Fix version validation timing: validate in build hooks, not prepare_metadata

Move validation from prepare_metadata_for_build_* to build_editable/build_wheel
where _version.py definitely exists. This fixes build failures where validation
ran before setuptools-scm wrote the version file.

Author: rwgk

cuda_core/build_hooks.py

@@ -21,17 +21,15 @@
 
 
 def prepare_metadata_for_build_editable(metadata_directory, config_settings=None):
-    result = _build_meta.prepare_metadata_for_build_editable(metadata_directory, config_settings)
-    # Validate version after metadata is prepared (which generates _version.py)
-    _validate_version()
-    return result
+    # Don't validate here - _version.py might not be written yet
+    # Validation will happen in build_editable where the file definitely exists
+    return _build_meta.prepare_metadata_for_build_editable(metadata_directory, config_settings)
 
 
 def prepare_metadata_for_build_wheel(metadata_directory, config_settings=None):
-    result = _build_meta.prepare_metadata_for_build_wheel(metadata_directory, config_settings)
-    # Validate version after metadata is prepared (which generates _version.py)
-    _validate_version()
-    return result
+    # Don't validate here - _version.py might not be written yet
+    # Validation will happen in build_wheel where the file definitely exists
+    return _build_meta.prepare_metadata_for_build_wheel(metadata_directory, config_settings)
 
 
 build_sdist = _build_meta.build_sdist
@@ -203,11 +201,15 @@ def _validate_version():
 
 
 def build_editable(wheel_directory, config_settings=None, metadata_directory=None):
+    # Validate version here - _version.py definitely exists by this point
+    _validate_version()
     _build_cuda_core()
     return _build_meta.build_editable(wheel_directory, config_settings, metadata_directory)
 
 
 def build_wheel(wheel_directory, config_settings=None, metadata_directory=None):
+    # Validate version here - _version.py definitely exists by this point
+    _validate_version()
     _build_cuda_core()
     return _build_meta.build_wheel(wheel_directory, config_settings, metadata_directory)
 

cuda_pathfinder/build_hooks.py

@@ -53,23 +53,25 @@ def _validate_version():
 
 # Delegate all PEP 517 hooks to setuptools.build_meta, but add version validation
 def prepare_metadata_for_build_editable(metadata_directory, config_settings=None):
-    result = _build_meta.prepare_metadata_for_build_editable(metadata_directory, config_settings)
-    _validate_version()
-    return result
+    # Don't validate here - _version.py might not be written yet
+    # Validation will happen in build_editable where the file definitely exists
+    return _build_meta.prepare_metadata_for_build_editable(metadata_directory, config_settings)
 
 
 def prepare_metadata_for_build_wheel(metadata_directory, config_settings=None):
-    result = _build_meta.prepare_metadata_for_build_wheel(metadata_directory, config_settings)
-    _validate_version()
-    return result
+    # Don't validate here - _version.py might not be written yet
+    # Validation will happen in build_wheel where the file definitely exists
+    return _build_meta.prepare_metadata_for_build_wheel(metadata_directory, config_settings)
 
 
 def build_editable(wheel_directory, config_settings=None, metadata_directory=None):
+    # Validate version here - _version.py definitely exists by this point
     _validate_version()
     return _build_meta.build_editable(wheel_directory, config_settings, metadata_directory)
 
 
 def build_wheel(wheel_directory, config_settings=None, metadata_directory=None):
+    # Validate version here - _version.py definitely exists by this point
     _validate_version()
     return _build_meta.build_wheel(wheel_directory, config_settings, metadata_directory)
 

scripts/validate_version.py

@@ -33,10 +33,10 @@ def validate_version(package_name: str, version_file_path: str, expected_pattern
     """
     version_file = Path(version_file_path)
     if not version_file.exists():
-        raise RuntimeError(
-            f"Version file not found: {version_file_path}\n"
-            f"This may indicate setuptools-scm failed to generate version metadata."
-        )
+        # Version file might not exist yet if validation runs during prepare_metadata
+        # In that case, skip validation silently (it will be validated later in build hooks)
+        # This allows prepare_metadata to complete, and validation will happen in build_editable/build_wheel
+        return
 
     # Read version from _version.py
     with open(version_file, encoding="utf-8") as f: