Make object store close() idempotent and warn on unclosed resources

NEWS

@@ -3,6 +3,10 @@
  * Fix test failure when GPG raises ``InvalidSigners`` instead of
    ``GPGMEError`` on systems without usable secret keys. (#2063)
 
+ * Object store ``close()`` methods can now be called multiple times safely.
+   Object stores now raise ``ResourceWarning`` when destroyed with unclosed
+   resources. (Jelmer Vernooij)
+
 0.25.1	2026-01-08
 
  * Add signature vendor system for signing and verifying Git objects.

dulwich/dumb.py

@@ -362,12 +362,31 @@ class DumbHTTPObjectStore(BaseObjectStore):
         """Add a set of objects to this object store."""
         raise NotImplementedError("Cannot add objects to dumb HTTP repository")
 
-    def __del__(self) -> None:
-        """Clean up temporary directory on deletion."""
-        if self._temp_pack_dir and os.path.exists(self._temp_pack_dir):
-            import shutil
+    def close(self) -> None:
+        """Close the object store and release resources.
+
+        This method cleans up the temporary pack directory.
+        Can be called multiple times safely.
+        """
+        if self._temp_pack_dir is not None:
+            if os.path.exists(self._temp_pack_dir):
+                import shutil
 
-            shutil.rmtree(self._temp_pack_dir, ignore_errors=True)
+                shutil.rmtree(self._temp_pack_dir, ignore_errors=True)
+            self._temp_pack_dir = None
+
+    def __del__(self) -> None:
+        """Warn if the object store is being deleted without closing."""
+        if self._temp_pack_dir is not None:
+            import warnings
+
+            warnings.warn(
+                f"DumbHTTPObjectStore {self!r} was destroyed without calling close(). "
+                "Temporary pack directory may not be cleaned up properly.",
+                ResourceWarning,
+                stacklevel=2,
+            )
+            self.close()
 
 
 class DumbRemoteHTTPRepo:

dulwich/object_store.py

@@ -847,7 +847,6 @@ class PackBasedObjectStore(PackCapableObjectStore, PackedObjectContainer):
         """
         super().__init__(object_format=object_format)
         self._pack_cache: dict[str, Pack] = {}
-        self._closed = False
         self.pack_compression_level = pack_compression_level
         self.pack_index_version = pack_index_version
         self.pack_delta_window_size = pack_delta_window_size
@@ -1011,15 +1010,26 @@ class PackBasedObjectStore(PackCapableObjectStore, PackedObjectContainer):
         """Close the object store and release resources.
 
         This method closes all cached pack files and frees associated resources.
+        Can be called multiple times safely.
         """
-        self._closed = True
         self._clear_cached_packs()
 
+    def __del__(self) -> None:
+        """Warn if the object store is being deleted with unclosed packs."""
+        if self._pack_cache:
+            import warnings
+
+            warnings.warn(
+                f"ObjectStore {self!r} was destroyed with {len(self._pack_cache)} "
+                "unclosed pack(s). Please call close() explicitly.",
+                ResourceWarning,
+                stacklevel=2,
+            )
+            self.close()
+
     @property
     def packs(self) -> list[Pack]:
         """List with pack objects."""
-        if self._closed:
-            raise ValueError("Cannot access packs on a closed object store")
         return list(self._iter_cached_packs()) + list(self._update_pack_cache())
 
     def count_pack_files(self) -> int:
@@ -2437,6 +2447,7 @@ class DiskObjectStore(PackBasedObjectStore):
         """Close the object store and release resources.
 
         This method closes all cached pack files, MIDX, and frees associated resources.
+        Can be called multiple times safely.
         """
         # Close MIDX if it's loaded
         if self._midx is not None: