[LoRA] Remove legacy LoRA code and related adjustments (#8316)

* remove legacy code from load_attn_procs.

* finish first draft

* fix more.

* fix more

* add test

* add serialization support.

* fix-copies

* require peft backend for lora tests

* style

* fix test

* fix loading.

* empty

* address benjamin's feedback.

.github/workflows/pr_test_peft_backend.yml

@@ -111,3 +111,21 @@ jobs:
           -s -v \
           --make-reports=tests_${{ matrix.config.report }} \
           tests/lora/
+        python -m pytest -n 4 --max-worker-restart=0 --dist=loadfile \
+          -s -v \
+          --make-reports=tests_models_lora_${{ matrix.config.report }} \
+          tests/models/ -k "lora"
+        
+    
+    - name: Failure short reports
+      if: ${{ failure() }}
+      run: |
+        cat reports/tests_${{ matrix.config.report }}_failures_short.txt
+        cat reports/tests_models_lora_${{ matrix.config.report }}_failures_short.txt
+    
+    - name: Test suite reports artifacts
+      if: ${{ always() }}
+      uses: actions/upload-artifact@v2
+      with:
+        name: pr_${{ matrix.config.report }}_test_reports
+        path: reports
\ No newline at end of file

.github/workflows/push_tests.yml

@@ -189,12 +189,17 @@ jobs:
           -s -v -k "not Flax and not Onnx and not PEFTLoRALoading" \
           --make-reports=tests_peft_cuda \
           tests/lora/
+        python -m pytest -n 1 --max-worker-restart=0 --dist=loadfile \
+          -s -v -k "lora and not Flax and not Onnx and not PEFTLoRALoading" \
+          --make-reports=tests_peft_cuda_models_lora \
+          tests/models/
 
     - name: Failure short reports
       if: ${{ failure() }}
       run: |
         cat reports/tests_peft_cuda_stats.txt
         cat reports/tests_peft_cuda_failures_short.txt
+        cat reports/tests_peft_cuda_models_lora_failures_short.txt
 
     - name: Test suite reports artifacts
       if: ${{ always() }}

src/diffusers/loaders/lora.py

@@ -22,17 +22,14 @@ import torch
 from huggingface_hub import model_info
 from huggingface_hub.constants import HF_HUB_OFFLINE
 from huggingface_hub.utils import validate_hf_hub_args
-from packaging import version
 from torch import nn
 
-from .. import __version__
-from ..models.modeling_utils import _LOW_CPU_MEM_USAGE_DEFAULT, load_state_dict
+from ..models.modeling_utils import load_state_dict
 from ..utils import (
     USE_PEFT_BACKEND,
     _get_model_file,
     convert_state_dict_to_diffusers,
     convert_state_dict_to_peft,
-    convert_unet_state_dict_to_peft,
     delete_adapter_layers,
     get_adapter_name,
     get_peft_kwargs,
@@ -119,13 +116,10 @@ class LoraLoaderMixin:
         if not is_correct_format:
             raise ValueError("Invalid LoRA checkpoint.")
 
-        low_cpu_mem_usage = kwargs.pop("low_cpu_mem_usage", _LOW_CPU_MEM_USAGE_DEFAULT)
-
         self.load_lora_into_unet(
             state_dict,
             network_alphas=network_alphas,
             unet=getattr(self, self.unet_name) if not hasattr(self, "unet") else self.unet,
-            low_cpu_mem_usage=low_cpu_mem_usage,
             adapter_name=adapter_name,
             _pipeline=self,
         )
@@ -136,7 +130,6 @@ class LoraLoaderMixin:
             if not hasattr(self, "text_encoder")
             else self.text_encoder,
             lora_scale=self.lora_scale,
-            low_cpu_mem_usage=low_cpu_mem_usage,
             adapter_name=adapter_name,
             _pipeline=self,
         )
@@ -193,16 +186,8 @@ class LoraLoaderMixin:
                 allowed by Git.
             subfolder (`str`, *optional*, defaults to `""`):
                 The subfolder location of a model file within a larger model repository on the Hub or locally.
-            low_cpu_mem_usage (`bool`, *optional*, defaults to `True` if torch version >= 1.9.0 else `False`):
-                Speed up model loading only loading the pretrained weights and not initializing the weights. This also
-                tries to not use more than 1x model size in CPU memory (including peak memory) while loading the model.
-                Only supported for PyTorch >= 1.9.0. If you are using an older version of PyTorch, setting this
-                argument to `True` will raise an error.
-            mirror (`str`, *optional*):
-                Mirror source to resolve accessibility issues if you're downloading a model in China. We do not
-                guarantee the timeliness or safety of the source, and you should refer to the mirror site for more
-                information.
-
+            weight_name (`str`, *optional*, defaults to None):
+                Name of the serialized state dict file.
         """
         # Load the main state dict first which has the LoRA layers for either of
         # UNet and text encoder or both.
@@ -383,9 +368,7 @@ class LoraLoaderMixin:
         return (is_model_cpu_offload, is_sequential_cpu_offload)
 
