Revert "another fix."

This reverts commit ab07b603ab.

docs/source/en/optimization/attention_backends.md

@@ -143,7 +143,6 @@ Refer to the table below for a complete list of available attention backends and
 | `flash_varlen` | [FlashAttention](https://github.com/Dao-AILab/flash-attention) | Variable length FlashAttention |
 | `flash_varlen_hub` | [FlashAttention](https://github.com/Dao-AILab/flash-attention) | Variable length FlashAttention from kernels |
 | `aiter` | [AI Tensor Engine for ROCm](https://github.com/ROCm/aiter) | FlashAttention for AMD ROCm |
-| `flash_4_hub` | [FlashAttention](https://github.com/Dao-AILab/flash-attention) | FlashAttention-4 |
 | `_flash_3` | [FlashAttention](https://github.com/Dao-AILab/flash-attention) | FlashAttention-3 |
 | `_flash_varlen_3` | [FlashAttention](https://github.com/Dao-AILab/flash-attention) | Variable length FlashAttention-3 |
 | `_flash_3_hub` | [FlashAttention](https://github.com/Dao-AILab/flash-attention) | FlashAttention-3 from kernels |

src/diffusers/models/attention_dispatch.py

@@ -229,7 +229,6 @@ class AttentionBackendName(str, Enum):
     FLASH_HUB = "flash_hub"
     FLASH_VARLEN = "flash_varlen"
     FLASH_VARLEN_HUB = "flash_varlen_hub"
-    FLASH_4_HUB = "flash_4_hub"
     _FLASH_3 = "_flash_3"
     _FLASH_VARLEN_3 = "_flash_varlen_3"
     _FLASH_3_HUB = "_flash_3_hub"
@@ -359,11 +358,6 @@ _HUB_KERNELS_REGISTRY: dict["AttentionBackendName", _HubKernelConfig] = {
         function_attr="sageattn",
         version=1,
     ),
-    AttentionBackendName.FLASH_4_HUB: _HubKernelConfig(
-        repo_id="kernels-staging/flash-attn4",
-        function_attr="flash_attn_func",
-        version=0,
-    ),
 }
 
 
@@ -527,7 +521,6 @@ def _check_attention_backend_requirements(backend: AttentionBackendName) -> None
         AttentionBackendName._FLASH_3_HUB,
         AttentionBackendName._FLASH_3_VARLEN_HUB,
         AttentionBackendName.SAGE_HUB,
-        AttentionBackendName.FLASH_4_HUB,
     ]:
         if not is_kernels_available():
             raise RuntimeError(
@@ -538,11 +531,6 @@ def _check_attention_backend_requirements(backend: AttentionBackendName) -> None
                 f"Backend '{backend.value}' needs to be used with a `kernels` version of at least 0.12. Please update with `pip install -U kernels`."
             )
 
-        if backend == AttentionBackendName.FLASH_4_HUB and not is_kernels_available(">=", "0.12.3"):
-            raise RuntimeError(
-                f"Backend '{backend.value}' needs to be used with a `kernels` version of at least 0.12.3. Please update with `pip install -U kernels`."
-            )
-
     elif backend == AttentionBackendName.AITER:
         if not _CAN_USE_AITER_ATTN:
             raise RuntimeError(
@@ -2688,37 +2676,6 @@ def _flash_attention_3_varlen_hub(
     return (out, lse) if return_lse else out
 
