Test error raised when loading normal and expanding loras together in Flux (#10188)

* add test for expanding lora and normal lora error

* Update tests/lora/test_lora_layers_flux.py

* fix things.

* Update src/diffusers/loaders/peft.py

---------

Co-authored-by: Sayak Paul <spsayakpaul@gmail.com>

src/diffusers/loaders/lora_pipeline.py

@@ -2337,12 +2337,19 @@ class FluxLoraLoaderMixin(LoraBaseMixin):
                         f"this please open an issue at https://github.com/huggingface/diffusers/issues."
                     )
 
-                logger.debug(
+                debug_message = (
                     f'Expanding the nn.Linear input/output features for module="{name}" because the provided LoRA '
                     f"checkpoint contains higher number of features than expected. The number of input_features will be "
-                    f"expanded from {module_in_features} to {in_features}, and the number of output features will be "
-                    f"expanded from {module_out_features} to {out_features}."
+                    f"expanded from {module_in_features} to {in_features}"
                 )
+                if module_out_features != out_features:
+                    debug_message += (
+                        ", and the number of output features will be "
+                        f"expanded from {module_out_features} to {out_features}."
+                    )
+                else:
+                    debug_message += "."
+                logger.debug(debug_message)
 
                 has_param_with_shape_update = True
                 parent_module_name, _, current_module_name = name.rpartition(".")

src/diffusers/loaders/peft.py

@@ -205,6 +205,7 @@ class PeftAdapterMixin:
                 weights.
         """
         from peft import LoraConfig, inject_adapter_in_model, set_peft_model_state_dict
+        from peft.tuners.tuners_utils import BaseTunerLayer
 
         cache_dir = kwargs.pop("cache_dir", None)
         force_download = kwargs.pop("force_download", False)
@@ -316,8 +317,22 @@ class PeftAdapterMixin:
             if is_peft_version(">=", "0.13.1"):
                 peft_kwargs["low_cpu_mem_usage"] = low_cpu_mem_usage
 
-            inject_adapter_in_model(lora_config, self, adapter_name=adapter_name, **peft_kwargs)
-            incompatible_keys = set_peft_model_state_dict(self, state_dict, adapter_name, **peft_kwargs)
+            # To handle scenarios where we cannot successfully set state dict. If it's unsucessful,
+            # we should also delete the `peft_config` associated to the `adapter_name`.
+            try:
+                inject_adapter_in_model(lora_config, self, adapter_name=adapter_name, **peft_kwargs)
+                incompatible_keys = set_peft_model_state_dict(self, state_dict, adapter_name, **peft_kwargs)
+            except RuntimeError as e:
+                for module in self.modules():
+                    if isinstance(module, BaseTunerLayer):
+                        active_adapters = module.active_adapters
+                        for active_adapter in active_adapters:
+                            if adapter_name in active_adapter:
+                                module.delete_adapter(adapter_name)
+
+                self.peft_config.pop(adapter_name)
+                logger.error(f"Loading {adapter_name} was unsucessful with the following error: \n{e}")
+                raise
 
             warn_msg = ""
             if incompatible_keys is not None:

tests/lora/test_lora_layers_flux.py

@@ -430,6 +430,122 @@ class FluxControlLoRATests(unittest.TestCase, PeftLoraLoaderMixinTests):
         self.assertTrue(not np.allclose(original_output, lora_output_diff_alpha, atol=1e-3, rtol=1e-3))
         self.assertTrue(not np.allclose(lora_output_diff_alpha, lora_output_same_rank, atol=1e-3, rtol=1e-3))
 