     @classmethod
-    def load_lora_into_unet(
-        cls, state_dict, network_alphas, unet, low_cpu_mem_usage=None, adapter_name=None, _pipeline=None
-    ):
+    def load_lora_into_unet(cls, state_dict, network_alphas, unet, adapter_name=None, _pipeline=None):
         """
         This will load the LoRA layers specified in `state_dict` into `unet`.
 
@@ -395,14 +378,11 @@ class LoraLoaderMixin:
                 into the unet or prefixed with an additional `unet` which can be used to distinguish between text
                 encoder lora layers.
             network_alphas (`Dict[str, float]`):
-                See `LoRALinearLayer` for more details.
+                The value of the network alpha used for stable learning and preventing underflow. This value has the
+                same meaning as the `--network_alpha` option in the kohya-ss trainer script. Refer to [this
+                link](https://github.com/darkstorm2150/sd-scripts/blob/main/docs/train_network_README-en.md#execute-learning).
             unet (`UNet2DConditionModel`):
                 The UNet model to load the LoRA layers into.
-            low_cpu_mem_usage (`bool`, *optional*, defaults to `True` if torch version >= 1.9.0 else `False`):
-                Speed up model loading only loading the pretrained weights and not initializing the weights. This also
-                tries to not use more than 1x model size in CPU memory (including peak memory) while loading the model.
-                Only supported for PyTorch >= 1.9.0. If you are using an older version of PyTorch, setting this
-                argument to `True` will raise an error.
             adapter_name (`str`, *optional*):
                 Adapter name to be used for referencing the loaded adapter model. If not specified, it will use
                 `default_{i}` where i is the total number of adapters being loaded.
@@ -410,93 +390,17 @@ class LoraLoaderMixin:
         if not USE_PEFT_BACKEND:
             raise ValueError("PEFT backend is required for this method.")
 
-        from peft import LoraConfig, inject_adapter_in_model, set_peft_model_state_dict
-
-        low_cpu_mem_usage = low_cpu_mem_usage if low_cpu_mem_usage is not None else _LOW_CPU_MEM_USAGE_DEFAULT
         # If the serialization format is new (introduced in https://github.com/huggingface/diffusers/pull/2918),
         # then the `state_dict` keys should have `cls.unet_name` and/or `cls.text_encoder_name` as
         # their prefixes.
         keys = list(state_dict.keys())
+        only_text_encoder = all(key.startswith(cls.text_encoder_name) for key in keys)
 