 
-@_AttentionBackendRegistry.register(
-    AttentionBackendName.FLASH_4_HUB,
-    constraints=[_check_device, _check_qkv_dtype_bf16_or_fp16, _check_shape],
-    supports_context_parallel=False,
-)
-def _flash_attention_4_hub(
-    query: torch.Tensor,
-    key: torch.Tensor,
-    value: torch.Tensor,
-    attn_mask: torch.Tensor | None = None,
-    scale: float | None = None,
-    is_causal: bool = False,
-    return_lse: bool = False,
-    _parallel_config: "ParallelConfig" | None = None,
-) -> torch.Tensor:
-    if attn_mask is not None:
-        raise ValueError("`attn_mask` is not supported for flash-attn 4.")
-
-    func = _HUB_KERNELS_REGISTRY[AttentionBackendName.FLASH_4_HUB].kernel_fn
-    out = func(
-        q=query,
-        k=key,
-        v=value,
-        softmax_scale=scale,
-        causal=is_causal,
-    )
-    if isinstance(out, tuple):
-        return (out[0], out[1]) if return_lse else out[0]
-    return out
-
-
 @_AttentionBackendRegistry.register(
     AttentionBackendName._FLASH_VARLEN_3,
     constraints=[_check_device, _check_qkv_dtype_bf16_or_fp16, _check_shape],

src/diffusers/pipelines/audioldm2/pipeline_audioldm2.py

@@ -324,18 +324,17 @@ class AudioLDM2Pipeline(DiffusionPipeline):
             `inputs_embeds (`torch.Tensor` of shape `(batch_size, sequence_length, hidden_size)`):
                 The sequence of generated hidden-states.
         """
+        cache_position_kwargs = {}
+        if is_transformers_version("<", "4.52.1"):
+            cache_position_kwargs["input_ids"] = inputs_embeds
+        else:
+            cache_position_kwargs["seq_length"] = inputs_embeds.shape[0]
+            cache_position_kwargs["device"] = (
+                self.language_model.device if getattr(self, "language_model", None) is not None else self.device
+            )
+        cache_position_kwargs["model_kwargs"] = model_kwargs
         max_new_tokens = max_new_tokens if max_new_tokens is not None else self.language_model.config.max_new_tokens
-        if hasattr(self.language_model, "_get_initial_cache_position"):
-            cache_position_kwargs = {}
-            if is_transformers_version("<", "4.52.1"):
-                cache_position_kwargs["input_ids"] = inputs_embeds
-            else:
-                cache_position_kwargs["seq_length"] = inputs_embeds.shape[0]
-                cache_position_kwargs["device"] = (
-                    self.language_model.device if getattr(self, "language_model", None) is not None else self.device
-                )
-            cache_position_kwargs["model_kwargs"] = model_kwargs
-            model_kwargs = self.language_model._get_initial_cache_position(**cache_position_kwargs)
+        model_kwargs = self.language_model._get_initial_cache_position(**cache_position_kwargs)
 
         for _ in range(max_new_tokens):
             # prepare model inputs

src/diffusers/utils/testing_utils.py

@@ -29,7 +29,6 @@ from numpy.linalg import norm
 from packaging import version
 
 from .constants import DIFFUSERS_REQUEST_TIMEOUT
-from .deprecation_utils import deprecate
 from .import_utils import (
     BACKENDS_MAPPING,
     is_accelerate_available,
@@ -68,11 +67,9 @@ else:
 global_rng = random.Random()
 
 logger = get_logger(__name__)
-deprecate(
-    "diffusers.utils.testing_utils",
-    "1.0.0",
-    "diffusers.utils.testing_utils is deprecated and will be removed in a future version. "
-    "Determinism and device backend utilities have been moved to `diffusers.utils.torch_utils`. ",
+logger.warning(
+    "diffusers.utils.testing_utils' is deprecated and will be removed in a future version. "
+    "Determinism and device backend utilities have been moved to `diffusers.utils.torch_utils`. "
 )
 _required_peft_version = is_peft_available() and version.parse(
     version.parse(importlib.metadata.version("peft")).base_version

tests/lora/test_lora_layers_wanvace.py

@@ -28,6 +28,7 @@ from diffusers.utils.import_utils import is_peft_available
 
 from ..testing_utils import (
     floats_tensor,
+    is_flaky,
     require_peft_backend,
     require_peft_version_greater,
     skip_mps,
@@ -45,6 +46,7 @@ from .utils import PeftLoraLoaderMixinTests  # noqa: E402
 