+    def test_lora_expanding_shape_with_normal_lora_raises_error(self):
+        # TODO: This test checks if an error is raised when a lora expands shapes (like control loras) but
+        # another lora with correct shapes is loaded. This is not supported at the moment and should raise an error.
+        # When we do support it, this test should be removed. Context: https://github.com/huggingface/diffusers/issues/10180
+        components, _, _ = self.get_dummy_components(FlowMatchEulerDiscreteScheduler)
+
+        # Change the transformer config to mimic a real use case.
+        num_channels_without_control = 4
+        transformer = FluxTransformer2DModel.from_config(
+            components["transformer"].config, in_channels=num_channels_without_control
+        ).to(torch_device)
+        components["transformer"] = transformer
+
+        pipe = self.pipeline_class(**components)
+        pipe = pipe.to(torch_device)
+        pipe.set_progress_bar_config(disable=None)
+
+        logger = logging.get_logger("diffusers.loaders.lora_pipeline")
+        logger.setLevel(logging.DEBUG)
+
+        out_features, in_features = pipe.transformer.x_embedder.weight.shape
+        rank = 4
+
+        shape_expander_lora_A = torch.nn.Linear(2 * in_features, rank, bias=False)
+        shape_expander_lora_B = torch.nn.Linear(rank, out_features, bias=False)
+        lora_state_dict = {
+            "transformer.x_embedder.lora_A.weight": shape_expander_lora_A.weight,
+            "transformer.x_embedder.lora_B.weight": shape_expander_lora_B.weight,
+        }
+        with CaptureLogger(logger) as cap_logger:
+            pipe.load_lora_weights(lora_state_dict, "adapter-1")
+
+        self.assertTrue(check_if_lora_correctly_set(pipe.transformer), "Lora not correctly set in denoiser")
+        self.assertTrue(pipe.get_active_adapters() == ["adapter-1"])
+        self.assertTrue(pipe.transformer.x_embedder.weight.data.shape[1] == 2 * in_features)
+        self.assertTrue(pipe.transformer.config.in_channels == 2 * in_features)
+        self.assertTrue(cap_logger.out.startswith("Expanding the nn.Linear input/output features for module"))
+
+        _, _, inputs = self.get_dummy_inputs(with_generator=False)
+        lora_output = pipe(**inputs, generator=torch.manual_seed(0))[0]
+
+        normal_lora_A = torch.nn.Linear(in_features, rank, bias=False)
+        normal_lora_B = torch.nn.Linear(rank, out_features, bias=False)
+        lora_state_dict = {
+            "transformer.x_embedder.lora_A.weight": normal_lora_A.weight,
+            "transformer.x_embedder.lora_B.weight": normal_lora_B.weight,
+        }
+
+        # The first lora expanded the input features of x_embedder. Here, we are trying to load a lora with the correct
+        # input features before expansion. This should raise an error about the weight shapes being incompatible.
+        self.assertRaisesRegex(
+            RuntimeError,
+            "size mismatch for x_embedder.lora_A.adapter-2.weight",
+            pipe.load_lora_weights,
+            lora_state_dict,
+            "adapter-2",
+        )
+        # We should have `adapter-1` as the only adapter.
+        self.assertTrue(pipe.get_active_adapters() == ["adapter-1"])
+
+        # Check if the output is the same after lora loading error
+        lora_output_after_error = pipe(**inputs, generator=torch.manual_seed(0))[0]
+        self.assertTrue(np.allclose(lora_output, lora_output_after_error, atol=1e-3, rtol=1e-3))
+
+        # Test the opposite case where the first lora has the correct input features and the second lora has expanded input features.
+        # This should raise a runtime error on input shapes being incompatible. But it doesn't. This is because PEFT renames the
+        # original layers as `base_layer` and the lora layers with the adapter names. This makes our logic to check if a lora
+        # weight is compatible with the current model inadequate. This should be addressed when attempting support for
+        # https://github.com/huggingface/diffusers/issues/10180 (TODO)
+        components, _, _ = self.get_dummy_components(FlowMatchEulerDiscreteScheduler)
+        # Change the transformer config to mimic a real use case.
+        num_channels_without_control = 4
+        transformer = FluxTransformer2DModel.from_config(
+            components["transformer"].config, in_channels=num_channels_without_control
+        ).to(torch_device)
+        components["transformer"] = transformer
+
+        pipe = self.pipeline_class(**components)
+        pipe = pipe.to(torch_device)
+        pipe.set_progress_bar_config(disable=None)
+
+        logger = logging.get_logger("diffusers.loaders.lora_pipeline")
+        logger.setLevel(logging.DEBUG)
+
+        out_features, in_features = pipe.transformer.x_embedder.weight.shape
+        rank = 4
+
+        lora_state_dict = {
+            "transformer.x_embedder.lora_A.weight": normal_lora_A.weight,
+            "transformer.x_embedder.lora_B.weight": normal_lora_B.weight,
+        }
+
+        with CaptureLogger(logger) as cap_logger:
+            pipe.load_lora_weights(lora_state_dict, "adapter-1")
+            self.assertTrue(check_if_lora_correctly_set(pipe.transformer), "Lora not correctly set in denoiser")
+
+        self.assertTrue(pipe.transformer.x_embedder.weight.data.shape[1] == in_features)
+        self.assertTrue(pipe.transformer.config.in_channels == in_features)
+        self.assertFalse(cap_logger.out.startswith("Expanding the nn.Linear input/output features for module"))
+
+        lora_state_dict = {
+            "transformer.x_embedder.lora_A.weight": shape_expander_lora_A.weight,
+            "transformer.x_embedder.lora_B.weight": shape_expander_lora_B.weight,
+        }
+
+        # We should check for input shapes being incompatible here. But because above mentioned issue is
+        # not a supported use case, and because of the PEFT renaming, we will currently have a shape
+        # mismatch error.
+        self.assertRaisesRegex(
+            RuntimeError,
+            "size mismatch for x_embedder.lora_A.adapter-2.weight",
+            pipe.load_lora_weights,
+            lora_state_dict,
+            "adapter-2",
+        )
+
     @unittest.skip("Not supported in Flux.")
     def test_simple_inference_with_text_denoiser_block_scale_for_all_dict_options(self):
         pass