Fix unhelpful message when a metadata file (fixes #1145)

CHANGELOG.rst

@@ -13,6 +13,7 @@ Release 0.14.0 (unreleased)
 * Add new ``remove`` command to remove projects from manifest and disk (#26)
 * Fix "unsafe symlink target" error for archives containing relative ``..`` symlinks (#1122)
 * Fix ``dfetch add`` crashing with a ``ValueError`` when the remote URL has a trailing slash (#1137)
+* Fix unhelpful message when a metadata file (#1145)
 
 Release 0.13.0 (released 2026-03-30)
 ====================================

dfetch/project/metadata.py

@@ -88,7 +88,11 @@ def from_project_entry(cls, project: ProjectEntry) -> "Metadata":
     def from_file(cls, path: str) -> "Metadata":
         """Load metadata file."""
         with open(path, encoding="utf-8") as metadata_file:
-            data: Options = yaml.safe_load(metadata_file)["dfetch"]
+            try:
+                data: Options = yaml.safe_load(metadata_file)["dfetch"]
+            except yaml.YAMLError as exc:
+                raise ValueError(str(exc)) from exc
+
             return cls(data)
 
     def fetched(

dfetch/project/subproject.py

@@ -348,7 +348,7 @@ def on_disk_version(self) -> Version | None:
 
         try:
             return Metadata.from_file(self.__metadata.path).version
-        except TypeError:
+        except (TypeError, ValueError):
             logger.print_warning_line(
                 self.__project.name,
                 f"{pathlib.Path(self.__metadata.path).relative_to(os.getcwd()).as_posix()}"
@@ -367,7 +367,7 @@ def _on_disk_hash(self) -> str | None:
 
         try:
             return Metadata.from_file(self.__metadata.path).hash
-        except TypeError:
+        except (TypeError, ValueError):
             logger.print_warning_line(
                 self.__project.name,
                 f"{pathlib.Path(self.__metadata.path).relative_to(os.getcwd()).as_posix()}"

features/handle-invalid-metadata.feature

@@ -6,6 +6,30 @@ Feature: Handle invalid metadata files
     to unpredictable behavior in *DFetch*.
     For instance, the metadata may be invalid
 
+    Scenario: Metadata with invalid YAML syntax is treated as invalid
+        Given the manifest 'dfetch.yaml'
+            """
+            manifest:
+              version: '0.0'
+
+              projects:
+                - name: ext/test-repo-tag
+                  url: https://github.com/dfetch-org/test-repo
+                  tag: v1
+
+            """
+        And all projects are updated
+        And the metadata file ".dfetch_data.yaml" of "ext/test-repo-tag" has invalid yaml
+        When I run "dfetch update"
+        Then the output shows
+            """
+            Dfetch (0.13.0)
+              ext/test-repo-tag:
+              > ext/test-repo-tag/.dfetch_data.yaml is an invalid metadata file, not checking on disk version!
+              > ext/test-repo-tag/.dfetch_data.yaml is an invalid metadata file, not checking local hash!
+              > Fetched v1
+            """
+
     Scenario: Invalid metadata is ignored
         Given the manifest 'dfetch.yaml'
             """

features/steps/generic_steps.py

@@ -282,6 +282,14 @@ def step_impl(_, metadata_file, project_path):
     )
 
 
+@given('the metadata file "{metadata_file}" of "{project_path}" has invalid yaml')
+def step_impl(_, metadata_file, project_path):
+    generate_file(
+        os.path.join(os.getcwd(), project_path, metadata_file),
+        "key: [unclosed bracket\n",
+    )
+
+
 @given('the metadata file "{metadata_file}" of "{project_path}" is changed')
 def step_impl(_, metadata_file, project_path):
     extend_file(