 @require_peft_backend
 @skip_mps
+@is_flaky(max_attempts=10, description="very flaky class")
 class WanVACELoRATests(unittest.TestCase, PeftLoraLoaderMixinTests):
     pipeline_class = WanVACEPipeline
     scheduler_cls = FlowMatchEulerDiscreteScheduler
@@ -71,8 +73,8 @@ class WanVACELoRATests(unittest.TestCase, PeftLoraLoaderMixinTests):
         "base_dim": 3,
         "z_dim": 4,
         "dim_mult": [1, 1, 1, 1],
-        "latents_mean": [-0.7571, -0.7089, -0.9113, -0.7245],
-        "latents_std": [2.8184, 1.4541, 2.3275, 2.6558],
+        "latents_mean": torch.randn(4).numpy().tolist(),
+        "latents_std": torch.randn(4).numpy().tolist(),
         "num_res_blocks": 1,
         "temperal_downsample": [False, True, True],
     }

tests/modular_pipelines/test_conditional_pipeline_blocks.py

@@ -0,0 +1,242 @@
+# Copyright 2025 The HuggingFace Team. All rights reserved.
+#
+# 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.
+
+
+from diffusers.modular_pipelines import (
+    AutoPipelineBlocks,
+    ConditionalPipelineBlocks,
+    InputParam,
+    ModularPipelineBlocks,
+)
+
+
+class TextToImageBlock(ModularPipelineBlocks):
+    model_name = "text2img"
+
+    @property
+    def inputs(self):
+        return [InputParam(name="prompt")]
+
+    @property
+    def intermediate_outputs(self):
+        return []
+
+    @property
+    def description(self):
+        return "text-to-image workflow"
+
+    def __call__(self, components, state):
+        block_state = self.get_block_state(state)
+        block_state.workflow = "text2img"
+        self.set_block_state(state, block_state)
+        return components, state
+
+
+class ImageToImageBlock(ModularPipelineBlocks):
+    model_name = "img2img"
+
+    @property
+    def inputs(self):
+        return [InputParam(name="prompt"), InputParam(name="image")]
+
+    @property
+    def intermediate_outputs(self):
+        return []
+
+    @property
+    def description(self):
+        return "image-to-image workflow"
+
+    def __call__(self, components, state):
+        block_state = self.get_block_state(state)
+        block_state.workflow = "img2img"
+        self.set_block_state(state, block_state)
+        return components, state
+
+
+class InpaintBlock(ModularPipelineBlocks):
+    model_name = "inpaint"
+
+    @property
+    def inputs(self):
+        return [InputParam(name="prompt"), InputParam(name="image"), InputParam(name="mask")]
+
+    @property
+    def intermediate_outputs(self):
+        return []
+
+    @property
+    def description(self):
+        return "inpaint workflow"
+
+    def __call__(self, components, state):
+        block_state = self.get_block_state(state)
+        block_state.workflow = "inpaint"
+        self.set_block_state(state, block_state)
+        return components, state
+
+
+class ConditionalImageBlocks(ConditionalPipelineBlocks):
+    block_classes = [InpaintBlock, ImageToImageBlock, TextToImageBlock]
+    block_names = ["inpaint", "img2img", "text2img"]
+    block_trigger_inputs = ["mask", "image"]
+    default_block_name = "text2img"
+
+    @property
+    def description(self):
+        return "Conditional image blocks for testing"
+
+    def select_block(self, mask=None, image=None) -> str | None:
+        if mask is not None:
+            return "inpaint"
+        if image is not None:
+            return "img2img"
+        return None  # falls back to default_block_name
+
+
+class OptionalConditionalBlocks(ConditionalPipelineBlocks):
+    block_classes = [InpaintBlock, ImageToImageBlock]
+    block_names = ["inpaint", "img2img"]
+    block_trigger_inputs = ["mask", "image"]
+    default_block_name = None  # no default; block can be skipped
+
+    @property
+    def description(self):
+        return "Optional conditional blocks (skippable)"
+
+    def select_block(self, mask=None, image=None) -> str | None:
+        if mask is not None:
+            return "inpaint"
+        if image is not None:
+            return "img2img"
+        return None
+
+
+class AutoImageBlocks(AutoPipelineBlocks):
+    block_classes = [InpaintBlock, ImageToImageBlock, TextToImageBlock]
+    block_names = ["inpaint", "img2img", "text2img"]
+    block_trigger_inputs = ["mask", "image", None]
+
+    @property
+    def description(self):
+        return "Auto image blocks for testing"
+
+
+class TestConditionalPipelineBlocksSelectBlock:
+    def test_select_block_with_mask(self):
+        blocks = ConditionalImageBlocks()
+        assert blocks.select_block(mask="something") == "inpaint"
+
+    def test_select_block_with_image(self):
+        blocks = ConditionalImageBlocks()
+        assert blocks.select_block(image="something") == "img2img"
+
+    def test_select_block_with_mask_and_image(self):
+        blocks = ConditionalImageBlocks()
+        assert blocks.select_block(mask="m", image="i") == "inpaint"
+
+    def test_select_block_no_triggers_returns_none(self):
+        blocks = ConditionalImageBlocks()
+        assert blocks.select_block() is None
+
+    def test_select_block_explicit_none_values(self):
+        blocks = ConditionalImageBlocks()
+        assert blocks.select_block(mask=None, image=None) is None
+
+
+class TestConditionalPipelineBlocksWorkflowSelection:
+    def test_default_workflow_when_no_triggers(self):
+        blocks = ConditionalImageBlocks()
+        execution = blocks.get_execution_blocks()
+        assert execution is not None
+        assert isinstance(execution, TextToImageBlock)
+
+    def test_mask_trigger_selects_inpaint(self):
+        blocks = ConditionalImageBlocks()
+        execution = blocks.get_execution_blocks(mask=True)
+        assert isinstance(execution, InpaintBlock)
+
+    def test_image_trigger_selects_img2img(self):
+        blocks = ConditionalImageBlocks()
+        execution = blocks.get_execution_blocks(image=True)
+        assert isinstance(execution, ImageToImageBlock)
+
+    def test_mask_and_image_selects_inpaint(self):
+        blocks = ConditionalImageBlocks()
+        execution = blocks.get_execution_blocks(mask=True, image=True)
+        assert isinstance(execution, InpaintBlock)
+
+    def test_skippable_block_returns_none(self):
+        blocks = OptionalConditionalBlocks()
+        execution = blocks.get_execution_blocks()
+        assert execution is None
+
+    def test_skippable_block_still_selects_when_triggered(self):
+        blocks = OptionalConditionalBlocks()
+        execution = blocks.get_execution_blocks(image=True)
+        assert isinstance(execution, ImageToImageBlock)
+
+
+class TestAutoPipelineBlocksSelectBlock:
+    def test_auto_select_mask(self):
+        blocks = AutoImageBlocks()
+        assert blocks.select_block(mask="m") == "inpaint"
+
+    def test_auto_select_image(self):
+        blocks = AutoImageBlocks()
+        assert blocks.select_block(image="i") == "img2img"
+
+    def test_auto_select_default(self):
+        blocks = AutoImageBlocks()
+        # No trigger -> returns None -> falls back to default (text2img)
+        assert blocks.select_block() is None
+
+    def test_auto_select_priority_order(self):
+        blocks = AutoImageBlocks()
+        assert blocks.select_block(mask="m", image="i") == "inpaint"
+
+
+class TestAutoPipelineBlocksWorkflowSelection:
+    def test_auto_default_workflow(self):
+        blocks = AutoImageBlocks()
+        execution = blocks.get_execution_blocks()
+        assert isinstance(execution, TextToImageBlock)
+
+    def test_auto_mask_workflow(self):
+        blocks = AutoImageBlocks()
+        execution = blocks.get_execution_blocks(mask=True)
+        assert isinstance(execution, InpaintBlock)
+
+    def test_auto_image_workflow(self):
+        blocks = AutoImageBlocks()
+        execution = blocks.get_execution_blocks(image=True)
+        assert isinstance(execution, ImageToImageBlock)
+
+
+class TestConditionalPipelineBlocksStructure:
+    def test_block_names_accessible(self):
+        blocks = ConditionalImageBlocks()
+        sub = dict(blocks.sub_blocks)
+        assert set(sub.keys()) == {"inpaint", "img2img", "text2img"}
+
+    def test_sub_block_types(self):
+        blocks = ConditionalImageBlocks()
+        sub = dict(blocks.sub_blocks)
+        assert isinstance(sub["inpaint"], InpaintBlock)
+        assert isinstance(sub["img2img"], ImageToImageBlock)
+        assert isinstance(sub["text2img"], TextToImageBlock)
+
+    def test_description(self):
+        blocks = ConditionalImageBlocks()
+        assert "Conditional" in blocks.description

