_inputs}, but found {[k for k in callback_on_step_end_tensor_inputs if k not in self._callback_tensor_inputs]}"
+            )
+
         if prompt is not None and prompt_embeds is not None:
             raise ValueError(
                 f"Cannot forward both `prompt`: {prompt} and `prompt_embeds`: {prompt_embeds}. Please make sure to"
@@ -620,6 +636,37 @@ class StableDiffusionXLPipeline(
         """Disables the FreeU mechanism if enabled."""
         self.unet.disable_freeu()
 
+    @property
+    def guidance_scale(self):
+        return self._guidance_scale
+
+    @property
+    def guidance_rescale(self):
+        return self._guidance_rescale
+
+    @property
+    def clip_skip(self):
+        return self._clip_skip
+
+    # here `guidance_scale` is defined analog to the guidance weight `w` of equation (2)
+    # of the Imagen paper: https://arxiv.org/pdf/2205.11487.pdf . `guidance_scale = 1`
+    # corresponds to doing no classifier free guidance.
+    @property
+    def do_classifier_free_guidance(self):
+        return self._guidance_scale > 1
+
+    @property
+    def cross_attention_kwargs(self):
+        return self._cross_attention_kwargs
+
+    @property
+    def denoising_end(self):
+        return self._denoising_end
+
+    @property
+    def num_timesteps(self):
+        return self._num_timesteps
+
     @torch.no_grad()
     @replace_example_docstring(EXAMPLE_DOC_STRING)
     def __call__(
@@ -643,8 +690,6 @@ class StableDiffusionXLPipeline(
         negative_pooled_prompt_embeds: Optional[torch.FloatTensor] = None,
         output_type: Optional[str] = "pil",
         return_dict: bool = True,
-        callback: Optional[Callable[[int, int, torch.FloatTensor], None]] = None,
-        callback_steps: int = 1,
         cross_attention_kwargs: Optional[Dict[str, Any]] = None,
         guidance_rescale: float = 0.0,
         original_size: Optional[Tuple[int, int]] = None,
@@ -654,6 +699,9 @@ class StableDiffusionXLPipeline(
         negative_crops_coords_top_left: Tuple[int, int] = (0, 0),
         negative_target_size: Optional[Tuple[int, int]] = None,
         clip_skip: Optional[int] = None,
+        callback_on_step_end: Optional[Callable[[int, int, Dict], None]] = None,
+        callback_on_step_end_tensor_inputs: List[str] = ["latents"],
+        **kwargs,
     ):
         r"""
         Function invoked when calling the pipeline for generation.
@@ -730,12 +778,6 @@ class StableDiffusionXLPipeline(
             return_dict (`bool`, *optional*, defaults to `True`):
                 Whether or not to return a [`~pipelines.stable_diffusion_xl.StableDiffusionXLPipelineOutput`] instead
                 of a plain tuple.
-            callback (`Callable`, *optional*):
-                A function that will be called every `callback_steps` steps during inference. The function will be
-                called with the following arguments: `callback(step: int, timestep: int, latents: torch.FloatTensor)`.
-            callback_steps (`int`, *optional*, defaults to 1):
-                The frequency at which the `callback` function will be called. If not specified, the callback will be
-                called at every step.
             cross_attention_kwargs (`dict`, *optional*):
                 A kwargs dictionary that if specified is passed along to the `AttentionProcessor` as defined under
                 `self.processor` in
@@ -774,6 +816,15 @@ class StableDiffusionXLPipeline(
                 as the `target_size` for most cases. Part of SDXL's micro-conditioning as explained in section 2.2 of
                 [https://huggingface.co/papers/2307.01952](https://huggingface.co/papers/2307.01952). For more
                 information, refer to this issue thread: https://github.com/huggingface/diffusers/issues/4208.
+            callback_on_step_end (`Callable`, *optional*):
+                A function that calls at the end of each denoising steps during the inference. The function is called
+                with the following arguments: `callback_on_step_end(self: DiffusionPipeline, step: int, timestep: int,
+                callback_kwargs: Dict)`. `callback_kwargs` will include a list of all tensors as specified by
+                `callback_on_step_end_tensor_inputs`.
+            callback_on_step_end_tensor_inputs (`List`, *optional*):
+                The list of tensor inputs for the `callback_on_step_end` function. The tensors specified in the list
+                will be passed as `callback_kwargs` argument. You will only be able to include variables listed in the
+                `._callback_tensor_inputs` attribute of your pipeine class.
 
         Examples:
 
@@ -782,6 +833,23 @@ class StableDiffusionXLPipeline(
             [`~pipelines.stable_diffusion_xl.StableDiffusionXLPipelineOutput`] if `return_dict` is True, otherwise a
             `tuple`. When returning a tuple, the first element is a list with the generated images.
         """
+
+        callback = kwargs.pop("callback", None)
+        callback_steps = kwargs.pop("callback_steps", None)
+
+        if callback is not None:
+            deprecate(
+                "callback",
+                "1.0.0",
+                "Passing `callback` as an input argument to `__call__` is deprecated, consider use `callback_on_step_end`",
+            )
+        if callback_steps is not None:
+            deprecate(
+                "callback_steps",
+                "1.0.0",
+                "Passing `callback_steps` as an input argument to `__call__` is deprecated, consider use `callback_on_step_end`",
+            )
+
         # 0. Default height and width to unet
         height = height or self.default_sample_size * self.vae_scale_factor
         width = width or self.default_sample_size * self.vae_scale_factor
@@ -802,8 +870,15 @@ class StableDiffusionXLPipeline(
             negative_prompt_embeds,
             pooled_prompt_embeds,
             negative_pooled_prompt_embeds,
+            callback_on_step_end_tensor_inputs,
         )
 
+        self._guidance_scale = guidance_scale
+        self._guidance_rescale = guidance_rescale
+        self._clip_skip = clip_skip
+        self._cross_attention_kwargs = cross_attention_kwargs
+        self._denoising_end = denoising_end
+
         # 2. Define call parameters
         if prompt is not None and isinstance(prompt, str):
             batch_size = 1
@@ -814,13 +889,10 @@ class StableDiffusionXLPipeline(
 
         device = self._execution_device
 
-        # here `guidance_scale` is defined analog to the guidance weight `w` of equation (2)
-        # of the Imagen paper: https://arxiv.org/pdf/2205.11487.pdf . `guidance_scale = 1`
-        # corresponds to doing no classifier free guidance.
-        do_classifier_free_guidance = guidance_scale > 1.0
-
         # 3. Encode input prompt
-        lora_scale = cross_attention_kwargs.get("scale", None) if cross_attention_kwargs is not None else None
+        lora_scale = (
+            self.cross_attention_kwargs.get("scale", None) if self.cross_attention_kwargs is not None else None
+        )
 
         (
             prompt_embeds,
@@ -832,7 +904,7 @@ class StableDiffusionXLPipeline(
             prompt_2=prompt_2,
             device=device,
             num_images_per_prompt=num_images_per_prompt,
-            do_classifier_free_guidance=do_classifier_free_guidance,
+            do_classifier_free_guidance=self.do_classifier_free_guidance,
             negative_prompt=negative_prompt,
             negative_prompt_2=negative_prompt_2,
             prompt_embeds=prompt_embeds,
@@ -840,7 +912,7 @@ class StableDiffusionXLPipeline(
             pooled_prompt_embeds=pooled_prompt_embeds,
             negative_pooled_prompt_embeds=negative_pooled_prompt_embeds,
             lora_scale=lora_scale,
-            clip_skip=clip_skip,
+            clip_skip=self.clip_skip,
         )
 
         # 4. Prepare timesteps
@@ -889,7 +961,7 @@ class StableDiffusionXLPipeline(
         else:
             negative_add_time_ids = add_time_ids
 
-        if do_classifier_free_guidance:
+        if self.do_classifier_free_guidance:
             prompt_embeds = torch.cat([negative_prompt_embeds, prompt_embeds], dim=0)
             add_text_embeds = torch.cat([negative_pooled_prompt_embeds, add_text_embeds], dim=0)
             add_time_ids = torch.cat([negative_add_time_ids, add_time_ids], dim=0)
@@ -902,20 +974,26 @@ class StableDiffusionXLPipeline(
         num_warmup_steps = max(len(timesteps) - num_inference_steps * self.scheduler.order, 0)
 
         # 8.1 Apply denoising_end
-        if denoising_end is not None and isinstance(denoising_end, float) and denoising_end > 0 and denoising_end < 1:
+        if (
+            self.denoising_end is not None
+            and isinstance(self.denoising_end, float)
+            and self.denoising_end > 0
+            and self.denoising_end < 1
+        ):
             discrete_timestep_cutoff = int(
                 round(
                     self.scheduler.config.num_train_timesteps
-                    - (denoising_end * self.scheduler.config.num_train_timesteps)
+                    - (self.denoising_end * self.scheduler.config.num_train_timesteps)
                 )
             )
             num_inference_steps = len(list(filter(lambda ts: ts >= discrete_timestep_cutoff, timesteps)))
             timesteps = timesteps[:num_inference_steps]
 
+        self._num_timesteps = len(timesteps)
         with self.progress_bar(total=num_inference_steps) as progress_bar:
             for i, t in enumerate(timesteps):
                 # expand the latents if we are doing classifier free guidance
-                latent_model_input = torch.cat([latents] * 2) if do_classifier_free_guidance else latents
+                latent_model_input = torch.cat([latents] * 2) if self.do_classifier_free_guidance else latents
 
                 latent_model_input = self.scheduler.scale_model_input(latent_model_input, t)
 
@@ -925,23 +1003,39 @@ class StableDiffusionXLPipeline(
                     latent_model_input,
                     t,
                     encoder_hidden_states=prompt_embeds,
-                    cross_attention_kwargs=cross_attention_kwargs,
+                    cross_attention_kwargs=self.cross_attention_kwargs,
                     added_cond_kwargs=added_cond_kwargs,
                     return_dict=False,
                 )[0]
 
