fix(diffusers): drop compel from requirements to unblock pip resolver

backend/python/diffusers/backend.py

@@ -40,7 +40,19 @@
 from diffusers import FluxPipeline, FluxTransformer2DModel, AutoencoderKLWan
 from diffusers.pipelines.stable_diffusion import safety_checker
 from diffusers.utils import load_image, export_to_video
-from compel import Compel, ReturnedEmbeddingsType
+# TODO: re-enable compel as a hard dependency once it supports transformers >= 5.
+# Tracking upstream: https://github.com/damian0815/compel/pull/129
+# and https://github.com/damian0815/compel/issues/128
+# Until then compel pins transformers ~= 4.25, which forces the pip resolver into
+# multi-hour backtracking storms in CI when DEPS_REFRESH rotates the cache.
+# Keep the import optional and gate usage on the COMPEL env var (set COMPEL=1 to opt in).
+try:
+    from compel import Compel, ReturnedEmbeddingsType
+    COMPEL_AVAILABLE = True
+except ImportError:
+    Compel = None
+    ReturnedEmbeddingsType = None
+    COMPEL_AVAILABLE = False
 from optimum.quanto import freeze, qfloat8, quantize
 from transformers import T5EncoderModel
 from safetensors.torch import load_file
@@ -66,6 +78,9 @@
 
 _ONE_DAY_IN_SECONDS = 60 * 60 * 24
 COMPEL = os.environ.get("COMPEL", "0") == "1"
+if COMPEL and not COMPEL_AVAILABLE:
+    print("WARNING: COMPEL is enabled but the compel module is not installed. Install it manually (`pip install compel`) or unset COMPEL. Falling back to standard prompt processing.", file=sys.stderr)
+    COMPEL = False
 SD_EMBED = os.environ.get("SD_EMBED", "0") == "1"
 # Warn if SD_EMBED is enabled but the module is not available
 if SD_EMBED and not SD_EMBED_AVAILABLE:

backend/python/diffusers/requirements-cpu.txt

@@ -4,10 +4,15 @@ opencv-python
 transformers
 torchvision==0.22.1
 accelerate
-compel
 git+https://github.com/xhinker/sd_embed
 peft
 sentencepiece
 torch==2.7.1
 optimum-quanto
-ftfy
+ftfy
+# TODO: re-add compel once it supports transformers >= 5.
+# Tracking: https://github.com/damian0815/compel/pull/129
+#           https://github.com/damian0815/compel/issues/128
+# compel currently pins transformers~=4.25, which forced pip into multi-hour
+# resolver backtracking storms in CI. backend.py imports it lazily and gates
+# the COMPEL=1 env var on the import succeeding, so dropping it here is safe.

backend/python/diffusers/requirements-cublas12.txt

@@ -4,10 +4,15 @@ opencv-python
 transformers
 torchvision
 accelerate
-compel
 git+https://github.com/xhinker/sd_embed
 peft
 sentencepiece
 torch
 ftfy
 optimum-quanto
+# TODO: re-add compel once it supports transformers >= 5.
+# Tracking: https://github.com/damian0815/compel/pull/129
+#           https://github.com/damian0815/compel/issues/128
+# compel currently pins transformers~=4.25, which forced pip into multi-hour
+# resolver backtracking storms in CI. backend.py imports it lazily and gates
+# the COMPEL=1 env var on the import succeeding, so dropping it here is safe.

backend/python/diffusers/requirements-cublas13.txt

@@ -4,10 +4,15 @@ opencv-python
 transformers
 torchvision
 accelerate
-compel
 git+https://github.com/xhinker/sd_embed
 peft
 sentencepiece
 torch
 ftfy
 optimum-quanto
+# TODO: re-add compel once it supports transformers >= 5.
+# Tracking: https://github.com/damian0815/compel/pull/129
+#           https://github.com/damian0815/compel/issues/128
+# compel currently pins transformers~=4.25, which forced pip into multi-hour
+# resolver backtracking storms in CI. backend.py imports it lazily and gates
+# the COMPEL=1 env var on the import succeeding, so dropping it here is safe.

backend/python/diffusers/requirements-hipblas.txt

@@ -5,8 +5,13 @@ git+https://github.com/huggingface/diffusers
 opencv-python
 transformers
 accelerate
-compel
 peft
 sentencepiece
 optimum-quanto
-ftfy
+ftfy
+# TODO: re-add compel once it supports transformers >= 5.
+# Tracking: https://github.com/damian0815/compel/pull/129
+#           https://github.com/damian0815/compel/issues/128
+# compel currently pins transformers~=4.25, which forced pip into multi-hour
+# resolver backtracking storms in CI. backend.py imports it lazily and gates
+# the COMPEL=1 env var on the import succeeding, so dropping it here is safe.

backend/python/diffusers/requirements-intel.txt

@@ -7,9 +7,14 @@ git+https://github.com/huggingface/diffusers
 opencv-python
 transformers
 accelerate
-compel
 git+https://github.com/xhinker/sd_embed
 peft
 sentencepiece
 optimum-quanto
-ftfy
+ftfy
+# TODO: re-add compel once it supports transformers >= 5.
+# Tracking: https://github.com/damian0815/compel/pull/129
+#           https://github.com/damian0815/compel/issues/128
+# compel currently pins transformers~=4.25, which forced pip into multi-hour
+# resolver backtracking storms in CI. backend.py imports it lazily and gates
+# the COMPEL=1 env var on the import succeeding, so dropping it here is safe.

backend/python/diffusers/requirements-l4t12.txt

@@ -3,10 +3,15 @@ torch
 git+https://github.com/huggingface/diffusers
 transformers
 accelerate
-compel
 peft
 optimum-quanto
 numpy<2
 sentencepiece
 torchvision
 ftfy
+# TODO: re-add compel once it supports transformers >= 5.
+# Tracking: https://github.com/damian0815/compel/pull/129
+#           https://github.com/damian0815/compel/issues/128
+# compel currently pins transformers~=4.25, which forced pip into multi-hour
+# resolver backtracking storms in CI. backend.py imports it lazily and gates
+# the COMPEL=1 env var on the import succeeding, so dropping it here is safe.

backend/python/diffusers/requirements-l4t13.txt

@@ -3,11 +3,16 @@ torch
 git+https://github.com/huggingface/diffusers
 transformers
 accelerate
-compel
 peft
 optimum-quanto
 numpy<2
 sentencepiece
 torchvision
 ftfy
 chardet
+# TODO: re-add compel once it supports transformers >= 5.
+# Tracking: https://github.com/damian0815/compel/pull/129
+#           https://github.com/damian0815/compel/issues/128
+# compel currently pins transformers~=4.25, which forced pip into multi-hour
+# resolver backtracking storms in CI. backend.py imports it lazily and gates
+# the COMPEL=1 env var on the import succeeding, so dropping it here is safe.

backend/python/diffusers/requirements-mps.txt

@@ -4,8 +4,13 @@ git+https://github.com/huggingface/diffusers
 opencv-python
 transformers
 accelerate
-compel
 peft
 sentencepiece
 optimum-quanto
-ftfy
+ftfy
+# TODO: re-add compel once it supports transformers >= 5.
+# Tracking: https://github.com/damian0815/compel/pull/129
+#           https://github.com/damian0815/compel/issues/128
+# compel currently pins transformers~=4.25, which forced pip into multi-hour
+# resolver backtracking storms in CI. backend.py imports it lazily and gates
+# the COMPEL=1 env var on the import succeeding, so dropping it here is safe.