-        if all(key.startswith(cls.unet_name) or key.startswith(cls.text_encoder_name) for key in keys):
+        if any(key.startswith(cls.unet_name) for key in keys) and not only_text_encoder:
             # Load the layers corresponding to UNet.
             logger.info(f"Loading {cls.unet_name}.")
-
-            unet_keys = [k for k in keys if k.startswith(cls.unet_name)]
-            state_dict = {k.replace(f"{cls.unet_name}.", ""): v for k, v in state_dict.items() if k in unet_keys}
-
-            if network_alphas is not None:
-                alpha_keys = [k for k in network_alphas.keys() if k.startswith(cls.unet_name)]
-                network_alphas = {
-                    k.replace(f"{cls.unet_name}.", ""): v for k, v in network_alphas.items() if k in alpha_keys
-                }
-
-        else:
-            # Otherwise, we're dealing with the old format. This means the `state_dict` should only
-            # contain the module names of the `unet` as its keys WITHOUT any prefix.
-            if not USE_PEFT_BACKEND:
-                warn_message = "You have saved the LoRA weights using the old format. To convert the old LoRA weights to the new format, you can first load them in a dictionary and then create a new dictionary like the following: `new_state_dict = {f'unet.{module_name}': params for module_name, params in old_state_dict.items()}`."
-                logger.warning(warn_message)
-
-        if len(state_dict.keys()) > 0:
-            if adapter_name in getattr(unet, "peft_config", {}):
-                raise ValueError(
-                    f"Adapter name {adapter_name} already in use in the Unet - please select a new adapter name."
-                )
-
-            state_dict = convert_unet_state_dict_to_peft(state_dict)
-
-            if network_alphas is not None:
-                # The alphas state dict have the same structure as Unet, thus we convert it to peft format using
-                # `convert_unet_state_dict_to_peft` method.
-                network_alphas = convert_unet_state_dict_to_peft(network_alphas)
-
-            rank = {}
-            for key, val in state_dict.items():
-                if "lora_B" in key:
-                    rank[key] = val.shape[1]
-
-            lora_config_kwargs = get_peft_kwargs(rank, network_alphas, state_dict, is_unet=True)
-            if "use_dora" in lora_config_kwargs:
-                if lora_config_kwargs["use_dora"]:
-                    if is_peft_version("<", "0.9.0"):
-                        raise ValueError(
-                            "You need `peft` 0.9.0 at least to use DoRA-enabled LoRAs. Please upgrade your installation of `peft`."
-                        )
-                else:
-                    if is_peft_version("<", "0.9.0"):
-                        lora_config_kwargs.pop("use_dora")
-            lora_config = LoraConfig(**lora_config_kwargs)
-
-            # adapter_name
-            if adapter_name is None:
-                adapter_name = get_adapter_name(unet)
-
-            # In case the pipeline has been already offloaded to CPU - temporarily remove the hooks
-            # otherwise loading LoRA weights will lead to an error
-            is_model_cpu_offload, is_sequential_cpu_offload = cls._optionally_disable_offloading(_pipeline)
-
-            inject_adapter_in_model(lora_config, unet, adapter_name=adapter_name)
-            incompatible_keys = set_peft_model_state_dict(unet, state_dict, adapter_name)
-
-            if incompatible_keys is not None:
-                # check only for unexpected keys
-                unexpected_keys = getattr(incompatible_keys, "unexpected_keys", None)
-                if unexpected_keys:
-                    logger.warning(
-                        f"Loading adapter weights from state_dict led to unexpected keys not found in the model: "
-                        f" {unexpected_keys}. "
-                    )
-
-            # Offload back.
-            if is_model_cpu_offload:
-                _pipeline.enable_model_cpu_offload()
-            elif is_sequential_cpu_offload:
-                _pipeline.enable_sequential_cpu_offload()
-            # Unsafe code />
-
             unet.load_attn_procs(
-            state_dict, network_alphas=network_alphas, low_cpu_mem_usage=low_cpu_mem_usage, _pipeline=_pipeline
+                state_dict, network_alphas=network_alphas, adapter_name=adapter_name, _pipeline=_pipeline
             )
 
     @classmethod
@@ -507,7 +411,6 @@ class LoraLoaderMixin:
         text_encoder,
         prefix=None,
         lora_scale=1.0,
-        low_cpu_mem_usage=None,
         adapter_name=None,
         _pipeline=None,
     ):
@@ -527,11 +430,6 @@ class LoraLoaderMixin:
             lora_scale (`float`):
                 How much to scale the output of the lora linear layer before it is added with the output of the regular
                 lora layer.
-            low_cpu_mem_usage (`bool`, *optional*, defaults to `True` if torch version >= 1.9.0 else `False`):
-                Speed up model loading only loading the pretrained weights and not initializing the weights. This also
-                tries to not use more than 1x model size in CPU memory (including peak memory) while loading the model.
-                Only supported for PyTorch >= 1.9.0. If you are using an older version of PyTorch, setting this
-                argument to `True` will raise an error.
             adapter_name (`str`, *optional*):
                 Adapter name to be used for referencing the loaded adapter model. If not specified, it will use
                 `default_{i}` where i is the total number of adapters being loaded.
@@ -541,8 +439,6 @@ class LoraLoaderMixin:
 
         from peft import LoraConfig
 
-        low_cpu_mem_usage = low_cpu_mem_usage if low_cpu_mem_usage is not None else _LOW_CPU_MEM_USAGE_DEFAULT
-
         # If the serialization format is new (introduced in https://github.com/huggingface/diffusers/pull/2918),
         # then the `state_dict` keys should have `self.unet_name` and/or `self.text_encoder_name` as
         # their prefixes.
@@ -625,9 +521,7 @@ class LoraLoaderMixin:
                 # Unsafe code />
 
     @classmethod
-    def load_lora_into_transformer(
-        cls, state_dict, network_alphas, transformer, low_cpu_mem_usage=None, adapter_name=None, _pipeline=None
-    ):
+    def load_lora_into_transformer(cls, state_dict, network_alphas, transformer, adapter_name=None, _pipeline=None):
         """
         This will load the LoRA layers specified in `state_dict` into `transformer`.
 