                 # perform guidance
-                if do_classifier_free_guidance:
+                if self.do_classifier_free_guidance:
                     noise_pred_uncond, noise_pred_text = noise_pred.chunk(2)
-                    noise_pred = noise_pred_uncond + guidance_scale * (noise_pred_text - noise_pred_uncond)
+                    noise_pred = noise_pred_uncond + self.guidance_scale * (noise_pred_text - noise_pred_uncond)
 
-                if do_classifier_free_guidance and guidance_rescale > 0.0:
+                if self.do_classifier_free_guidance and self.guidance_rescale > 0.0:
                     # Based on 3.4. in https://arxiv.org/pdf/2305.08891.pdf
-                    noise_pred = rescale_noise_cfg(noise_pred, noise_pred_text, guidance_rescale=guidance_rescale)
+                    noise_pred = rescale_noise_cfg(noise_pred, noise_pred_text, guidance_rescale=self.guidance_rescale)
 
                 # compute the previous noisy sample x_t -> x_t-1
                 latents = self.scheduler.step(noise_pred, t, latents, **extra_step_kwargs, return_dict=False)[0]
 
+                if callback_on_step_end is not None:
+                    callback_kwargs = {}
+                    for k in callback_on_step_end_tensor_inputs:
+                        callback_kwargs[k] = locals()[k]
+                    callback_outputs = callback_on_step_end(self, i, t, callback_kwargs)
+
+                    latents = callback_outputs.pop("latents", latents)
+                    prompt_embeds = callback_outputs.pop("prompt_embeds", prompt_embeds)
+                    negative_prompt_embeds = callback_outputs.pop("negative_prompt_embeds", negative_prompt_embeds)
+                    add_text_embeds = callback_outputs.pop("add_text_embeds", add_text_embeds)
+                    negative_pooled_prompt_embeds = callback_outputs.pop(
+                        "negative_pooled_prompt_embeds", negative_pooled_prompt_embeds
+                    )
+                    add_time_ids = callback_outputs.pop("add_time_ids", add_time_ids)
+                    negative_add_time_ids = callback_outputs.pop("negative_add_time_ids", negative_add_time_ids)
+
                 # call the callback, if provided
                 if i == len(timesteps) - 1 or ((i + 1) > num_warmup_steps and (i + 1) % self.scheduler.order == 0):
                     progress_bar.update()

src/diffusers/pipelines/stable_diffusion_xl/pipeline_stable_diffusion_xl_img2img.py

@@ -32,6 +32,7 @@ from ...models.lora import adjust_lora_scale_text_encoder
 from ...schedulers import KarrasDiffusionSchedulers
 from ...utils import (
     USE_PEFT_BACKEND,
+    deprecate,
     is_invisible_watermark_available,
     is_torch_xla_available,
     logging,
@@ -154,6 +155,15 @@ class StableDiffusionXLImg2ImgPipeline(
     """
     model_cpu_offload_seq = "text_encoder->text_encoder_2->unet->vae"
     _optional_components = ["tokenizer", "tokenizer_2", "text_encoder", "text_encoder_2"]
+    _callback_tensor_inputs = [
+        "latents",
+        "prompt_embeds",
+        "negative_prompt_embeds",
+        "add_text_embeds",
+        "add_time_ids",
+        "negative_pooled_prompt_embeds",
+        "add_neg_time_ids",
+    ]
 
     def __init__(
         self,
@@ -488,6 +498,7 @@ class StableDiffusionXLImg2ImgPipeline(
         negative_prompt_2=None,
         prompt_embeds=None,
         negative_prompt_embeds=None,
+        callback_on_step_end_tensor_inputs=None,
     ):
         if strength < 0 or strength > 1:
             raise ValueError(f"The value of strength should in [0.0, 1.0] but is {strength}")
@@ -498,14 +509,19 @@ class StableDiffusionXLImg2ImgPipeline(
                 f"`num_inference_steps` has to be a positive integer but is {num_inference_steps} of type"
                 f" {type(num_inference_steps)}."
             )
-        if (callback_steps is None) or (
-            callback_steps is not None and (not isinstance(callback_steps, int) or callback_steps <= 0)
-        ):
+        if callback_steps is not None and (not isinstance(callback_steps, int) or callback_steps <= 0):
             raise ValueError(
                 f"`callback_steps` has to be a positive integer but is {callback_steps} of type"
                 f" {type(callback_steps)}."
             )
 
+        if callback_on_step_end_tensor_inputs is not None and not all(
+            k in self._callback_tensor_inputs for k in callback_on_step_end_tensor_inputs
+        ):
+            raise ValueError(
+                f"`callback_on_step_end_tensor_inputs` has to be in {self._callback_tensor_inputs}, but found {[k for k in callback_on_step_end_tensor_inputs if k not in self._callback_tensor_inputs]}"
+            )
+
         if prompt is not None and prompt_embeds is not None:
             raise ValueError(
                 f"Cannot forward both `prompt`: {prompt} and `prompt_embeds`: {prompt_embeds}. Please make sure to"
@@ -747,6 +763,41 @@ class StableDiffusionXLImg2ImgPipeline(
         """Disables the FreeU mechanism if enabled."""
         self.unet.disable_freeu()
 
+    @property
+    def guidance_scale(self):
+        return self._guidance_scale
+
+    @property
+    def guidance_rescale(self):
+        return self._guidance_rescale
+
+    @property
+    def clip_skip(self):
+        return self._clip_skip
+
+    # here `guidance_scale` is defined analog to the guidance weight `w` of equation (2)
+    # of the Imagen paper: https://arxiv.org/pdf/2205.11487.pdf . `guidance_scale = 1`
+    # corresponds to doing no classifier free guidance.
+    @property
+    def do_classifier_free_guidance(self):
+        return self._guidance_scale > 1
+
+    @property
+    def cross_attention_kwargs(self):
+        return self._cross_attention_kwargs
+
+    @property
+    def denoising_end(self):
+        return self._denoising_end
+
+    @property
+    def denoising_start(self):
+        return self._denoising_start
+
+    @property
+    def num_timesteps(self):
+        return self._num_timesteps
+
     @torch.no_grad()
     @replace_example_docstring(EXAMPLE_DOC_STRING)
     def __call__(
@@ -771,8 +822,6 @@ class StableDiffusionXLImg2ImgPipeline(
         negative_pooled_prompt_embeds: Optional[torch.FloatTensor] = None,
         output_type: Optional[str] = "pil",
         return_dict: bool = True,
-        callback: Optional[Callable[[int, int, torch.FloatTensor], None]] = None,
-        callback_steps: int = 1,
         cross_attention_kwargs: Optional[Dict[str, Any]] = None,
         guidance_rescale: float = 0.0,
         original_size: Tuple[int, int] = None,
@@ -784,6 +833,9 @@ class StableDiffusionXLImg2ImgPipeline(
         aesthetic_score: float = 6.0,
         negative_aesthetic_score: float = 2.5,
         clip_skip: Optional[int] = None,
+        callback_on_step_end: Optional[Callable[[int, int, Dict], None]] = None,
+        callback_on_step_end_tensor_inputs: List[str] = ["latents"],
+        **kwargs,
     ):
         r"""
         Function invoked when calling the pipeline for generation.
@@ -867,12 +919,6 @@ class StableDiffusionXLImg2ImgPipeline(
             return_dict (`bool`, *optional*, defaults to `True`):
                 Whether or not to return a [`~pipelines.stable_diffusion.StableDiffusionXLPipelineOutput`] instead of a
                 plain tuple.
-            callback (`Callable`, *optional*):
-                A function that will be called every `callback_steps` steps during inference. The function will be
-                called with the following arguments: `callback(step: int, timestep: int, latents: torch.FloatTensor)`.
-            callback_steps (`int`, *optional*, defaults to 1):
-                The frequency at which the `callback` function will be called. If not specified, the callback will be
-                called at every step.
             cross_attention_kwargs (`dict`, *optional*):
                 A kwargs dictionary that if specified is passed along to the `AttentionProcessor` as defined under
                 `self.processor` in
@@ -922,6 +968,15 @@ class StableDiffusionXLImg2ImgPipeline(
             clip_skip (`int`, *optional*):
                 Number of layers to be skipped from CLIP while computing the prompt embeddings. A value of 1 means that
                 the output of the pre-final layer will be used for computing the prompt embeddings.
+            callback_on_step_end (`Callable`, *optional*):
+                A function that calls at the end of each denoising steps during the inference. The function is called
+                with the following arguments: `callback_on_step_end(self: DiffusionPipeline, step: int, timestep: int,
+                callback_kwargs: Dict)`. `callback_kwargs` will include a list of all tensors as specified by
+                `callback_on_step_end_tensor_inputs`.
+            callback_on_step_end_tensor_inputs (`List`, *optional*):
+                The list of tensor inputs for the `callback_on_step_end` function. The tensors specified in the list
+                will be passed as `callback_kwargs` argument. You will only be able to include variables listed in the
+                `._callback_tensor_inputs` attribute of your pipeine class.
 
