[FLUX] support LoRA (#9057)

* feat: lora support for Flux.

add tests

fix imports

major fixes.

* fix

fixes

final fixes?

* fix

* remove is_peft_available.

Author: sayakpaul

src/diffusers/loaders/__init__.py

@@ -66,6 +66,7 @@ def text_encoder_attn_modules(text_encoder):
             "SD3LoraLoaderMixin",
             "StableDiffusionXLLoraLoaderMixin",
             "LoraLoaderMixin",
+            "FluxLoraLoaderMixin",
         ]
         _import_structure["textual_inversion"] = ["TextualInversionLoaderMixin"]
         _import_structure["ip_adapter"] = ["IPAdapterMixin"]
@@ -83,6 +84,7 @@ def text_encoder_attn_modules(text_encoder):
             from .ip_adapter import IPAdapterMixin
             from .lora_pipeline import (
                 AmusedLoraLoaderMixin,
+                FluxLoraLoaderMixin,
                 LoraLoaderMixin,
                 SD3LoraLoaderMixin,
                 StableDiffusionLoraLoaderMixin,

src/diffusers/loaders/lora_pipeline.py

@@ -32,6 +32,7 @@
     "UNet2DConditionModel": _maybe_expand_lora_scales,
     "UNetMotionModel": _maybe_expand_lora_scales,
     "SD3Transformer2DModel": lambda model_cls, weights: weights,
+    "FluxTransformer2DModel": lambda model_cls, weights: weights,
 }
 
 

src/diffusers/loaders/peft.py

@@ -20,7 +20,7 @@
 from transformers import CLIPTextModel, CLIPTokenizer, T5EncoderModel, T5TokenizerFast
 
 from ...image_processor import VaeImageProcessor
-from ...loaders import SD3LoraLoaderMixin
+from ...loaders import FluxLoraLoaderMixin
 from ...models.autoencoders import AutoencoderKL
 from ...models.transformers import FluxTransformer2DModel
 from ...schedulers import FlowMatchEulerDiscreteScheduler
@@ -137,7 +137,7 @@ def retrieve_timesteps(
     return timesteps, num_inference_steps
 
 
-class FluxPipeline(DiffusionPipeline, SD3LoraLoaderMixin):
+class FluxPipeline(DiffusionPipeline, FluxLoraLoaderMixin):
     r"""
     The Flux pipeline for text-to-image generation.
 
@@ -321,7 +321,7 @@ def encode_prompt(
 
         # set lora scale so that monkey patched LoRA
         # function of text encoder can correctly access it
-        if lora_scale is not None and isinstance(self, SD3LoraLoaderMixin):
+        if lora_scale is not None and isinstance(self, FluxLoraLoaderMixin):
             self._lora_scale = lora_scale
 
             # dynamically adjust the LoRA scale
@@ -354,12 +354,12 @@ def encode_prompt(
             )
 
         if self.text_encoder is not None:
-            if isinstance(self, SD3LoraLoaderMixin) and USE_PEFT_BACKEND:
+            if isinstance(self, FluxLoraLoaderMixin) and USE_PEFT_BACKEND:
                 # Retrieve the original scale by scaling back the LoRA layers
                 unscale_lora_layers(self.text_encoder, lora_scale)
 
         if self.text_encoder_2 is not None:
-            if isinstance(self, SD3LoraLoaderMixin) and USE_PEFT_BACKEND:
+            if isinstance(self, FluxLoraLoaderMixin) and USE_PEFT_BACKEND:
                 # Retrieve the original scale by scaling back the LoRA layers
                 unscale_lora_layers(self.text_encoder_2, lora_scale)
 

