fix: Make extension paths relative to config file

PR #112: #112
Co-authored-by: Timothée Mazzucotelli <pawamoy@pm.me>

src/mkdocstrings_handlers/python/handler.py

@@ -9,7 +9,7 @@
 import sys
 from collections import ChainMap
 from contextlib import suppress
-from typing import TYPE_CHECKING, Any, BinaryIO, ClassVar, Iterator, Mapping
+from typing import TYPE_CHECKING, Any, BinaryIO, ClassVar, Iterator, Mapping, Sequence
 
 from griffe.collections import LinesCollection, ModulesCollection
 from griffe.docstrings.parsers import Parser
@@ -265,8 +265,9 @@ def collect(self, identifier: str, config: Mapping[str, Any]) -> CollectorItem:
         parser = parser_name and Parser(parser_name)
 
         if unknown_module:
+            extensions = self.normalize_extension_paths(final_config.get("extensions", []))
             loader = GriffeLoader(
-                extensions=load_extensions(final_config.get("extensions", [])),
+                extensions=load_extensions(extensions),
                 search_paths=self._paths,
                 docstring_parser=parser,
                 docstring_options=parser_options,
@@ -369,6 +370,35 @@ def get_anchors(self, data: CollectorItem) -> tuple[str, ...]:  # noqa: D102 (ig
             return tuple(anchors)
         return tuple(anchors)
 
+    def normalize_extension_paths(self, extensions: Sequence) -> Sequence:
+        """Resolve extension paths relative to config file."""
+        if self._config_file_path is None:
+            return extensions
+
+        base_path = os.path.dirname(self._config_file_path)
+        normalized = []
+
+        for ext in extensions:
+            if isinstance(ext, dict):
+                pth, options = next(iter(ext.items()))
+                pth = str(pth)
+            else:
+                pth = str(ext)
+                options = None
+
+            if pth.endswith(".py") or ".py:" in pth or "/" in pth or "\\" in pth:  # noqa: SIM102
+                # This is a sytem path. Normalize it.
+                if not os.path.isabs(pth):
+                    # Make path absolute relative to config file path.
+                    pth = os.path.normpath(os.path.join(base_path, pth))
+
+            if options is not None:
+                normalized.append({pth: options})
+            else:
+                normalized.append(pth)
+
+        return normalized
+
 
 def get_handler(
     *,

tests/test_handler.py

@@ -105,3 +105,43 @@ def test_expand_globs_without_changing_directory() -> None:
     )
     for path in list(glob(os.path.abspath(".") + "/*.md")):
         assert path in handler._paths
+
+
+@pytest.mark.parametrize(
+    ("expect_change", "extension"),
+    [
+        (True, "extension.py"),
+        (True, "extension.py:SomeExtension"),
+        (True, "path/to/extension.py"),
+        (True, "path/to/extension.py:SomeExtension"),
+        (True, {"extension.py": {"option": "value"}}),
+        (True, {"extension.py:SomeExtension": {"option": "value"}}),
+        (True, {"path/to/extension.py": {"option": "value"}}),
+        (True, {"path/to/extension.py:SomeExtension": {"option": "value"}}),
+        (False, "/absolute/path/to/extension.py"),
+        (False, "/absolute/path/to/extension.py:SomeExtension"),
+        (False, {"/absolute/path/to/extension.py": {"option": "value"}}),
+        (False, {"/absolute/path/to/extension.py:SomeExtension": {"option": "value"}}),
+        (False, "dot.notation.path.to.extension"),
+        (False, "dot.notation.path.to.pyextension"),
+        (False, {"dot.notation.path.to.extension": {"option": "value"}}),
+        (False, {"dot.notation.path.to.pyextension": {"option": "value"}}),
+    ],
+)
+def test_extension_paths(tmp_path: Path, expect_change: bool, extension: str | dict) -> None:
+    """Assert extension paths are resolved relative to config file."""
+    handler = get_handler(
+        theme="material",
+        config_file_path=str(tmp_path.joinpath("mkdocs.yml")),
+    )
+    normalized = handler.normalize_extension_paths([extension])[0]
+    if expect_change:
+        if isinstance(normalized, str) and isinstance(extension, str):
+            assert normalized == str(tmp_path.joinpath(extension))
+        elif isinstance(normalized, dict) and isinstance(extension, dict):
+            pth, options = next(iter(extension.items()))
+            assert normalized == {str(tmp_path.joinpath(pth)): options}
+        else:
+            raise ValueError("Normalization must not change extension items type")
+    else:
+        assert normalized == extension