         Examples:
 
@@ -930,6 +985,23 @@ class StableDiffusionXLImg2ImgPipeline(
             [`~pipelines.stable_diffusion.StableDiffusionXLPipelineOutput`] if `return_dict` is True, otherwise a
             `tuple. When returning a tuple, the first element is a list with the generated images.
         """
+
+        callback = kwargs.pop("callback", None)
+        callback_steps = kwargs.pop("callback_steps", None)
+
+        if callback is not None:
+            deprecate(
+                "callback",
+                "1.0.0",
+                "Passing `callback` as an input argument to `__call__` is deprecated, consider use `callback_on_step_end`",
+            )
+        if callback_steps is not None:
+            deprecate(
+                "callback_steps",
+                "1.0.0",
+                "Passing `callback_steps` as an input argument to `__call__` is deprecated, consider use `callback_on_step_end`",
+            )
+
         # 1. Check inputs. Raise error if not correct
         self.check_inputs(
             prompt,
@@ -941,8 +1013,16 @@ class StableDiffusionXLImg2ImgPipeline(
             negative_prompt_2,
             prompt_embeds,
             negative_prompt_embeds,
+            callback_on_step_end_tensor_inputs,
         )
 
+        self._guidance_scale = guidance_scale
+        self._guidance_rescale = guidance_rescale
+        self._clip_skip = clip_skip
+        self._cross_attention_kwargs = cross_attention_kwargs
+        self._denoising_end = denoising_end
+        self._denoising_start = denoising_start
+
         # 2. Define call parameters
         if prompt is not None and isinstance(prompt, str):
             batch_size = 1
@@ -953,14 +1033,9 @@ class StableDiffusionXLImg2ImgPipeline(
 
         device = self._execution_device
 
-        # here `guidance_scale` is defined analog to the guidance weight `w` of equation (2)
-        # of the Imagen paper: https://arxiv.org/pdf/2205.11487.pdf . `guidance_scale = 1`
-        # corresponds to doing no classifier free guidance.
-        do_classifier_free_guidance = guidance_scale > 1.0
-
         # 3. Encode input prompt
         text_encoder_lora_scale = (
-            cross_attention_kwargs.get("scale", None) if cross_attention_kwargs is not None else None
+            self.cross_attention_kwargs.get("scale", None) if self.cross_attention_kwargs is not None else None
         )
         (
             prompt_embeds,
@@ -972,7 +1047,7 @@ class StableDiffusionXLImg2ImgPipeline(
             prompt_2=prompt_2,
             device=device,
             num_images_per_prompt=num_images_per_prompt,
-            do_classifier_free_guidance=do_classifier_free_guidance,
+            do_classifier_free_guidance=self.do_classifier_free_guidance,
             negative_prompt=negative_prompt,
             negative_prompt_2=negative_prompt_2,
             prompt_embeds=prompt_embeds,
@@ -980,7 +1055,7 @@ class StableDiffusionXLImg2ImgPipeline(
             pooled_prompt_embeds=pooled_prompt_embeds,
             negative_pooled_prompt_embeds=negative_pooled_prompt_embeds,
             lora_scale=text_encoder_lora_scale,
-            clip_skip=clip_skip,
+            clip_skip=self.clip_skip,
         )
 
         # 4. Preprocess image
@@ -988,15 +1063,18 @@ class StableDiffusionXLImg2ImgPipeline(
 
         # 5. Prepare timesteps
         def denoising_value_valid(dnv):
-            return isinstance(denoising_end, float) and 0 < dnv < 1
+            return isinstance(self.denoising_end, float) and 0 < dnv < 1
 
         self.scheduler.set_timesteps(num_inference_steps, device=device)
         timesteps, num_inference_steps = self.get_timesteps(
-            num_inference_steps, strength, device, denoising_start=denoising_start if denoising_value_valid else None
+            num_inference_steps,
+            strength,
+            device,
+            denoising_start=self.denoising_start if denoising_value_valid else None,
         )
         latent_timestep = timesteps[:1].repeat(batch_size * num_images_per_prompt)
 
-        add_noise = True if denoising_start is None else False
+        add_noise = True if self.denoising_start is None else False
         # 6. Prepare latent variables
         latents = self.prepare_latents(
             image,
@@ -1044,7 +1122,7 @@ class StableDiffusionXLImg2ImgPipeline(
         )
         add_time_ids = add_time_ids.repeat(batch_size * num_images_per_prompt, 1)
 
-        if do_classifier_free_guidance:
+        if self.do_classifier_free_guidance:
             prompt_embeds = torch.cat([negative_prompt_embeds, prompt_embeds], dim=0)
             add_text_embeds = torch.cat([negative_pooled_prompt_embeds, add_text_embeds], dim=0)
             add_neg_time_ids = add_neg_time_ids.repeat(batch_size * num_images_per_prompt, 1)
@@ -1059,30 +1137,30 @@ class StableDiffusionXLImg2ImgPipeline(
 
         # 9.1 Apply denoising_end
         if (
-            denoising_end is not None
-            and denoising_start is not None
-            and denoising_value_valid(denoising_end)
-            and denoising_value_valid(denoising_start)
-            and denoising_start >= denoising_end
+            self.denoising_end is not None
+            and self.denoising_start is not None
+            and denoising_value_valid(self.denoising_end)
+            and denoising_value_valid(self.denoising_start)
+            and self.denoising_start >= self.denoising_end
         ):
             raise ValueError(
-                f"`denoising_start`: {denoising_start} cannot be larger than or equal to `denoising_end`: "
-                + f" {denoising_end} when using type float."
+                f"`denoising_start`: {self.denoising_start} cannot be larger than or equal to `denoising_end`: "
+                + f" {self.denoising_end} when using type float."
             )
-        elif denoising_end is not None and denoising_value_valid(denoising_end):
+        elif self.denoising_end is not None and denoising_value_valid(self.denoising_end):
             discrete_timestep_cutoff = int(
                 round(
                     self.scheduler.config.num_train_timesteps
-                    - (denoising_end * self.scheduler.config.num_train_timesteps)
+                    - (self.denoising_end * self.scheduler.config.num_train_timesteps)
                 )
             )
             num_inference_steps = len(list(filter(lambda ts: ts >= discrete_timestep_cutoff, timesteps)))
             timesteps = timesteps[:num_inference_steps]
-
+        self._num_timesteps = len(timesteps)
         with self.progress_bar(total=num_inference_steps) as progress_bar:
             for i, t in enumerate(timesteps):
                 # expand the latents if we are doing classifier free guidance
-                latent_model_input = torch.cat([latents] * 2) if do_classifier_free_guidance else latents
+                latent_model_input = torch.cat([latents] * 2) if self.do_classifier_free_guidance else latents
 
                 latent_model_input = self.scheduler.scale_model_input(latent_model_input, t)
 
@@ -1092,23 +1170,39 @@ class StableDiffusionXLImg2ImgPipeline(
                     latent_model_input,
                     t,
                     encoder_hidden_states=prompt_embeds,
-                    cross_attention_kwargs=cross_attention_kwargs,
+                    cross_attention_kwargs=self.cross_attention_kwargs,
                     added_cond_kwargs=added_cond_kwargs,
                     return_dict=False,
                 )[0]
 
                 # perform guidance
-                if do_classifier_free_guidance:
+                if self.do_classifier_free_guidance:
                     noise_pred_uncond, noise_pred_text = noise_pred.chunk(2)
-                    noise_pred = noise_pred_uncond + guidance_scale * (noise_pred_text - noise_pred_uncond)
+                    noise_pred = noise_pred_uncond + self.guidance_scale * (noise_pred_text - noise_pred_uncond)
 
-                if do_classifier_free_guidance and guidance_rescale > 0.0:
+                if self.do_classifier_free_guidance and self.guidance_rescale > 0.0:
                     # Based on 3.4. in https://arxiv.org/pdf/2305.08891.pdf
-                    noise_pred = rescale_noise_cfg(noise_pred, noise_pred_text, guidance_rescale=guidance_rescale)
+                    noise_pred = rescale_noise_cfg(noise_pred, noise_pred_text, guidance_rescale=self.guidance_rescale)
 
                 # compute the previous noisy sample x_t -> x_t-1
                 latents = self.scheduler.step(noise_pred, t, latents, **extra_step_kwargs, return_dict=False)[0]
 
+                if callback_on_step_end is not None:
+                    callback_kwargs = {}
+                    for k in callback_on_step_end_tensor_inputs:
+                        callback_kwargs[k] = locals()[k]
+                    callback_outputs = callback_on_step_end(self, i, t, callback_kwargs)
+
+                    latents = callback_outputs.pop("latents", latents)
+                    prompt_embeds = callback_outputs.pop("prompt_embeds", prompt_embeds)
+                    negative_prompt_embeds = callback_outputs.pop("negative_prompt_embeds", negative_prompt_embeds)
+                    add_text_embeds = callback_outputs.pop("add_text_embeds", add_text_embeds)
+                    negative_pooled_prompt_embeds = callback_outputs.pop(
+                        "negative_pooled_prompt_embeds", negative_pooled_prompt_embeds
+                    )
+                    add_time_ids = callback_outputs.pop("add_time_ids", add_time_ids)
+                    add_neg_time_ids = callback_outputs.pop("add_neg_time_ids", add_neg_time_ids)
+
                 # call the callback, if provided
                 if i == len(timesteps) - 1 or ((i + 1) > num_warmup_steps and (i + 1) % self.scheduler.order == 0):
                     progress_bar.update()

src/diffusers/pipelines/stable_diffusion_xl/pipeline_stable_diffusion_xl_inpaint.py

@@ -301,6 +301,17 @@ class StableDiffusionXLInpaintPipeline(
     model_cpu_offload_seq = "text_encoder->text_encoder_2->unet->vae"
 
     _optional_components = ["tokenizer", "tokenizer_2", "text_encoder", "text_encoder_2"]
+    _callback_tensor_inputs = [
+        "latents",
+        "prompt_embeds",
+        "negative_prompt_embeds",
+        "add_text_embeds",
+        "add_time_ids",
+        "negative_pooled_prompt_embeds",
+        "add_neg_time_ids",
+        "mask",
+        "masked_image_latents",
+    ]
 
     def __init__(
         self,
@@ -639,6 +650,7 @@ class StableDiffusionXLInpaintPipeline(
         negative_prompt_2=None,
         prompt_embeds=None,
         negative_prompt_embeds=None,
+        callback_on_step_end_tensor_inputs=None,
     ):
         if strength < 0 or strength > 1:
             raise ValueError(f"The value of strength should in [0.0, 1.0] but is {strength}")
@@ -646,14 +658,19 @@ class StableDiffusionXLInpaintPipeline(
         if height % 8 != 0 or width % 8 != 0:
             raise ValueError(f"`height` and `width` have to be divisible by 8 but are {height} and {width}.")
 