src/diffusers/pipelines/flux/pipeline_flux.py

@@ -0,0 +1,92 @@
+# coding=utf-8
+# Copyright 2024 HuggingFace Inc.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# 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.
+import sys
+import unittest
+
+import torch
+from transformers import AutoTokenizer, CLIPTextModel, CLIPTokenizer, T5EncoderModel
+
+from diffusers import FlowMatchEulerDiscreteScheduler, FluxPipeline, FluxTransformer2DModel
+from diffusers.utils.testing_utils import floats_tensor, require_peft_backend
+
+
+sys.path.append(".")
+
+from utils import PeftLoraLoaderMixinTests  # noqa: E402
+
+
+@require_peft_backend
+class FluxLoRATests(unittest.TestCase, PeftLoraLoaderMixinTests):
+    pipeline_class = FluxPipeline
+    scheduler_cls = FlowMatchEulerDiscreteScheduler()
+    scheduler_kwargs = {}
+    uses_flow_matching = True
+    transformer_kwargs = {
+        "patch_size": 1,
+        "in_channels": 4,
+        "num_layers": 1,
+        "num_single_layers": 1,
+        "attention_head_dim": 16,
+        "num_attention_heads": 2,
+        "joint_attention_dim": 32,
+        "pooled_projection_dim": 32,
+        "axes_dims_rope": [4, 4, 8],
+    }
+    transformer_cls = FluxTransformer2DModel
+    vae_kwargs = {
+        "sample_size": 32,
+        "in_channels": 3,
+        "out_channels": 3,
+        "block_out_channels": (4,),
+        "layers_per_block": 1,
+        "latent_channels": 1,
+        "norm_num_groups": 1,
+        "use_quant_conv": False,
+        "use_post_quant_conv": False,
+        "shift_factor": 0.0609,
+        "scaling_factor": 1.5035,
+    }
+    has_two_text_encoders = True
+    tokenizer_cls, tokenizer_id = CLIPTokenizer, "peft-internal-testing/tiny-clip-text-2"
+    tokenizer_2_cls, tokenizer_2_id = AutoTokenizer, "hf-internal-testing/tiny-random-t5"
+    text_encoder_cls, text_encoder_id = CLIPTextModel, "peft-internal-testing/tiny-clip-text-2"
+    text_encoder_2_cls, text_encoder_2_id = T5EncoderModel, "hf-internal-testing/tiny-random-t5"
+
+    @property
+    def output_shape(self):
+        return (1, 8, 8, 3)
+
+    def get_dummy_inputs(self, with_generator=True):
+        batch_size = 1
+        sequence_length = 10
+        num_channels = 4
+        sizes = (32, 32)
+
+        generator = torch.manual_seed(0)
+        noise = floats_tensor((batch_size, num_channels) + sizes)
+        input_ids = torch.randint(1, sequence_length, size=(batch_size, sequence_length), generator=generator)
+
+        pipeline_inputs = {
+            "prompt": "A painting of a squirrel eating a burger",
+            "num_inference_steps": 4,
+            "guidance_scale": 0.0,
+            "height": 8,
+            "width": 8,
+            "output_type": "np",
+        }
+        if with_generator:
+            pipeline_inputs.update({"generator": generator})
+
+        return noise, input_ids, pipeline_inputs

tests/lora/test_lora_layers_flux.py

@@ -22,6 +22,7 @@
 from huggingface_hub import hf_hub_download
 from huggingface_hub.repocard import RepoCard
 from safetensors.torch import load_file
+from transformers import CLIPTextModel, CLIPTokenizer
 
 from diffusers import (
     AutoPipelineForImage2Image,
@@ -80,6 +81,12 @@ class StableDiffusionLoRATests(PeftLoraLoaderMixinTests, unittest.TestCase):
         "up_block_types": ["UpDecoderBlock2D", "UpDecoderBlock2D"],
         "latent_channels": 4,
     }
+    text_encoder_cls, text_encoder_id = CLIPTextModel, "peft-internal-testing/tiny-clip-text-2"
+    tokenizer_cls, tokenizer_id = CLIPTokenizer, "peft-internal-testing/tiny-clip-text-2"
+
+    @property
+    def output_shape(self):
+        return (1, 64, 64, 3)
 
