fix(image): patch realesrgan torchvision compatibility (#4110)

src/optional_deps.py

@@ -0,0 +1,32 @@
+"""Compatibility helpers for optional third-party dependencies."""
+
+from __future__ import annotations
+
+import sys
+import types
+
+
+def patch_realesrgan_torchvision_compat() -> None:
+    """Restore the torchvision import path expected by BasicSR/Real-ESRGAN."""
+    module_name = "torchvision.transforms.functional_tensor"
+    if module_name in sys.modules:
+        return
+    try:
+        from torchvision.transforms import functional
+    except Exception:
+        return
+
+    rgb_to_grayscale = getattr(functional, "rgb_to_grayscale", None)
+    if rgb_to_grayscale is None:
+        return
+
+    shim = types.ModuleType(module_name)
+    shim.rgb_to_grayscale = rgb_to_grayscale
+    shim.__getattr__ = lambda name: getattr(functional, name)
+    sys.modules[module_name] = shim
+
+
+def prepare_optional_dependency_import(name: str) -> None:
+    """Apply known import-time compatibility shims before probing a package."""
+    if name == "realesrgan":
+        patch_realesrgan_torchvision_compat()