-        if (callback_steps is None) or (
-            callback_steps is not None and (not isinstance(callback_steps, int) or callback_steps <= 0)
-        ):
+        if callback_steps is not None and (not isinstance(callback_steps, int) or callback_steps <= 0):
             raise ValueError(
                 f"`callback_steps` has to be a positive integer but is {callback_steps} of type"
                 f" {type(callback_steps)}."
             )
 
+        if callback_on_step_end_tensor_inputs is not None and not all(
+            k in self._callback_tensor_inputs for k in callback_on_step_end_tensor_inputs
+        ):
+            raise ValueError(
+                f"`callback_on_step_end_tensor_inputs` has to be in {self._callback_tensor_inputs}, but found {[k for k in callback_on_step_end_tensor_inputs if k not in self._callback_tensor_inputs]}"
+            )
+
         if prompt is not None and prompt_embeds is not None:
             raise ValueError(
                 f"Cannot forward both `prompt`: {prompt} and `prompt_embeds`: {prompt_embeds}. Please make sure to"
@@ -965,6 +982,41 @@ class StableDiffusionXLInpaintPipeline(
         """Disables the FreeU mechanism if enabled."""
         self.unet.disable_freeu()
 
+    @property
+    def guidance_scale(self):
+        return self._guidance_scale
+
+    @property
+    def guidance_rescale(self):
+        return self._guidance_rescale
+
+    @property
+    def clip_skip(self):
+        return self._clip_skip
+
+    # here `guidance_scale` is defined analog to the guidance weight `w` of equation (2)
+    # of the Imagen paper: https://arxiv.org/pdf/2205.11487.pdf . `guidance_scale = 1`
+    # corresponds to doing no classifier free guidance.
+    @property
+    def do_classifier_free_guidance(self):
+        return self._guidance_scale > 1
+
+    @property
+    def cross_attention_kwargs(self):
+        return self._cross_attention_kwargs
+
+    @property
+    def denoising_end(self):
+        return self._denoising_end
+
+    @property
+    def denoising_start(self):
+        return self._denoising_start
+
+    @property
+    def num_timesteps(self):
+        return self._num_timesteps
+
     @torch.no_grad()
     @replace_example_docstring(EXAMPLE_DOC_STRING)
     def __call__(
@@ -993,8 +1045,6 @@ class StableDiffusionXLInpaintPipeline(
         negative_pooled_prompt_embeds: Optional[torch.FloatTensor] = None,
         output_type: Optional[str] = "pil",
         return_dict: bool = True,
-        callback: Optional[Callable[[int, int, torch.FloatTensor], None]] = None,
-        callback_steps: int = 1,
         cross_attention_kwargs: Optional[Dict[str, Any]] = None,
         guidance_rescale: float = 0.0,
         original_size: Tuple[int, int] = None,
@@ -1006,6 +1056,9 @@ class StableDiffusionXLInpaintPipeline(
         aesthetic_score: float = 6.0,
         negative_aesthetic_score: float = 2.5,
         clip_skip: Optional[int] = None,
+        callback_on_step_end: Optional[Callable[[int, int, Dict], None]] = None,
+        callback_on_step_end_tensor_inputs: List[str] = ["latents"],
+        **kwargs,
     ):
         r"""
         Function invoked when calling the pipeline for generation.
@@ -1106,12 +1159,6 @@ class StableDiffusionXLInpaintPipeline(
             return_dict (`bool`, *optional*, defaults to `True`):
                 Whether or not to return a [`~pipelines.stable_diffusion.StableDiffusionPipelineOutput`] instead of a
                 plain tuple.
-            callback (`Callable`, *optional*):
-                A function that will be called every `callback_steps` steps during inference. The function will be
-                called with the following arguments: `callback(step: int, timestep: int, latents: torch.FloatTensor)`.
-            callback_steps (`int`, *optional*, defaults to 1):
-                The frequency at which the `callback` function will be called. If not specified, the callback will be
-                called at every step.
             cross_attention_kwargs (`dict`, *optional*):
                 A kwargs dictionary that if specified is passed along to the `AttentionProcessor` as defined under
                 `self.processor` in
@@ -1156,6 +1203,15 @@ class StableDiffusionXLInpaintPipeline(
             clip_skip (`int`, *optional*):
                 Number of layers to be skipped from CLIP while computing the prompt embeddings. A value of 1 means that
                 the output of the pre-final layer will be used for computing the prompt embeddings.
+            callback_on_step_end (`Callable`, *optional*):
+                A function that calls at the end of each denoising steps during the inference. The function is called
+                with the following arguments: `callback_on_step_end(self: DiffusionPipeline, step: int, timestep: int,
+                callback_kwargs: Dict)`. `callback_kwargs` will include a list of all tensors as specified by
+                `callback_on_step_end_tensor_inputs`.
+            callback_on_step_end_tensor_inputs (`List`, *optional*):
+                The list of tensor inputs for the `callback_on_step_end` function. The tensors specified in the list
+                will be passed as `callback_kwargs` argument. You will only be able to include variables listed in the
+                `._callback_tensor_inputs` attribute of your pipeine class.
 
         Examples:
 
@@ -1164,6 +1220,23 @@ class StableDiffusionXLInpaintPipeline(
             [`~pipelines.stable_diffusion.StableDiffusionXLPipelineOutput`] if `return_dict` is True, otherwise a
             `tuple. `tuple. When returning a tuple, the first element is a list with the generated images.
         """
+
+        callback = kwargs.pop("callback", None)
+        callback_steps = kwargs.pop("callback_steps", None)
+
+        if callback is not None:
+            deprecate(
+                "callback",
+                "1.0.0",
+                "Passing `callback` as an input argument to `__call__` is deprecated, consider use `callback_on_step_end`",
+            )
+        if callback_steps is not None:
+            deprecate(
+                "callback_steps",
+                "1.0.0",
+                "Passing `callback_steps` as an input argument to `__call__` is deprecated, consider use `callback_on_step_end`",
+            )
+
         # 0. Default height and width to unet
         height = height or self.unet.config.sample_size * self.vae_scale_factor
         width = width or self.unet.config.sample_size * self.vae_scale_factor
@@ -1180,8 +1253,16 @@ class StableDiffusionXLInpaintPipeline(
             negative_prompt_2,
             prompt_embeds,
             negative_prompt_embeds,
+            callback_on_step_end_tensor_inputs,
         )
 
+        self._guidance_scale = guidance_scale
+        self._guidance_rescale = guidance_rescale
+        self._clip_skip = clip_skip
+        self._cross_attention_kwargs = cross_attention_kwargs
+        self._denoising_end = denoising_end
+        self._denoising_start = denoising_start
+
         # 2. Define call parameters
         if prompt is not None and isinstance(prompt, str):
             batch_size = 1
@@ -1191,14 +1272,10 @@ class StableDiffusionXLInpaintPipeline(
             batch_size = prompt_embeds.shape[0]
 
         device = self._execution_device
-        # here `guidance_scale` is defined analog to the guidance weight `w` of equation (2)
-        # of the Imagen paper: https://arxiv.org/pdf/2205.11487.pdf . `guidance_scale = 1`
-        # corresponds to doing no classifier free guidance.
-        do_classifier_free_guidance = guidance_scale > 1.0
 
         # 3. Encode input prompt
         text_encoder_lora_scale = (
-            cross_attention_kwargs.get("scale", None) if cross_attention_kwargs is not None else None
+            self.cross_attention_kwargs.get("scale", None) if self.cross_attention_kwargs is not None else None
         )
 
         (
@@ -1211,7 +1288,7 @@ class StableDiffusionXLInpaintPipeline(
             prompt_2=prompt_2,
             device=device,
             num_images_per_prompt=num_images_per_prompt,
-            do_classifier_free_guidance=do_classifier_free_guidance,
+            do_classifier_free_guidance=self.do_classifier_free_guidance,
             negative_prompt=negative_prompt,
             negative_prompt_2=negative_prompt_2,
             prompt_embeds=prompt_embeds,
@@ -1219,16 +1296,19 @@ class StableDiffusionXLInpaintPipeline(
             pooled_prompt_embeds=pooled_prompt_embeds,
             negative_pooled_prompt_embeds=negative_pooled_prompt_embeds,
             lora_scale=text_encoder_lora_scale,
-            clip_skip=clip_skip,
+            clip_skip=self.clip_skip,
         )
 
         # 4. set timesteps
         def denoising_value_valid(dnv):
-            return isinstance(denoising_end, float) and 0 < dnv < 1
+            return isinstance(self.denoising_end, float) and 0 < dnv < 1
 
         self.scheduler.set_timesteps(num_inference_steps, device=device)
         timesteps, num_inference_steps = self.get_timesteps(
-            num_inference_steps, strength, device, denoising_start=denoising_start if denoising_value_valid else None
+            num_inference_steps,
+            strength,
+            device,
+            denoising_start=self.denoising_start if denoising_value_valid else None,
         )
         # check that number of inference steps is not < 1 - as this doesn't make sense
         if num_inference_steps < 1:
@@ -1260,7 +1340,7 @@ class StableDiffusionXLInpaintPipeline(
         num_channels_unet = self.unet.config.in_channels
         return_image_latents = num_channels_unet == 4
 
-        add_noise = True if denoising_start is None else False
+        add_noise = True if self.denoising_start is None else False
         latents_outputs = self.prepare_latents(
             batch_size * num_images_per_prompt,
             num_channels_latents,
@@ -1293,7 +1373,7 @@ class StableDiffusionXLInpaintPipeline(
             prompt_embeds.dtype,
             device,
             generator,
-            do_classifier_free_guidance,
+            self.do_classifier_free_guidance,
         )
 
         # 8. Check that sizes of mask, masked image and latents match
@@ -1350,7 +1430,7 @@ class StableDiffusionXLInpaintPipeline(
         )
         add_time_ids = add_time_ids.repeat(batch_size * num_images_per_prompt, 1)
 