     def setUp(self):
         super().setUp()

tests/lora/test_lora_layers_sd.py

@@ -15,10 +15,9 @@
 import sys
 import unittest
 
-from diffusers import (
-    FlowMatchEulerDiscreteScheduler,
-    StableDiffusion3Pipeline,
-)
+from transformers import AutoTokenizer, CLIPTextModelWithProjection, CLIPTokenizer, T5EncoderModel
+
+from diffusers import FlowMatchEulerDiscreteScheduler, SD3Transformer2DModel, StableDiffusion3Pipeline
 from diffusers.utils.testing_utils import is_peft_available, require_peft_backend, require_torch_gpu, torch_device
 
 
@@ -35,6 +34,7 @@ class SD3LoRATests(unittest.TestCase, PeftLoraLoaderMixinTests):
     pipeline_class = StableDiffusion3Pipeline
     scheduler_cls = FlowMatchEulerDiscreteScheduler()
     scheduler_kwargs = {}
+    uses_flow_matching = True
     transformer_kwargs = {
         "sample_size": 32,
         "patch_size": 1,
@@ -47,6 +47,7 @@ class SD3LoRATests(unittest.TestCase, PeftLoraLoaderMixinTests):
         "pooled_projection_dim": 64,
         "out_channels": 4,
     }
+    transformer_cls = SD3Transformer2DModel
     vae_kwargs = {
         "sample_size": 32,
         "in_channels": 3,
@@ -61,6 +62,16 @@ class SD3LoRATests(unittest.TestCase, PeftLoraLoaderMixinTests):
         "scaling_factor": 1.5035,
     }
     has_three_text_encoders = True
+    tokenizer_cls, tokenizer_id = CLIPTokenizer, "hf-internal-testing/tiny-random-clip"
+    tokenizer_2_cls, tokenizer_2_id = CLIPTokenizer, "hf-internal-testing/tiny-random-clip"
+    tokenizer_3_cls, tokenizer_3_id = AutoTokenizer, "hf-internal-testing/tiny-random-t5"
+    text_encoder_cls, text_encoder_id = CLIPTextModelWithProjection, "hf-internal-testing/tiny-sd3-text_encoder"
+    text_encoder_2_cls, text_encoder_2_id = CLIPTextModelWithProjection, "hf-internal-testing/tiny-sd3-text_encoder-2"
+    text_encoder_3_cls, text_encoder_3_id = T5EncoderModel, "hf-internal-testing/tiny-random-t5"
+
+    @property
+    def output_shape(self):
+        return (1, 32, 32, 3)
 
     @require_torch_gpu
     def test_sd3_lora(self):

tests/lora/test_lora_layers_sd3.py

@@ -22,6 +22,7 @@
 import numpy as np
 import torch
 from packaging import version
+from transformers import CLIPTextModel, CLIPTextModelWithProjection, CLIPTokenizer
 
 from diffusers import (
     ControlNetModel,
@@ -89,6 +90,14 @@ class StableDiffusionXLLoRATests(PeftLoraLoaderMixinTests, unittest.TestCase):
         "latent_channels": 4,
         "sample_size": 128,
     }
+    text_encoder_cls, text_encoder_id = CLIPTextModel, "peft-internal-testing/tiny-clip-text-2"
+    tokenizer_cls, tokenizer_id = CLIPTokenizer, "peft-internal-testing/tiny-clip-text-2"
+    text_encoder_2_cls, text_encoder_2_id = CLIPTextModelWithProjection, "peft-internal-testing/tiny-clip-text-2"
+    tokenizer_2_cls, tokenizer_2_id = CLIPTokenizer, "peft-internal-testing/tiny-clip-text-2"
+
+    @property
+    def output_shape(self):
+        return (1, 64, 64, 3)
 
     def setUp(self):
         super().setUp()