[ci] Use UTF-8 reads in FA4 policy test

fastvideo/tests/contract/test_modal_fa4_policy.py

@@ -0,0 +1,58 @@
+# SPDX-License-Identifier: Apache-2.0
+"""Guard the Modal FA4 defaults that keep CI lanes on their intended backend.
+
+Pure text/AST analysis: no fastvideo imports, no torch, no Modal client.
+"""
+
+from __future__ import annotations
+
+import ast
+from pathlib import Path
+
+REPO_ROOT = Path(__file__).resolve().parents[3]
+MODAL_ROOT = REPO_ROOT / "fastvideo" / "tests" / "modal"
+PR_TEST = MODAL_ROOT / "pr_test.py"
+LAUNCH_L40S_JOB = MODAL_ROOT / "launch_l40s_job.py"
+SSIM_TEST = MODAL_ROOT / "ssim_test.py"
+
+
+def _function_strings(path: Path, function_name: str) -> str:
+    source = path.read_text(encoding="utf-8")
+    tree = ast.parse(source)
+    for node in tree.body:
+        if isinstance(node, ast.FunctionDef) and node.name == function_name:
+            return "\n".join(
+                child.value
+                for child in ast.walk(node)
+                if isinstance(child, ast.Constant)
+                and isinstance(child.value, str)
+            )
+    raise AssertionError(f"{function_name} not found in {path}")
+
+
+def test_generic_l40s_launcher_defaults_fa4_off():
+    source = LAUNCH_L40S_JOB.read_text(encoding="utf-8")
+    assert '"FASTVIDEO_FA4": os.environ.get("FASTVIDEO_FA4", "0")' in source
+
+
+def test_ssim_launcher_keeps_fa4_enabled_by_default():
+    source = SSIM_TEST.read_text(encoding="utf-8")
+    assert '"FASTVIDEO_FA4": os.environ.get("FASTVIDEO_FA4", "1")' in source
+
+
+def test_pr_model_load_and_training_lanes_disable_fa4():
+    lanes = {
+        "run_transformer_tests": "pytest ./fastvideo/tests/transformers -vs",
+        "run_training_tests": "pytest ./fastvideo/tests/training/Vanilla -srP",
+        "run_training_lora_tests": "pytest ./fastvideo/tests/training/lora/test_lora_training.py -srP",
+        "run_training_tests_VSA": "pytest ./fastvideo/tests/training/VSA -srP",
+        "run_distill_dmd_tests": "pytest ./fastvideo/tests/training/distill/test_distill_dmd.py -vs",
+        "run_self_forcing_tests": "pytest ./fastvideo/tests/training/self-forcing/test_self_forcing.py -vs",
+        "run_train_framework_tests": "pytest ./fastvideo/tests/train/models ./fastvideo/tests/train/methods -vs",
+        "seed_grad_norm_references": "pytest ./fastvideo/tests/train/methods -vs -rs",
+    }
+
+    for function_name, pytest_command in lanes.items():
+        function_strings = _function_strings(PR_TEST, function_name)
+        assert "FASTVIDEO_FA4=0" in function_strings
+        assert pytest_command in function_strings

fastvideo/tests/modal/launch_l40s_job.py

@@ -97,9 +97,10 @@ image = (
         "TOKENIZERS_PARALLELISM": "false",
         **({"UV_TORCH_BACKEND": uv_torch_backend_override} if uv_torch_backend_override else {}),
         "FASTVIDEO_ATTENTION_BACKEND": os.environ.get("FASTVIDEO_ATTENTION_BACKEND", "FLASH_ATTN"),
-        # FA4 is opt-in (FASTVIDEO_FA4); keep CI parity with the seeded
-        # references. Caller override wins.
-        "FASTVIDEO_FA4": os.environ.get("FASTVIDEO_FA4", "1"),
+        # FA4 is opt-in (FASTVIDEO_FA4). Generic ad hoc jobs should follow the
+        # product default unless a caller opts in through the local env or
+        # --env-vars.
+        "FASTVIDEO_FA4": os.environ.get("FASTVIDEO_FA4", "0"),
     })
 )
 

fastvideo/tests/modal/pr_test.py

@@ -73,8 +73,10 @@ ci_env_secret = modal.Secret.from_dict({
     **({
         "UV_TORCH_BACKEND": uv_torch_backend_override
     } if uv_torch_backend_override else {}),
-    # FA4 is opt-in (FASTVIDEO_FA4); CI lanes keep it enabled to match the
-    # SSIM/perf baselines. Caller override wins.
+    # FA4 is opt-in (FASTVIDEO_FA4). Keep the default enabled for
+    # inference/perf parity; model-load and training lanes that do not exercise
+    # FA4 explicitly set FASTVIDEO_FA4=0 in their command strings below.
+    # Caller override wins.
     "FASTVIDEO_FA4": os.environ.get("FASTVIDEO_FA4", "1"),
 })
 