-        if do_classifier_free_guidance:
+        if self.do_classifier_free_guidance:
             prompt_embeds = torch.cat([negative_prompt_embeds, prompt_embeds], dim=0)
             add_text_embeds = torch.cat([negative_pooled_prompt_embeds, add_text_embeds], dim=0)
             add_neg_time_ids = add_neg_time_ids.repeat(batch_size * num_images_per_prompt, 1)
@@ -1364,30 +1444,31 @@ class StableDiffusionXLInpaintPipeline(
         num_warmup_steps = max(len(timesteps) - num_inference_steps * self.scheduler.order, 0)
 
         if (
-            denoising_end is not None
-            and denoising_start is not None
-            and denoising_value_valid(denoising_end)
-            and denoising_value_valid(denoising_start)
-            and denoising_start >= denoising_end
+            self.denoising_end is not None
+            and self.denoising_start is not None
+            and denoising_value_valid(self.denoising_end)
+            and denoising_value_valid(self.denoising_start)
+            and self.denoising_start >= self.denoising_end
         ):
             raise ValueError(
-                f"`denoising_start`: {denoising_start} cannot be larger than or equal to `denoising_end`: "
-                + f" {denoising_end} when using type float."
+                f"`denoising_start`: {self.denoising_start} cannot be larger than or equal to `denoising_end`: "
+                + f" {self.denoising_end} when using type float."
             )
-        elif denoising_end is not None and denoising_value_valid(denoising_end):
+        elif self.denoising_end is not None and denoising_value_valid(self.denoising_end):
             discrete_timestep_cutoff = int(
                 round(
                     self.scheduler.config.num_train_timesteps
-                    - (denoising_end * self.scheduler.config.num_train_timesteps)
+                    - (self.denoising_end * self.scheduler.config.num_train_timesteps)
                 )
             )
             num_inference_steps = len(list(filter(lambda ts: ts >= discrete_timestep_cutoff, timesteps)))
             timesteps = timesteps[:num_inference_steps]
 
+        self._num_timesteps = len(timesteps)
         with self.progress_bar(total=num_inference_steps) as progress_bar:
             for i, t in enumerate(timesteps):
                 # expand the latents if we are doing classifier free guidance
-                latent_model_input = torch.cat([latents] * 2) if do_classifier_free_guidance else latents
+                latent_model_input = torch.cat([latents] * 2) if self.do_classifier_free_guidance else latents
 
                 # concat latents, mask, masked_image_latents in the channel dimension
                 latent_model_input = self.scheduler.scale_model_input(latent_model_input, t)
@@ -1401,26 +1482,26 @@ class StableDiffusionXLInpaintPipeline(
                     latent_model_input,
                     t,
                     encoder_hidden_states=prompt_embeds,
-                    cross_attention_kwargs=cross_attention_kwargs,
+                    cross_attention_kwargs=self.cross_attention_kwargs,
                     added_cond_kwargs=added_cond_kwargs,
                     return_dict=False,
                 )[0]
 
                 # perform guidance
-                if do_classifier_free_guidance:
+                if self.do_classifier_free_guidance:
                     noise_pred_uncond, noise_pred_text = noise_pred.chunk(2)
-                    noise_pred = noise_pred_uncond + guidance_scale * (noise_pred_text - noise_pred_uncond)
+                    noise_pred = noise_pred_uncond + self.guidance_scale * (noise_pred_text - noise_pred_uncond)
 
-                if do_classifier_free_guidance and guidance_rescale > 0.0:
+                if self.do_classifier_free_guidance and self.guidance_rescale > 0.0:
                     # Based on 3.4. in https://arxiv.org/pdf/2305.08891.pdf
-                    noise_pred = rescale_noise_cfg(noise_pred, noise_pred_text, guidance_rescale=guidance_rescale)
+                    noise_pred = rescale_noise_cfg(noise_pred, noise_pred_text, guidance_rescale=self.guidance_rescale)
 
                 # compute the previous noisy sample x_t -> x_t-1
                 latents = self.scheduler.step(noise_pred, t, latents, **extra_step_kwargs, return_dict=False)[0]
 
                 if num_channels_unet == 4:
                     init_latents_proper = image_latents
-                    if do_classifier_free_guidance:
+                    if self.do_classifier_free_guidance:
                         init_mask, _ = mask.chunk(2)
                     else:
                         init_mask = mask
@@ -1433,6 +1514,24 @@ class StableDiffusionXLInpaintPipeline(
 
                     latents = (1 - init_mask) * init_latents_proper + init_mask * latents
 
+                if callback_on_step_end is not None:
+                    callback_kwargs = {}
+                    for k in callback_on_step_end_tensor_inputs:
+                        callback_kwargs[k] = locals()[k]
+                    callback_outputs = callback_on_step_end(self, i, t, callback_kwargs)
+
+                    latents = callback_outputs.pop("latents", latents)
+                    prompt_embeds = callback_outputs.pop("prompt_embeds", prompt_embeds)
+                    negative_prompt_embeds = callback_outputs.pop("negative_prompt_embeds", negative_prompt_embeds)
+                    add_text_embeds = callback_outputs.pop("add_text_embeds", add_text_embeds)
+                    negative_pooled_prompt_embeds = callback_outputs.pop(
+                        "negative_pooled_prompt_embeds", negative_pooled_prompt_embeds
+                    )
+                    add_time_ids = callback_outputs.pop("add_time_ids", add_time_ids)
+                    add_neg_time_ids = callback_outputs.pop("add_neg_time_ids", add_neg_time_ids)
+                    mask = callback_outputs.pop("mask", mask)
+                    masked_image_latents = callback_outputs.pop("masked_image_latents", masked_image_latents)
+
                 # call the callback, if provided
                 if i == len(timesteps) - 1 or ((i + 1) > num_warmup_steps and (i + 1) % self.scheduler.order == 0):
                     progress_bar.update()

src/diffusers/pipelines/stable_diffusion_xl/pipeline_stable_diffusion_xl_instruct_pix2pix.py

@@ -446,16 +446,27 @@ class StableDiffusionXLInstructPix2PixPipeline(
 
     # Copied from diffusers.pipelines.stable_diffusion.pipeline_stable_diffusion_instruct_pix2pix.StableDiffusionInstructPix2PixPipeline.check_inputs
     def check_inputs(
-        self, prompt, callback_steps, negative_prompt=None, prompt_embeds=None, negative_prompt_embeds=None
-    ):
-        if (callback_steps is None) or (
-            callback_steps is not None and (not isinstance(callback_steps, int) or callback_steps <= 0)
+        self,
+        prompt,
+        callback_steps,
+        negative_prompt=None,
+        prompt_embeds=None,
+        negative_prompt_embeds=None,
+        callback_on_step_end_tensor_inputs=None,
     ):
+        if callback_steps is not None and (not isinstance(callback_steps, int) or callback_steps <= 0):
             raise ValueError(
                 f"`callback_steps` has to be a positive integer but is {callback_steps} of type"
                 f" {type(callback_steps)}."
             )
 
+        if callback_on_step_end_tensor_inputs is not None and not all(
+            k in self._callback_tensor_inputs for k in callback_on_step_end_tensor_inputs
+        ):
+            raise ValueError(
+                f"`callback_on_step_end_tensor_inputs` has to be in {self._callback_tensor_inputs}, but found {[k for k in callback_on_step_end_tensor_inputs if k not in self._callback_tensor_inputs]}"
+            )
+
         if prompt is not None and prompt_embeds is not None:
             raise ValueError(
                 f"Cannot forward both `prompt`: {prompt} and `prompt_embeds`: {prompt_embeds}. Please make sure to"

src/diffusers/pipelines/t2i_adapter/pipeline_stable_diffusion_xl_adapter.py

@@ -491,18 +491,24 @@ class StableDiffusionXLAdapterPipeline(
         negative_prompt_embeds=None,
         pooled_prompt_embeds=None,
         negative_pooled_prompt_embeds=None,
+        callback_on_step_end_tensor_inputs=None,
     ):
         if height % 8 != 0 or width % 8 != 0:
             raise ValueError(f"`height` and `width` have to be divisible by 8 but are {height} and {width}.")
 
-        if (callback_steps is None) or (
-            callback_steps is not None and (not isinstance(callback_steps, int) or callback_steps <= 0)
-        ):
+        if callback_steps is not None and (not isinstance(callback_steps, int) or callback_steps <= 0):
             raise ValueError(
                 f"`callback_steps` has to be a positive integer but is {callback_steps} of type"
                 f" {type(callback_steps)}."
             )
 
+        if callback_on_step_end_tensor_inputs is not None and not all(
+            k in self._callback_tensor_inputs for k in callback_on_step_end_tensor_inputs
+        ):
+            raise ValueError(
+                f"`callback_on_step_end_tensor_inputs` has to be in {self._callback_tensor_inputs}, but found {[k for k in callback_on_step_end_tensor_inputs if k not in self._callback_tensor_inputs]}"
+            )
+
         if prompt is not None and prompt_embeds is not None:
             raise ValueError(
                 f"Cannot forward both `prompt`: {prompt} and `prompt_embeds`: {prompt_embeds}. Please make sure to"

src/diffusers/pipelines/text_to_video_synthesis/pipeline_text_to_video_synth.py

@@ -416,17 +416,22 @@ class TextToVideoSDPipeline(DiffusionPipeline, TextualInversionLoaderMixin, Lora
         negative_prompt=None,
         prompt_embeds=None,
         negative_prompt_embeds=None,
+        callback_on_step_end_tensor_inputs=None,
     ):
         if height % 8 != 0 or width % 8 != 0:
             raise ValueError(f"`height` and `width` have to be divisible by 8 but are {height} and {width}.")
 