@@ -640,19 +534,12 @@ class LoraLoaderMixin:
                 See `LoRALinearLayer` for more details.
             unet (`UNet2DConditionModel`):
                 The UNet model to load the LoRA layers into.
-            low_cpu_mem_usage (`bool`, *optional*, defaults to `True` if torch version >= 1.9.0 else `False`):
-                Speed up model loading only loading the pretrained weights and not initializing the weights. This also
-                tries to not use more than 1x model size in CPU memory (including peak memory) while loading the model.
-                Only supported for PyTorch >= 1.9.0. If you are using an older version of PyTorch, setting this
-                argument to `True` will raise an error.
             adapter_name (`str`, *optional*):
                 Adapter name to be used for referencing the loaded adapter model. If not specified, it will use
                 `default_{i}` where i is the total number of adapters being loaded.
         """
         from peft import LoraConfig, inject_adapter_in_model, set_peft_model_state_dict
 
-        low_cpu_mem_usage = low_cpu_mem_usage if low_cpu_mem_usage is not None else _LOW_CPU_MEM_USAGE_DEFAULT
-
         keys = list(state_dict.keys())
 
         transformer_keys = [k for k in keys if k.startswith(cls.transformer_name)]
@@ -846,22 +733,11 @@ class LoraLoaderMixin:
         >>> ...
         ```
         """
-        unet = getattr(self, self.unet_name) if not hasattr(self, "unet") else self.unet
-
         if not USE_PEFT_BACKEND:
-            if version.parse(__version__) > version.parse("0.23"):
-                logger.warning(
-                    "You are using `unload_lora_weights` to disable and unload lora weights. If you want to iteratively enable and disable adapter weights,"
-                    "you can use `pipe.enable_lora()` or `pipe.disable_lora()`. After installing the latest version of PEFT."
-                )
+            raise ValueError("PEFT backend is required for this method.")
 
-            for _, module in unet.named_modules():
-                if hasattr(module, "set_lora_layer"):
-                    module.set_lora_layer(None)
-        else:
-            recurse_remove_peft_layers(unet)
-            if hasattr(unet, "peft_config"):
-                del unet.peft_config
+        unet = getattr(self, self.unet_name) if not hasattr(self, "unet") else self.unet
+        unet.unload_lora()
 
         # Safe to call the following regardless of LoRA.
         self._remove_text_encoder_monkey_patch()

src/diffusers/models/unets/unet_2d_condition.py

@@ -903,17 +903,6 @@ class UNet2DConditionModel(
         if self.original_attn_processors is not None:
             self.set_attn_processor(self.original_attn_processors)
 
-    def unload_lora(self):
-        """Unloads LoRA weights."""
-        deprecate(
-            "unload_lora",
-            "0.28.0",
-            "Calling `unload_lora()` is deprecated and will be removed in a future version. Please install `peft` and then call `disable_adapters().",
-        )
-        for module in self.modules():
-            if hasattr(module, "set_lora_layer"):
-                module.set_lora_layer(None)
-
     def get_time_embed(
         self, sample: torch.Tensor, timestep: Union[torch.Tensor, float, int]
     ) -> Optional[torch.Tensor]:

src/diffusers/models/unets/unet_3d_condition.py

@@ -22,7 +22,7 @@ import torch.utils.checkpoint
 
 from ...configuration_utils import ConfigMixin, register_to_config
 from ...loaders import UNet2DConditionLoadersMixin
-from ...utils import BaseOutput, deprecate, logging
+from ...utils import BaseOutput, logging
 from ..activations import get_activation
 from ..attention_processor import (
     ADDED_KV_ATTENTION_PROCESSORS,
@@ -546,18 +546,6 @@ class UNet3DConditionModel(ModelMixin, ConfigMixin, UNet2DConditionLoadersMixin)
         if self.original_attn_processors is not None:
             self.set_attn_processor(self.original_attn_processors)
 
