Add test for Git LFS repository cloning

Verifies that Poetry can successfully clone Git repositories that use
Git Large File Storage (LFS) and that LFS files are properly retrieved
with their actual content rather than just pointer files.

This test uses dulwich's built-in LFS support to create a repository
with LFS files and verifies that cloning works correctly without
requiring manual configuration.

Note that while LFS support works in Dulwich >=1, the tests specifically
rely on it being able to use locally cloned LFS stores,
which requires dulwich 1.2.1.

Fixes #8723

Author: jelmer

pyproject.toml

@@ -79,6 +79,7 @@ pytest-cov = ">=4.0"
 pytest-mock = ">=3.9"
 pytest-randomly = ">=3.12"
 pytest-xdist = { version = ">=3.1", extras = ["psutil"] }
+dulwich = ">=1.2.1"
 
 [tool.poetry.group.typing.dependencies]
 mypy = ">=1.8.0"

tests/vcs/git/test_backend.py

@@ -453,3 +453,79 @@ def test_clone_legacy_strips_ref_prefixes(
 
     mock_clone.assert_called_once()
     mock_checkout.assert_called_once_with(expected_checkout, target)
+
+
+@pytest.mark.skip_git_mock
+def test_clone_with_lfs_files(tmp_path: Path) -> None:
+    """Test cloning a repository with Git LFS files (issue #8723)."""
+    from dulwich import porcelain
+    from dulwich.lfs import LFSStore
+
+    # Create a source repository with LFS support
+    source_path = tmp_path / "source-repo"
+    source_path.mkdir()
+    repo = Repo.init(str(source_path))
+
+    # Set up LFS in the repository
+    lfs_dir = source_path / ".git" / "lfs"
+    lfs_dir.mkdir(parents=True)
+    lfs_store = LFSStore.create(str(lfs_dir))
+
+    # Configure .gitattributes to track large files with LFS
+    gitattributes = source_path / ".gitattributes"
+    gitattributes.write_text("*.bin filter=lfs diff=lfs merge=lfs -text\n")
+    porcelain.add(repo, str(gitattributes))
+
+    # Create a regular file
+    regular_file = source_path / "regular.txt"
+    regular_file.write_text("This is a regular file")
+    porcelain.add(repo, str(regular_file))
+
+    # Create an LFS file with a pointer
+    lfs_content = b"This is a large binary file content for LFS storage"
+    lfs_file = source_path / "large.bin"
+
+    # Store the actual content in LFS store and create pointer
+    lfs_object_id = lfs_store.write_object([lfs_content])
+    lfs_pointer = (
+        f"version https://git-lfs.github.com/spec/v1\n"
+        f"oid sha256:{lfs_object_id}\n"
+        f"size {len(lfs_content)}\n"
+    )
+    lfs_file.write_text(lfs_pointer)
+    porcelain.add(repo, str(lfs_file))
+
+    # Commit the files
+    porcelain.commit(
+        repo,
+        message=b"Add files with LFS support",
+        author=b"Test <test@example.com>",
+        committer=b"Test <test@example.com>",
+    )
+
+    # Clone the repository
+    source_root_dir = tmp_path / "clone-root"
+    source_root_dir.mkdir()
+    Git.clone(
+        url=source_path.as_uri(),
+        source_root=source_root_dir,
+        name="clone-test",
+    )
+
+    # Verify the clone succeeded
+    clone_dir = source_root_dir / "clone-test"
+    assert (clone_dir / ".git").is_dir()
+
+    # Verify regular file is present
+    assert (clone_dir / "regular.txt").exists()
+    assert (clone_dir / "regular.txt").read_text() == "This is a regular file"
+
+    # Verify .gitattributes is present
+    assert (clone_dir / ".gitattributes").exists()
+    assert "filter=lfs" in (clone_dir / ".gitattributes").read_text()
+
+    # Verify LFS file is present with actual content (not just pointer)
+    # The LFS system should automatically retrieve the actual content
+    assert (clone_dir / "large.bin").exists()
+    lfs_file_content = (clone_dir / "large.bin").read_bytes()
+    assert lfs_file_content == lfs_content