-        if (callback_steps is None) or (
-            callback_steps is not None and (not isinstance(callback_steps, int) or callback_steps <= 0)
-        ):
+        if callback_steps is not None and (not isinstance(callback_steps, int) or callback_steps <= 0):
             raise ValueError(
                 f"`callback_steps` has to be a positive integer but is {callback_steps} of type"
                 f" {type(callback_steps)}."
             )
+        if callback_on_step_end_tensor_inputs is not None and not all(
+            k in self._callback_tensor_inputs for k in callback_on_step_end_tensor_inputs
+        ):
+            raise ValueError(
+                f"`callback_on_step_end_tensor_inputs` has to be in {self._callback_tensor_inputs}, but found {[k for k in callback_on_step_end_tensor_inputs if k not in self._callback_tensor_inputs]}"
+            )
 
         if prompt is not None and prompt_embeds is not None:
             raise ValueError(

src/diffusers/pipelines/text_to_video_synthesis/pipeline_text_to_video_synth_img2img.py

@@ -471,19 +471,30 @@ class VideoToVideoSDPipeline(DiffusionPipeline, TextualInversionLoaderMixin, Lor
 
     # Copied from diffusers.pipelines.stable_diffusion.pipeline_stable_diffusion_img2img.StableDiffusionImg2ImgPipeline.check_inputs
     def check_inputs(
-        self, prompt, strength, callback_steps, negative_prompt=None, prompt_embeds=None, negative_prompt_embeds=None
+        self,
+        prompt,
+        strength,
+        callback_steps,
+        negative_prompt=None,
+        prompt_embeds=None,
+        negative_prompt_embeds=None,
+        callback_on_step_end_tensor_inputs=None,
     ):
         if strength < 0 or strength > 1:
             raise ValueError(f"The value of strength should in [0.0, 1.0] but is {strength}")
 
-        if (callback_steps is None) or (
-            callback_steps is not None and (not isinstance(callback_steps, int) or callback_steps <= 0)
-        ):
+        if callback_steps is not None and (not isinstance(callback_steps, int) or callback_steps <= 0):
             raise ValueError(
                 f"`callback_steps` has to be a positive integer but is {callback_steps} of type"
                 f" {type(callback_steps)}."
             )
 
+        if callback_on_step_end_tensor_inputs is not None and not all(
+            k in self._callback_tensor_inputs for k in callback_on_step_end_tensor_inputs
+        ):
+            raise ValueError(
+                f"`callback_on_step_end_tensor_inputs` has to be in {self._callback_tensor_inputs}, but found {[k for k in callback_on_step_end_tensor_inputs if k not in self._callback_tensor_inputs]}"
+            )
         if prompt is not None and prompt_embeds is not None:
             raise ValueError(
                 f"Cannot forward both `prompt`: {prompt} and `prompt_embeds`: {prompt_embeds}. Please make sure to"

src/diffusers/pipelines/versatile_diffusion/pipeline_versatile_diffusion_text_to_image.py

@@ -255,17 +255,22 @@ class VersatileDiffusionTextToImagePipeline(DiffusionPipeline):
         negative_prompt=None,
         prompt_embeds=None,
         negative_prompt_embeds=None,
+        callback_on_step_end_tensor_inputs=None,
     ):
         if height % 8 != 0 or width % 8 != 0:
             raise ValueError(f"`height` and `width` have to be divisible by 8 but are {height} and {width}.")
 
-        if (callback_steps is None) or (
-            callback_steps is not None and (not isinstance(callback_steps, int) or callback_steps <= 0)
-        ):
+        if callback_steps is not None and (not isinstance(callback_steps, int) or callback_steps <= 0):
             raise ValueError(
                 f"`callback_steps` has to be a positive integer but is {callback_steps} of type"
                 f" {type(callback_steps)}."
             )
+        if callback_on_step_end_tensor_inputs is not None and not all(
+            k in self._callback_tensor_inputs for k in callback_on_step_end_tensor_inputs
+        ):
+            raise ValueError(
+                f"`callback_on_step_end_tensor_inputs` has to be in {self._callback_tensor_inputs}, but found {[k for k in callback_on_step_end_tensor_inputs if k not in self._callback_tensor_inputs]}"
+            )
 
         if prompt is not None and prompt_embeds is not None:
             raise ValueError(

src/diffusers/pipelines/wuerstchen/pipeline_wuerstchen.py

@@ -12,14 +12,14 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from typing import Callable, List, Optional, Union
+from typing import Callable, Dict, List, Optional, Union
 
 import numpy as np
 import torch
 from transformers import CLIPTextModel, CLIPTokenizer
 
 from ...schedulers import DDPMWuerstchenScheduler
-from ...utils import logging, replace_example_docstring
+from ...utils import deprecate, logging, replace_example_docstring
 from ...utils.torch_utils import randn_tensor
 from ..pipeline_utils import DiffusionPipeline, ImagePipelineOutput
 from .modeling_paella_vq_model import PaellaVQModel
@@ -73,6 +73,12 @@ class WuerstchenDecoderPipeline(DiffusionPipeline):
     """
 
     model_cpu_offload_seq = "text_encoder->decoder->vqgan"
+    _callback_tensor_inputs = [
+        "latents",
+        "text_encoder_hidden_states",
+        "negative_prompt_embeds",
+        "image_embeddings",
+    ]
 
     def __init__(
         self,
@@ -187,6 +193,18 @@ class WuerstchenDecoderPipeline(DiffusionPipeline):
             # to avoid doing two forward passes
         return text_encoder_hidden_states, uncond_text_encoder_hidden_states
 
+    @property
+    def guidance_scale(self):
+        return self._guidance_scale
+
+    @property
+    def do_classifier_free_guidance(self):
+        return self._guidance_scale > 1
+
+    @property
+    def num_timesteps(self):
+        return self._num_timesteps
+
     @torch.no_grad()
     @replace_example_docstring(EXAMPLE_DOC_STRING)
     def __call__(
@@ -202,8 +220,9 @@ class WuerstchenDecoderPipeline(DiffusionPipeline):
         latents: Optional[torch.FloatTensor] = None,
         output_type: Optional[str] = "pil",
         return_dict: bool = True,
-        callback: Optional[Callable[[int, int, torch.FloatTensor], None]] = None,
-        callback_steps: int = 1,
+        callback_on_step_end: Optional[Callable[[int, int, Dict], None]] = None,
+        callback_on_step_end_tensor_inputs: List[str] = ["latents"],
+        **kwargs,
     ):
         """
         Function invoked when calling the pipeline for generation.
@@ -242,12 +261,15 @@ class WuerstchenDecoderPipeline(DiffusionPipeline):
                 (`np.array`) or `"pt"` (`torch.Tensor`).
             return_dict (`bool`, *optional*, defaults to `True`):
                 Whether or not to return a [`~pipelines.ImagePipelineOutput`] instead of a plain tuple.
-            callback (`Callable`, *optional*):
-                A function that will be called every `callback_steps` steps during inference. The function will be
-                called with the following arguments: `callback(step: int, timestep: int, latents: torch.FloatTensor)`.
-            callback_steps (`int`, *optional*, defaults to 1):
-                The frequency at which the `callback` function will be called. If not specified, the callback will be
-                called at every step.
+            callback_on_step_end (`Callable`, *optional*):
+                A function that calls at the end of each denoising steps during the inference. The function is called
+                with the following arguments: `callback_on_step_end(self: DiffusionPipeline, step: int, timestep: int,
+                callback_kwargs: Dict)`. `callback_kwargs` will include a list of all tensors as specified by
+                `callback_on_step_end_tensor_inputs`.
+            callback_on_step_end_tensor_inputs (`List`, *optional*):
+                The list of tensor inputs for the `callback_on_step_end` function. The tensors specified in the list
+                will be passed as `callback_kwargs` argument. You will only be able to include variables listed in the
+                `._callback_tensor_inputs` attribute of your pipeine class.
 
         Examples:
 
@@ -257,10 +279,33 @@ class WuerstchenDecoderPipeline(DiffusionPipeline):
             embeddings.
         """
 
+        callback = kwargs.pop("callback", None)
+        callback_steps = kwargs.pop("callback_steps", None)
+
+        if callback is not None:
+            deprecate(
+                "callback",
+                "1.0.0",
+                "Passing `callback` as an input argument to `__call__` is deprecated, consider use `callback_on_step_end`",
+            )
+        if callback_steps is not None:
+            deprecate(
+                "callback_steps",
+                "1.0.0",
+                "Passing `callback_steps` as an input argument to `__call__` is deprecated, consider use `callback_on_step_end`",
+            )
+
+        if callback_on_step_end_tensor_inputs is not None and not all(
+            k in self._callback_tensor_inputs for k in callback_on_step_end_tensor_inputs
+        ):
+            raise ValueError(
+                f"`callback_on_step_end_tensor_inputs` has to be in {self._callback_tensor_inputs}, but found {[k for k in callback_on_step_end_tensor_inputs if k not in self._callback_tensor_inputs]}"
+            )
+
         # 0. Define commonly used variables
         device = self._execution_device
         dtype = self.decoder.dtype
-        do_classifier_free_guidance = guidance_scale > 1.0
+        self._guidance_scale = guidance_scale
 
         # 1. Check inputs. Raise error if not correct
         if not isinstance(prompt, list):
@@ -269,7 +314,7 @@ class WuerstchenDecoderPipeline(DiffusionPipeline):
             else:
                 raise TypeError(f"'prompt' must be of type 'list' or 'str', but got {type(prompt)}.")
 
