Improve error msg when using bitsandbytes (#31350)

improve error msg when using bnb

src/transformers/quantizers/quantizer_bnb_4bit.py

@@ -60,10 +60,11 @@ class Bnb4BitHfQuantizer(HfQuantizer):
     def validate_environment(self, *args, **kwargs):
         if not torch.cuda.is_available():
             raise RuntimeError("No GPU found. A GPU is needed for quantization.")
-        if not (is_accelerate_available() and is_bitsandbytes_available()):
+        if not is_accelerate_available():
+            raise ImportError("Using `bitsandbytes` 4-bit quantization requires Accelerate: `pip install accelerate`")
+        if not is_bitsandbytes_available():
             raise ImportError(
-                "Using `bitsandbytes` 8-bit quantization requires Accelerate: `pip install accelerate` "
-                "and the latest version of bitsandbytes: `pip install -U bitsandbytes`"
+                "Using `bitsandbytes` 4-bit quantization requires the latest version of bitsandbytes: `pip install -U bitsandbytes`"
             )
 
         if kwargs.get("from_tf", False) or kwargs.get("from_flax", False):

src/transformers/quantizers/quantizer_bnb_8bit.py

@@ -61,10 +61,11 @@ class Bnb8BitHfQuantizer(HfQuantizer):
         if not torch.cuda.is_available():
             raise RuntimeError("No GPU found. A GPU is needed for quantization.")
 
-        if not (is_accelerate_available() and is_bitsandbytes_available()):
+        if not is_accelerate_available():
+            raise ImportError("Using `bitsandbytes` 8-bit quantization requires Accelerate: `pip install accelerate`")
+        if not is_bitsandbytes_available():
             raise ImportError(
-                "Using `bitsandbytes` 8-bit quantization requires Accelerate: `pip install accelerate` "
-                "and the latest version of bitsandbytes: `pip install -U bitsandbytes`"
+                "Using `bitsandbytes` 8-bit quantization requires the latest version of bitsandbytes: `pip install -U bitsandbytes`"
             )
 
         if kwargs.get("from_tf", False) or kwargs.get("from_flax", False):