tests/modular_pipelines/test_modular_pipelines_common.py

@@ -5,16 +5,10 @@ from typing import Callable
 
 import pytest
 import torch
-from huggingface_hub import hf_hub_download
 
 import diffusers
 from diffusers import AutoModel, ComponentsManager, ModularPipeline, ModularPipelineBlocks
 from diffusers.guiders import ClassifierFreeGuidance
-from diffusers.modular_pipelines import (
-    ConditionalPipelineBlocks,
-    LoopSequentialPipelineBlocks,
-    SequentialPipelineBlocks,
-)
 from diffusers.modular_pipelines.modular_pipeline_utils import (
     ComponentSpec,
     ConfigSpec,
@@ -25,7 +19,6 @@ from diffusers.modular_pipelines.modular_pipeline_utils import (
 from diffusers.utils import logging
 
 from ..testing_utils import (
-    CaptureLogger,
     backend_empty_cache,
     numpy_cosine_similarity_distance,
     require_accelerator,
@@ -33,33 +26,6 @@ from ..testing_utils import (
 )
 
 
-def _get_specified_components(path_or_repo_id, cache_dir=None):
-    if os.path.isdir(path_or_repo_id):
-        config_path = os.path.join(path_or_repo_id, "modular_model_index.json")
-    else:
-        try:
-            config_path = hf_hub_download(
-                repo_id=path_or_repo_id,
-                filename="modular_model_index.json",
-                local_dir=cache_dir,
-            )
-        except Exception:
-            return None
-
-    with open(config_path) as f:
-        config = json.load(f)
-
-    components = set()
-    for k, v in config.items():
-        if isinstance(v, (str, int, float, bool)):
-            continue
-        for entry in v:
-            if isinstance(entry, dict) and (entry.get("repo") or entry.get("pretrained_model_name_or_path")):
-                components.add(k)
-                break
-    return components
-
-
 class ModularPipelineTesterMixin:
     """
     It provides a set of common tests for each modular pipeline,
@@ -388,39 +354,6 @@ class ModularPipelineTesterMixin:
 
         assert torch.abs(image_slices[0] - image_slices[1]).max() < 1e-3
 
-    def test_load_expected_components_from_pretrained(self, tmp_path):
-        pipe = self.get_pipeline()
-        expected = _get_specified_components(self.pretrained_model_name_or_path, cache_dir=tmp_path)
-        if not expected:
-            pytest.skip("Skipping test as we couldn't fetch the expected components.")
-
-        actual = {
-            name
-            for name in pipe.components
-            if getattr(pipe, name, None) is not None
-            and getattr(getattr(pipe, name), "_diffusers_load_id", None) not in (None, "null")
-        }
-        assert expected == actual, f"Component mismatch: missing={expected - actual}, unexpected={actual - expected}"
-
-    def test_load_expected_components_from_save_pretrained(self, tmp_path):
-        pipe = self.get_pipeline()
-        save_dir = str(tmp_path / "saved-pipeline")
-        pipe.save_pretrained(save_dir)
-
-        expected = _get_specified_components(save_dir)
-        loaded_pipe = ModularPipeline.from_pretrained(save_dir)
-        loaded_pipe.load_components(torch_dtype=torch.float32)
-
-        actual = {
-            name
-            for name in loaded_pipe.components
-            if getattr(loaded_pipe, name, None) is not None
-            and getattr(getattr(loaded_pipe, name), "_diffusers_load_id", None) not in (None, "null")
-        }
-        assert expected == actual, (
-            f"Component mismatch after save/load: missing={expected - actual}, unexpected={actual - expected}"
-        )
-
     def test_modular_index_consistency(self, tmp_path):
         pipe = self.get_pipeline()
         components_spec = pipe._component_specs
@@ -498,117 +431,6 @@ class ModularGuiderTesterMixin:
         assert max_diff > expected_max_diff, "Output with CFG must be different from normal inference"
 