-        if do_classifier_free_guidance:
+        if self.do_classifier_free_guidance:
             if negative_prompt is not None and not isinstance(negative_prompt, list):
                 if isinstance(negative_prompt, str):
                     negative_prompt = [negative_prompt]
@@ -298,7 +343,7 @@ class WuerstchenDecoderPipeline(DiffusionPipeline):
             prompt,
             device,
             image_embeddings.size(0) * num_images_per_prompt,
-            do_classifier_free_guidance,
+            self.do_classifier_free_guidance,
             negative_prompt,
         )
         text_encoder_hidden_states = (
@@ -323,25 +368,26 @@ class WuerstchenDecoderPipeline(DiffusionPipeline):
         latents = self.prepare_latents(latent_features_shape, dtype, device, generator, latents, self.scheduler)
 
         # 6. Run denoising loop
+        self._num_timesteps = len(timesteps[:-1])
         for i, t in enumerate(self.progress_bar(timesteps[:-1])):
             ratio = t.expand(latents.size(0)).to(dtype)
             effnet = (
                 torch.cat([image_embeddings, torch.zeros_like(image_embeddings)])
-                if do_classifier_free_guidance
+                if self.do_classifier_free_guidance
                 else image_embeddings
             )
             # 7. Denoise latents
             predicted_latents = self.decoder(
-                torch.cat([latents] * 2) if do_classifier_free_guidance else latents,
-                r=torch.cat([ratio] * 2) if do_classifier_free_guidance else ratio,
+                torch.cat([latents] * 2) if self.do_classifier_free_guidance else latents,
+                r=torch.cat([ratio] * 2) if self.do_classifier_free_guidance else ratio,
                 effnet=effnet,
                 clip=text_encoder_hidden_states,
             )
 
             # 8. Check for classifier free guidance and apply it
-            if do_classifier_free_guidance:
+            if self.do_classifier_free_guidance:
                 predicted_latents_text, predicted_latents_uncond = predicted_latents.chunk(2)
-                predicted_latents = torch.lerp(predicted_latents_uncond, predicted_latents_text, guidance_scale)
+                predicted_latents = torch.lerp(predicted_latents_uncond, predicted_latents_text, self.guidance_scale)
 
             # 9. Renoise latents to next timestep
             latents = self.scheduler.step(
@@ -351,25 +397,41 @@ class WuerstchenDecoderPipeline(DiffusionPipeline):
                 generator=generator,
             ).prev_sample
 
+            if callback_on_step_end is not None:
+                callback_kwargs = {}
+                for k in callback_on_step_end_tensor_inputs:
+                    callback_kwargs[k] = locals()[k]
+                callback_outputs = callback_on_step_end(self, i, t, callback_kwargs)
+
+                latents = callback_outputs.pop("latents", latents)
+                image_embeddings = callback_outputs.pop("image_embeddings", image_embeddings)
+                text_encoder_hidden_states = callback_outputs.pop(
+                    "text_encoder_hidden_states", text_encoder_hidden_states
+                )
+
             if callback is not None and i % callback_steps == 0:
                 step_idx = i // getattr(self.scheduler, "order", 1)
                 callback(step_idx, t, latents)
 
+        if output_type not in ["pt", "np", "pil", "latent"]:
+            raise ValueError(
+                f"Only the output types `pt`, `np`, `pil` and `latent` are supported not output_type={output_type}"
+            )
+
+        if not output_type == "latent":
             # 10. Scale and decode the image latents with vq-vae
             latents = self.vqgan.config.scale_factor * latents
             images = self.vqgan.decode(latents).sample.clamp(0, 1)
-
-        # Offload all models
-        self.maybe_free_model_hooks()
-
-        if output_type not in ["pt", "np", "pil"]:
-            raise ValueError(f"Only the output types `pt`, `np` and `pil` are supported not output_type={output_type}")
-
             if output_type == "np":
                 images = images.permute(0, 2, 3, 1).cpu().numpy()
             elif output_type == "pil":
                 images = images.permute(0, 2, 3, 1).cpu().numpy()
                 images = self.numpy_to_pil(images)
+        else:
+            images = latents
+
+        # Offload all models
+        self.maybe_free_model_hooks()
 
         if not return_dict:
             return images

src/diffusers/pipelines/wuerstchen/pipeline_wuerstchen_combined.py

@@ -11,13 +11,13 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
-from typing import Callable, List, Optional, Union
+from typing import Callable, Dict, List, Optional, Union
 
 import torch
 from transformers import CLIPTextModel, CLIPTokenizer
 
 from ...schedulers import DDPMWuerstchenScheduler
-from ...utils import replace_example_docstring
+from ...utils import deprecate, replace_example_docstring
 from ..pipeline_utils import DiffusionPipeline
 from .modeling_paella_vq_model import PaellaVQModel
 from .modeling_wuerstchen_diffnext import WuerstchenDiffNeXt
@@ -161,10 +161,11 @@ class WuerstchenCombinedPipeline(DiffusionPipeline):
         latents: Optional[torch.FloatTensor] = None,
         output_type: Optional[str] = "pil",
         return_dict: bool = True,
-        prior_callback: Optional[Callable[[int, int, torch.FloatTensor], None]] = None,
-        prior_callback_steps: int = 1,
-        callback: Optional[Callable[[int, int, torch.FloatTensor], None]] = None,
-        callback_steps: int = 1,
+        prior_callback_on_step_end: Optional[Callable[[int, int, Dict], None]] = None,
+        prior_callback_on_step_end_tensor_inputs: List[str] = ["latents"],
+        callback_on_step_end: Optional[Callable[[int, int, Dict], None]] = None,
+        callback_on_step_end_tensor_inputs: List[str] = ["latents"],
+        **kwargs,
     ):
         """
         Function invoked when calling the pipeline for generation.
@@ -226,19 +227,23 @@ class WuerstchenCombinedPipeline(DiffusionPipeline):
                 (`np.array`) or `"pt"` (`torch.Tensor`).
             return_dict (`bool`, *optional*, defaults to `True`):
                 Whether or not to return a [`~pipelines.ImagePipelineOutput`] instead of a plain tuple.
-            prior_callback (`Callable`, *optional*):
-                A function that will be called every `prior_callback_steps` steps during inference. The function will
-                be called with the following arguments: `prior_callback(step: int, timestep: int, latents:
-                torch.FloatTensor)`.
-            prior_callback_steps (`int`, *optional*, defaults to 1):
-                The frequency at which the `callback` function will be called. If not specified, the callback will be
-                called at every step.
-            callback (`Callable`, *optional*):
-                A function that will be called every `callback_steps` steps during inference. The function will be
-                called with the following arguments: `callback(step: int, timestep: int, latents: torch.FloatTensor)`.
-            callback_steps (`int`, *optional*, defaults to 1):
-                The frequency at which the `callback` function will be called. If not specified, the callback will be
-                called at every step.
+            prior_callback_on_step_end (`Callable`, *optional*):
+                A function that calls at the end of each denoising steps during the inference. The function is called
+                with the following arguments: `prior_callback_on_step_end(self: DiffusionPipeline, step: int, timestep:
+                int, callback_kwargs: Dict)`.
+            prior_callback_on_step_end_tensor_inputs (`List`, *optional*):
+                The list of tensor inputs for the `prior_callback_on_step_end` function. The tensors specified in the
+                list will be passed as `callback_kwargs` argument. You will only be able to include variables listed in
+                the `._callback_tensor_inputs` attribute of your pipeine class.
+            callback_on_step_end (`Callable`, *optional*):
+                A function that calls at the end of each denoising steps during the inference. The function is called
+                with the following arguments: `callback_on_step_end(self: DiffusionPipeline, step: int, timestep: int,
+                callback_kwargs: Dict)`. `callback_kwargs` will include a list of all tensors as specified by
+                `callback_on_step_end_tensor_inputs`.
+            callback_on_step_end_tensor_inputs (`List`, *optional*):
+                The list of tensor inputs for the `callback_on_step_end` function. The tensors specified in the list
+                will be passed as `callback_kwargs` argument. You will only be able to include variables listed in the
+                `._callback_tensor_inputs` attribute of your pipeine class.
 
         Examples:
 
@@ -246,6 +251,22 @@ class WuerstchenCombinedPipeline(DiffusionPipeline):
             [`~pipelines.ImagePipelineOutput`] or `tuple` [`~pipelines.ImagePipelineOutput`] if `return_dict` is True,
             otherwise a `tuple`. When returning a tuple, the first element is a list with the generated images.
         """
+        prior_kwargs = {}
+        if kwargs.get("prior_callback", None) is not None:
+            prior_kwargs["callback"] = kwargs.pop("prior_callback")
+            deprecate(
+                "prior_callback",
+                "1.0.0",
+                "Passing `prior_callback` as an input argument to `__call__` is deprecated, consider use `prior_callback_on_step_end`",
+            )
+        if kwargs.get("prior_callback_steps", None) is not None:
+            deprecate(
+                "prior_callback_steps",
+                "1.0.0",
+                "Passing `prior_callback_steps` as an input argument to `__call__` is deprecated, consider use `prior_callback_on_step_end`",
+            )
+            prior_kwargs["callback_steps"] = kwargs.pop("prior_callback_steps")
+
         prior_outputs = self.prior_pipe(
             prompt=prompt if prompt_embeds is None else None,
             height=height,
@@ -261,8 +282,9 @@ class WuerstchenCombinedPipeline(DiffusionPipeline):
             latents=latents,
             output_type="pt",
             return_dict=False,
-            callback=prior_callback,
-            callback_steps=prior_callback_steps,
+            callback_on_step_end=prior_callback_on_step_end,
+            callback_on_step_end_tensor_inputs=prior_callback_on_step_end_tensor_inputs,
+            **prior_kwargs,
         )
         image_embeddings = prior_outputs[0]
 
@@ -276,8 +298,9 @@ class WuerstchenCombinedPipeline(DiffusionPipeline):
             generator=generator,
             output_type=output_type,
             return_dict=return_dict,
-            callback=callback,
-            callback_steps=callback_steps,
+            callback_on_step_end=callback_on_step_end,
+            callback_on_step_end_tensor_inputs=callback_on_step_end_tensor_inputs,
+            **kwargs,
         )
 
         return outputs

src/diffusers/pipelines/wuerstchen/pipeline_wuerstchen_prior.py

@@ -14,7 +14,7 @@
 
 from dataclasses import dataclass
 from math import ceil
-from typing import Callable, List, Optional, Union
+from typing import Callable, Dict, List, Optional, Union
 
 import numpy as np
 import torch
@@ -22,11 +22,7 @@ from transformers import CLIPTextModel, CLIPTokenizer
 
 from ...loaders import LoraLoaderMixin
 from ...schedulers import DDPMWuerstchenScheduler
-from ...utils import (
-    BaseOutput,
-    logging,
-    replace_example_docstring,
-)
+from ...utils import BaseOutput, deprecate, logging, replace_example_docstring
 from ...utils.torch_utils import randn_tensor
 from ..pipeline_utils import DiffusionPipeline
 from .modeling_wuerstchen_prior import WuerstchenPrior
@@ -94,6 +90,7 @@ class WuerstchenPriorPipeline(DiffusionPipeline, LoraLoaderMixin):
     unet_name = "prior"
     text_encoder_name = "text_encoder"
     model_cpu_offload_seq = "text_encoder->prior"
+    _callback_tensor_inputs = ["latents", "text_encoder_hidden_states", "negative_prompt_embeds"]
 
     def __init__(
         self,
@@ -264,6 +261,18 @@ class WuerstchenPriorPipeline(DiffusionPipeline, LoraLoaderMixin):
                            In Case you want to provide explicit timesteps, please use the 'timesteps' argument."
             )
 
