fix: Defer creating module finder until first load

Issue-410: #410
PR-411: #411
Co-authored-by: Timothée Mazzucotelli <dev@pawamoy.fr>

Author: johnslavik

src/griffe/_internal/loader.py

@@ -9,6 +9,7 @@
 import tempfile
 from contextlib import suppress
 from datetime import datetime, timezone
+from functools import cached_property
 from importlib.util import find_spec
 from pathlib import Path
 from typing import TYPE_CHECKING, ClassVar, cast
@@ -90,13 +91,17 @@ def __init__(
         """Whether to force inspecting (importing) modules, even when sources were found."""
         self.store_source: bool = store_source
         """Whether to store source code in the lines collection."""
-        self.finder: ModuleFinder = ModuleFinder(search_paths)
-        """The module source finder."""
+        self._search_paths: Sequence[str | Path] | None = search_paths
         self._time_stats: dict = {
             "time_spent_visiting": 0,
             "time_spent_inspecting": 0,
         }
 
+    @cached_property
+    def finder(self) -> ModuleFinder:
+        """The module source finder."""
+        return ModuleFinder(search_paths=self._search_paths)
+
     def load(
         self,
         objspec: str | Path | None = None,

tests/test_loader.py

@@ -519,3 +519,14 @@ def test_loading_utf8_with_bom_files(tmp_path: Path) -> None:
     loader = GriffeLoader(search_paths=[tmp_path])
     package = loader.load("pkg")
     assert "func" in package.members  # Just checking all went well, no SyntaxError exceptions raised.
+
+
+def test_deferred_finder(tmp_path: Path) -> None:
+    """Check that the deferred finder works as expected."""
+    ns = tmp_path / "ns"
+    l1 = GriffeLoader(search_paths=[tmp_path])
+    ns.mkdir(exist_ok=False)
+    l2 = GriffeLoader(search_paths=[tmp_path])
+    l1_result = l1.load("ns")
+    l2_result = l2.load("ns")
+    assert l1_result.as_dict() == l2_result.as_dict()