@@ -184,7 +186,8 @@ def run_vae_tests():
               volumes={"/root/data": model_vol})
 def run_transformer_tests():
     run_test(
-        "export HF_HOME='/root/data/.cache' && hf auth login --token $HF_API_KEY && pytest ./fastvideo/tests/transformers -vs"
+        "export HF_HOME='/root/data/.cache' && hf auth login --token $HF_API_KEY && "
+        "FASTVIDEO_FA4=0 pytest ./fastvideo/tests/transformers -vs"
     )
 
 
@@ -197,7 +200,8 @@ def run_transformer_tests():
               volumes={"/root/data": model_vol})
 def run_training_tests():
     run_test(
-        "export HF_HOME='/root/data/.cache' && wandb login $WANDB_API_KEY && pytest ./fastvideo/tests/training/Vanilla -srP"
+        "export HF_HOME='/root/data/.cache' && wandb login $WANDB_API_KEY && "
+        "FASTVIDEO_FA4=0 pytest ./fastvideo/tests/training/Vanilla -srP"
     )
 
 
@@ -210,7 +214,8 @@ def run_training_tests():
               volumes={"/root/data": model_vol})
 def run_training_lora_tests():
     run_test(
-        "export HF_HOME='/root/data/.cache' && wandb login $WANDB_API_KEY && pytest ./fastvideo/tests/training/lora/test_lora_training.py -srP"
+        "export HF_HOME='/root/data/.cache' && wandb login $WANDB_API_KEY && "
+        "FASTVIDEO_FA4=0 pytest ./fastvideo/tests/training/lora/test_lora_training.py -srP"
     )
 
 
@@ -220,7 +225,7 @@ def run_training_lora_tests():
               secrets=[wandb_secret, ci_env_secret])
 def run_training_tests_VSA():
     run_test(
-        "wandb login $WANDB_API_KEY && pytest ./fastvideo/tests/training/VSA -srP"
+        "wandb login $WANDB_API_KEY && FASTVIDEO_FA4=0 pytest ./fastvideo/tests/training/VSA -srP"
     )
 
 
@@ -254,7 +259,7 @@ def run_inference_lora_tests():
 @app.function(gpu="L40S:2", image=image, timeout=900, secrets=[ci_env_secret])
 def run_distill_dmd_tests():
     run_test(
-        "pytest ./fastvideo/tests/training/distill/test_distill_dmd.py -vs")
+        "FASTVIDEO_FA4=0 pytest ./fastvideo/tests/training/distill/test_distill_dmd.py -vs")
 
 
 @app.function(gpu="L40S:2",
@@ -263,7 +268,8 @@ def run_distill_dmd_tests():
               secrets=[wandb_secret, ci_env_secret])
 def run_self_forcing_tests():
     run_test(
-        "wandb login $WANDB_API_KEY && pytest ./fastvideo/tests/training/self-forcing/test_self_forcing.py -vs"
+        "wandb login $WANDB_API_KEY && "
+        "FASTVIDEO_FA4=0 pytest ./fastvideo/tests/training/self-forcing/test_self_forcing.py -vs"
     )
 
 
@@ -323,7 +329,8 @@ def run_dreamverse_app_tests():
               volumes={"/root/data": model_vol})
 def run_train_framework_tests():
     run_test(
-        "export HF_HOME='/root/data/.cache' && hf auth login --token $HF_API_KEY && pytest ./fastvideo/tests/train/models ./fastvideo/tests/train/methods -vs"
+        "export HF_HOME='/root/data/.cache' && hf auth login --token $HF_API_KEY && "
+        "FASTVIDEO_FA4=0 pytest ./fastvideo/tests/train/models ./fastvideo/tests/train/methods -vs"
     )
 
 
@@ -349,7 +356,8 @@ def seed_grad_norm_references():
     the local command and the ``_DEVICE_MAPPINGS`` table.
     """
     run_test(
-        "export HF_HOME='/root/data/.cache' && hf auth login --token $HF_API_KEY && FASTVIDEO_GRADNORM_UPDATE=1 pytest ./fastvideo/tests/train/methods -vs -rs"
+        "export HF_HOME='/root/data/.cache' && hf auth login --token $HF_API_KEY && "
+        "FASTVIDEO_FA4=0 FASTVIDEO_GRADNORM_UPDATE=1 pytest ./fastvideo/tests/train/methods -vs -rs"
     )