+    @property
+    def guidance_scale(self):
+        return self._guidance_scale
+
+    @property
+    def do_classifier_free_guidance(self):
+        return self._guidance_scale > 1
+
+    @property
+    def num_timesteps(self):
+        return self._num_timesteps
+
     @torch.no_grad()
     @replace_example_docstring(EXAMPLE_DOC_STRING)
     def __call__(
@@ -282,8 +291,9 @@ class WuerstchenPriorPipeline(DiffusionPipeline, LoraLoaderMixin):
         latents: Optional[torch.FloatTensor] = None,
         output_type: Optional[str] = "pt",
         return_dict: bool = True,
-        callback: Optional[Callable[[int, int, torch.FloatTensor], None]] = None,
-        callback_steps: int = 1,
+        callback_on_step_end: Optional[Callable[[int, int, Dict], None]] = None,
+        callback_on_step_end_tensor_inputs: List[str] = ["latents"],
+        **kwargs,
     ):
         """
         Function invoked when calling the pipeline for generation.
@@ -331,12 +341,15 @@ class WuerstchenPriorPipeline(DiffusionPipeline, LoraLoaderMixin):
                 (`np.array`) or `"pt"` (`torch.Tensor`).
             return_dict (`bool`, *optional*, defaults to `True`):
                 Whether or not to return a [`~pipelines.ImagePipelineOutput`] instead of a plain tuple.
-            callback (`Callable`, *optional*):
-                A function that will be called every `callback_steps` steps during inference. The function will be
-                called with the following arguments: `callback(step: int, timestep: int, latents: torch.FloatTensor)`.
-            callback_steps (`int`, *optional*, defaults to 1):
-                The frequency at which the `callback` function will be called. If not specified, the callback will be
-                called at every step.
+            callback_on_step_end (`Callable`, *optional*):
+                A function that calls at the end of each denoising steps during the inference. The function is called
+                with the following arguments: `callback_on_step_end(self: DiffusionPipeline, step: int, timestep: int,
+                callback_kwargs: Dict)`. `callback_kwargs` will include a list of all tensors as specified by
+                `callback_on_step_end_tensor_inputs`.
+            callback_on_step_end_tensor_inputs (`List`, *optional*):
+                The list of tensor inputs for the `callback_on_step_end` function. The tensors specified in the list
+                will be passed as `callback_kwargs` argument. You will only be able to include variables listed in the
+                `._callback_tensor_inputs` attribute of your pipeine class.
 
         Examples:
 
@@ -346,9 +359,32 @@ class WuerstchenPriorPipeline(DiffusionPipeline, LoraLoaderMixin):
             generated image embeddings.
         """
 
+        callback = kwargs.pop("callback", None)
+        callback_steps = kwargs.pop("callback_steps", None)
+
+        if callback is not None:
+            deprecate(
+                "callback",
+                "1.0.0",
+                "Passing `callback` as an input argument to `__call__` is deprecated, consider use `callback_on_step_end`",
+            )
+        if callback_steps is not None:
+            deprecate(
+                "callback_steps",
+                "1.0.0",
+                "Passing `callback_steps` as an input argument to `__call__` is deprecated, consider use `callback_on_step_end`",
+            )
+
+        if callback_on_step_end_tensor_inputs is not None and not all(
+            k in self._callback_tensor_inputs for k in callback_on_step_end_tensor_inputs
+        ):
+            raise ValueError(
+                f"`callback_on_step_end_tensor_inputs` has to be in {self._callback_tensor_inputs}, but found {[k for k in callback_on_step_end_tensor_inputs if k not in self._callback_tensor_inputs]}"
+            )
+
         # 0. Define commonly used variables
         device = self._execution_device
-        do_classifier_free_guidance = guidance_scale > 1.0
+        self._guidance_scale = guidance_scale
         if prompt is not None and isinstance(prompt, str):
             batch_size = 1
         elif prompt is not None and isinstance(prompt, list):
@@ -363,7 +399,7 @@ class WuerstchenPriorPipeline(DiffusionPipeline, LoraLoaderMixin):
             else:
                 raise TypeError(f"'prompt' must be of type 'list' or 'str', but got {type(prompt)}.")
 
-        if do_classifier_free_guidance:
+        if self.do_classifier_free_guidance:
             if negative_prompt is not None and not isinstance(negative_prompt, list):
                 if isinstance(negative_prompt, str):
                     negative_prompt = [negative_prompt]
@@ -376,7 +412,7 @@ class WuerstchenPriorPipeline(DiffusionPipeline, LoraLoaderMixin):
             prompt,
             negative_prompt,
             num_inference_steps,
-            do_classifier_free_guidance,
+            self.do_classifier_free_guidance,
             prompt_embeds=prompt_embeds,
             negative_prompt_embeds=negative_prompt_embeds,
         )
@@ -386,7 +422,7 @@ class WuerstchenPriorPipeline(DiffusionPipeline, LoraLoaderMixin):
             prompt=prompt,
             device=device,
             num_images_per_prompt=num_images_per_prompt,
-            do_classifier_free_guidance=do_classifier_free_guidance,
+            do_classifier_free_guidance=self.do_classifier_free_guidance,
             negative_prompt=negative_prompt,
             prompt_embeds=prompt_embeds,
             negative_prompt_embeds=negative_prompt_embeds,
@@ -419,21 +455,22 @@ class WuerstchenPriorPipeline(DiffusionPipeline, LoraLoaderMixin):
         latents = self.prepare_latents(effnet_features_shape, dtype, device, generator, latents, self.scheduler)
 
         # 6. Run denoising loop
+        self._num_timesteps = len(timesteps[:-1])
         for i, t in enumerate(self.progress_bar(timesteps[:-1])):
             ratio = t.expand(latents.size(0)).to(dtype)
 
             # 7. Denoise image embeddings
             predicted_image_embedding = self.prior(
-                torch.cat([latents] * 2) if do_classifier_free_guidance else latents,
-                r=torch.cat([ratio] * 2) if do_classifier_free_guidance else ratio,
+                torch.cat([latents] * 2) if self.do_classifier_free_guidance else latents,
+                r=torch.cat([ratio] * 2) if self.do_classifier_free_guidance else ratio,
                 c=text_encoder_hidden_states,
             )
 
             # 8. Check for classifier free guidance and apply it
-            if do_classifier_free_guidance:
+            if self.do_classifier_free_guidance:
                 predicted_image_embedding_text, predicted_image_embedding_uncond = predicted_image_embedding.chunk(2)
                 predicted_image_embedding = torch.lerp(
-                    predicted_image_embedding_uncond, predicted_image_embedding_text, guidance_scale
+                    predicted_image_embedding_uncond, predicted_image_embedding_text, self.guidance_scale
                 )
 
             # 9. Renoise latents to next timestep
@@ -444,6 +481,18 @@ class WuerstchenPriorPipeline(DiffusionPipeline, LoraLoaderMixin):
                 generator=generator,
             ).prev_sample
 
+            if callback_on_step_end is not None:
+                callback_kwargs = {}
+                for k in callback_on_step_end_tensor_inputs:
+                    callback_kwargs[k] = locals()[k]
+                callback_outputs = callback_on_step_end(self, i, t, callback_kwargs)
+
+                latents = callback_outputs.pop("latents", latents)
+                text_encoder_hidden_states = callback_outputs.pop(
+                    "text_encoder_hidden_states", text_encoder_hidden_states
+                )
+                negative_prompt_embeds = callback_outputs.pop("negative_prompt_embeds", negative_prompt_embeds)
+
             if callback is not None and i % callback_steps == 0:
                 step_idx = i // getattr(self.scheduler, "order", 1)
                 callback(step_idx, t, latents)

tests/pipelines/altdiffusion/test_alt_diffusion.py

@@ -27,7 +27,12 @@ from diffusers.pipelines.alt_diffusion.modeling_roberta_series import (
 )
 from diffusers.utils.testing_utils import enable_full_determinism, nightly, require_torch_gpu, torch_device
 
-from ..pipeline_params import TEXT_TO_IMAGE_BATCH_PARAMS, TEXT_TO_IMAGE_IMAGE_PARAMS, TEXT_TO_IMAGE_PARAMS
+from ..pipeline_params import (
+    TEXT_TO_IMAGE_BATCH_PARAMS,
+    TEXT_TO_IMAGE_CALLBACK_CFG_PARAMS,
+    TEXT_TO_IMAGE_IMAGE_PARAMS,
+    TEXT_TO_IMAGE_PARAMS,
+)
 from ..test_pipelines_common import PipelineKarrasSchedulerTesterMixin, PipelineLatentTesterMixin, PipelineTesterMixin
 
 
@@ -42,6 +47,7 @@ class AltDiffusionPipelineFastTests(
     batch_params = TEXT_TO_IMAGE_BATCH_PARAMS
     image_params = TEXT_TO_IMAGE_IMAGE_PARAMS
     image_latents_params = TEXT_TO_IMAGE_IMAGE_PARAMS
+    callback_cfg_params = TEXT_TO_IMAGE_CALLBACK_CFG_PARAMS
 
     def get_dummy_components(self):
         torch.manual_seed(0)