 
-class TestCustomBlockRequirements:
-    def get_dummy_block_pipe(self):
-        class DummyBlockOne:
-            # keep two arbitrary deps so that we can test warnings.
-            _requirements = {"xyz": ">=0.8.0", "abc": ">=10.0.0"}
-
-        class DummyBlockTwo:
-            # keep two dependencies that will be available during testing.
-            _requirements = {"transformers": ">=4.44.0", "diffusers": ">=0.2.0"}
-
-        pipe = SequentialPipelineBlocks.from_blocks_dict(
-            {"dummy_block_one": DummyBlockOne, "dummy_block_two": DummyBlockTwo}
-        )
-        return pipe
-
-    def get_dummy_conditional_block_pipe(self):
-        class DummyBlockOne:
-            _requirements = {"xyz": ">=0.8.0", "abc": ">=10.0.0"}
-
-        class DummyBlockTwo:
-            _requirements = {"transformers": ">=4.44.0", "diffusers": ">=0.2.0"}
-
-        class DummyConditionalBlocks(ConditionalPipelineBlocks):
-            block_classes = [DummyBlockOne, DummyBlockTwo]
-            block_names = ["block_one", "block_two"]
-            block_trigger_inputs = []
-
-            def select_block(self, **kwargs):
-                return "block_one"
-
-        return DummyConditionalBlocks()
-
-    def get_dummy_loop_block_pipe(self):
-        class DummyBlockOne:
-            _requirements = {"xyz": ">=0.8.0", "abc": ">=10.0.0"}
-
-        class DummyBlockTwo:
-            _requirements = {"transformers": ">=4.44.0", "diffusers": ">=0.2.0"}
-
-        return LoopSequentialPipelineBlocks.from_blocks_dict({"block_one": DummyBlockOne, "block_two": DummyBlockTwo})
-
-    def test_sequential_block_requirements_save_load(self, tmp_path):
-        pipe = self.get_dummy_block_pipe()
-        pipe.save_pretrained(str(tmp_path))
-
-        config_path = tmp_path / "modular_config.json"
-
-        with open(config_path, "r") as f:
-            config = json.load(f)
-
-        assert "requirements" in config
-        requirements = config["requirements"]
-
-        expected_requirements = {
-            "xyz": ">=0.8.0",
-            "abc": ">=10.0.0",
-            "transformers": ">=4.44.0",
-            "diffusers": ">=0.2.0",
-        }
-        assert expected_requirements == requirements
-
-    def test_sequential_block_requirements_warnings(self, tmp_path):
-        pipe = self.get_dummy_block_pipe()
-
-        logger = logging.get_logger("diffusers.modular_pipelines.modular_pipeline_utils")
-        logger.setLevel(30)
-
-        with CaptureLogger(logger) as cap_logger:
-            pipe.save_pretrained(str(tmp_path))
-
-        template = "{req} was specified in the requirements but wasn't found in the current environment"
-        msg_xyz = template.format(req="xyz")
-        msg_abc = template.format(req="abc")
-        assert msg_xyz in str(cap_logger.out)
-        assert msg_abc in str(cap_logger.out)
-
-    def test_conditional_block_requirements_save_load(self, tmp_path):
-        pipe = self.get_dummy_conditional_block_pipe()
-        pipe.save_pretrained(str(tmp_path))
-
-        config_path = tmp_path / "modular_config.json"
-        with open(config_path, "r") as f:
-            config = json.load(f)
-
-        assert "requirements" in config
-        expected_requirements = {
-            "xyz": ">=0.8.0",
-            "abc": ">=10.0.0",
-            "transformers": ">=4.44.0",
-            "diffusers": ">=0.2.0",
-        }
-        assert expected_requirements == config["requirements"]
-
-    def test_loop_block_requirements_save_load(self, tmp_path):
-        pipe = self.get_dummy_loop_block_pipe()
-        pipe.save_pretrained(str(tmp_path))
-
-        config_path = tmp_path / "modular_config.json"
-        with open(config_path, "r") as f:
-            config = json.load(f)
-
-        assert "requirements" in config
-        expected_requirements = {
-            "xyz": ">=0.8.0",
-            "abc": ">=10.0.0",
-            "transformers": ">=4.44.0",
-            "diffusers": ">=0.2.0",
-        }
-        assert expected_requirements == config["requirements"]
-
-
 class TestModularModelCardContent:
     def create_mock_block(self, name="TestBlock", description="Test block description"):
         class MockBlock:

tests/modular_pipelines/test_modular_pipelines_custom_blocks.py

@@ -24,14 +24,18 @@ import torch
 from diffusers import FluxTransformer2DModel
 from diffusers.modular_pipelines import (
     ComponentSpec,
+    ConditionalPipelineBlocks,
     InputParam,
+    LoopSequentialPipelineBlocks,
     ModularPipelineBlocks,
     OutputParam,
     PipelineState,
+    SequentialPipelineBlocks,
     WanModularPipeline,
 )
+from diffusers.utils import logging
 
-from ..testing_utils import nightly, require_torch, require_torch_accelerator, slow, torch_device
+from ..testing_utils import CaptureLogger, nightly, require_torch, require_torch_accelerator, slow, torch_device
 
 
 def _create_tiny_model_dir(model_dir):
@@ -463,6 +467,117 @@ class TestModularCustomBlocks:
         assert output_prompt.startswith("Modular diffusers + ")
 
 
+class TestCustomBlockRequirements:
+    def get_dummy_block_pipe(self):
+        class DummyBlockOne:
+            # keep two arbitrary deps so that we can test warnings.
+            _requirements = {"xyz": ">=0.8.0", "abc": ">=10.0.0"}
+
+        class DummyBlockTwo:
+            # keep two dependencies that will be available during testing.
+            _requirements = {"transformers": ">=4.44.0", "diffusers": ">=0.2.0"}
+
+        pipe = SequentialPipelineBlocks.from_blocks_dict(
+            {"dummy_block_one": DummyBlockOne, "dummy_block_two": DummyBlockTwo}
+        )
+        return pipe
+
+    def get_dummy_conditional_block_pipe(self):
+        class DummyBlockOne:
+            _requirements = {"xyz": ">=0.8.0", "abc": ">=10.0.0"}
+
+        class DummyBlockTwo:
+            _requirements = {"transformers": ">=4.44.0", "diffusers": ">=0.2.0"}
+
+        class DummyConditionalBlocks(ConditionalPipelineBlocks):
+            block_classes = [DummyBlockOne, DummyBlockTwo]
+            block_names = ["block_one", "block_two"]
+            block_trigger_inputs = []
+
+            def select_block(self, **kwargs):
+                return "block_one"
+
+        return DummyConditionalBlocks()
+
+    def get_dummy_loop_block_pipe(self):
+        class DummyBlockOne:
+            _requirements = {"xyz": ">=0.8.0", "abc": ">=10.0.0"}
+
+        class DummyBlockTwo:
+            _requirements = {"transformers": ">=4.44.0", "diffusers": ">=0.2.0"}
+
+        return LoopSequentialPipelineBlocks.from_blocks_dict({"block_one": DummyBlockOne, "block_two": DummyBlockTwo})
+
+    def test_sequential_block_requirements_save_load(self, tmp_path):
+        pipe = self.get_dummy_block_pipe()
+        pipe.save_pretrained(str(tmp_path))
+
+        config_path = tmp_path / "modular_config.json"
+
+        with open(config_path, "r") as f:
+            config = json.load(f)
+
+        assert "requirements" in config
+        requirements = config["requirements"]
+
+        expected_requirements = {
+            "xyz": ">=0.8.0",
+            "abc": ">=10.0.0",
+            "transformers": ">=4.44.0",
+            "diffusers": ">=0.2.0",
+        }
+        assert expected_requirements == requirements
+
+    def test_sequential_block_requirements_warnings(self, tmp_path):
+        pipe = self.get_dummy_block_pipe()
+
+        logger = logging.get_logger("diffusers.modular_pipelines.modular_pipeline_utils")
+        logger.setLevel(30)
+
+        with CaptureLogger(logger) as cap_logger:
+            pipe.save_pretrained(str(tmp_path))
+
+        template = "{req} was specified in the requirements but wasn't found in the current environment"
+        msg_xyz = template.format(req="xyz")
+        msg_abc = template.format(req="abc")
+        assert msg_xyz in str(cap_logger.out)
+        assert msg_abc in str(cap_logger.out)
+
+    def test_conditional_block_requirements_save_load(self, tmp_path):
+        pipe = self.get_dummy_conditional_block_pipe()
+        pipe.save_pretrained(str(tmp_path))
+
+        config_path = tmp_path / "modular_config.json"
+        with open(config_path, "r") as f:
+            config = json.load(f)
+
+        assert "requirements" in config
+        expected_requirements = {
+            "xyz": ">=0.8.0",
+            "abc": ">=10.0.0",
+            "transformers": ">=4.44.0",
+            "diffusers": ">=0.2.0",
+        }
+        assert expected_requirements == config["requirements"]
+
+    def test_loop_block_requirements_save_load(self, tmp_path):
+        pipe = self.get_dummy_loop_block_pipe()
+        pipe.save_pretrained(str(tmp_path))
+
+        config_path = tmp_path / "modular_config.json"
+        with open(config_path, "r") as f:
+            config = json.load(f)
+
+        assert "requirements" in config
+        expected_requirements = {
+            "xyz": ">=0.8.0",
+            "abc": ">=10.0.0",
+            "transformers": ">=4.44.0",
+            "diffusers": ">=0.2.0",
+        }
+        assert expected_requirements == config["requirements"]
+
+
 @slow
 @nightly
 @require_torch

tests/others/test_utils.py

@@ -13,10 +13,8 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-import importlib
 import os
 import unittest
-import warnings
 
 import pytest
 
@@ -184,25 +182,6 @@ class DeprecateTester(unittest.TestCase):
         assert str(warning.warning) == "This message is better!!!"
         assert "diffusers/tests/others/test_utils.py" in warning.filename
 
-    def test_deprecate_testing_utils_module(self):
-        import diffusers.utils.testing_utils
-
-        with warnings.catch_warnings(record=True) as caught_warnings:
-            warnings.simplefilter("always")
-            importlib.reload(diffusers.utils.testing_utils)
-
-        deprecation_warnings = [w for w in caught_warnings if issubclass(w.category, FutureWarning)]
-        assert len(deprecation_warnings) >= 1, "Expected at least one FutureWarning from diffusers.utils.testing_utils"
-
-        messages = [str(w.message) for w in deprecation_warnings]
-        assert any("diffusers.utils.testing_utils" in msg for msg in messages), (
-            f"Expected a deprecation warning mentioning 'diffusers.utils.testing_utils', got: {messages}"
-        )
-        assert any(
-            "diffusers.utils.testing_utils is deprecated and will be removed in a future version." in msg
-            for msg in messages
-        ), f"Expected deprecation message substring not found, got: {messages}"
-
 
 # Copied from https://github.com/huggingface/transformers/blob/main/tests/utils/test_expectations.py
 class ExpectationsTester(unittest.TestCase):