-    # Copied from diffusers.models.unets.unet_2d_condition.UNet2DConditionModel.unload_lora
-    def unload_lora(self):
-        """Unloads LoRA weights."""
-        deprecate(
-            "unload_lora",
-            "0.28.0",
-            "Calling `unload_lora()` is deprecated and will be removed in a future version. Please install `peft` and then call `disable_adapters().",
-        )
-        for module in self.modules():
-            if hasattr(module, "set_lora_layer"):
-                module.set_lora_layer(None)
-
     def forward(
         self,
         sample: torch.Tensor,

tests/models/unets/test_models_unet_2d_condition.py

@@ -37,7 +37,9 @@ from diffusers.utils.testing_utils import (
     backend_empty_cache,
     enable_full_determinism,
     floats_tensor,
+    is_peft_available,
     load_hf_numpy,
+    require_peft_backend,
     require_torch_accelerator,
     require_torch_accelerator_with_fp16,
     require_torch_accelerator_with_training,
@@ -51,11 +53,38 @@ from diffusers.utils.testing_utils import (
 from ..test_modeling_common import ModelTesterMixin, UNetTesterMixin
 
 
+if is_peft_available():
+    from peft import LoraConfig
+    from peft.tuners.tuners_utils import BaseTunerLayer
+
+
 logger = logging.get_logger(__name__)
 
 enable_full_determinism()
 
 
+def get_unet_lora_config():
+    rank = 4
+    unet_lora_config = LoraConfig(
+        r=rank,
+        lora_alpha=rank,
+        target_modules=["to_q", "to_k", "to_v", "to_out.0"],
+        init_lora_weights=False,
+        use_dora=False,
+    )
+    return unet_lora_config
+
+
+def check_if_lora_correctly_set(model) -> bool:
+    """
+    Checks if the LoRA layers are correctly set with peft
+    """
+    for module in model.modules():
+        if isinstance(module, BaseTunerLayer):
+            return True
+    return False
+
+
 def create_ip_adapter_state_dict(model):
     # "ip_adapter" (cross-attention weights)
     ip_cross_attn_state_dict = {}
@@ -1005,6 +1034,65 @@ class UNet2DConditionModelTests(ModelTesterMixin, UNetTesterMixin, unittest.Test
         assert sample2.allclose(sample5, atol=1e-4, rtol=1e-4)
         assert sample2.allclose(sample6, atol=1e-4, rtol=1e-4)
 
+    @require_peft_backend
+    def test_lora(self):
+        init_dict, inputs_dict = self.prepare_init_args_and_inputs_for_common()
+        model = self.model_class(**init_dict)
+        model.to(torch_device)
+
+        # forward pass without LoRA
+        with torch.no_grad():
+            non_lora_sample = model(**inputs_dict).sample
+
+        unet_lora_config = get_unet_lora_config()
+        model.add_adapter(unet_lora_config)
+
+        assert check_if_lora_correctly_set(model), "Lora not correctly set in UNet."
+
+        # forward pass with LoRA
+        with torch.no_grad():
+            lora_sample = model(**inputs_dict).sample
+
+        assert not torch.allclose(
+            non_lora_sample, lora_sample, atol=1e-4, rtol=1e-4
+        ), "LoRA injected UNet should produce different results."
+
+    @require_peft_backend
+    def test_lora_serialization(self):
+        init_dict, inputs_dict = self.prepare_init_args_and_inputs_for_common()
+        model = self.model_class(**init_dict)
+        model.to(torch_device)
+
+        # forward pass without LoRA
+        with torch.no_grad():
+            non_lora_sample = model(**inputs_dict).sample
+
+        unet_lora_config = get_unet_lora_config()
+        model.add_adapter(unet_lora_config)
+
+        assert check_if_lora_correctly_set(model), "Lora not correctly set in UNet."
+
+        # forward pass with LoRA
+        with torch.no_grad():
+            lora_sample_1 = model(**inputs_dict).sample
+
+        with tempfile.TemporaryDirectory() as tmpdirname:
+            model.save_attn_procs(tmpdirname)
+            model.unload_lora()
+            model.load_attn_procs(os.path.join(tmpdirname, "pytorch_lora_weights.safetensors"))
+
+            assert check_if_lora_correctly_set(model), "Lora not correctly set in UNet."
+
+            with torch.no_grad():
+                lora_sample_2 = model(**inputs_dict).sample
+
+        assert not torch.allclose(
+            non_lora_sample, lora_sample_1, atol=1e-4, rtol=1e-4
+        ), "LoRA injected UNet should produce different results."
+        assert torch.allclose(
+            lora_sample_1, lora_sample_2, atol=1e-4, rtol=1e-4
+        ), "Loading from a saved checkpoint should produce identical results."
+
 
 @slow
 class UNet2DConditionModelIntegrationTests(unittest.TestCase):