Validate pylock package index URLs

src/packaging/pylock.py

@@ -243,6 +243,15 @@ def _validate_path_url(path: str | None, url: str | None) -> None:
         raise PylockValidationError("path or url must be provided")
 
 
+def _validate_index_url(url: str) -> str:
+    parsed_url = urlparse(url)
+    if not parsed_url.scheme:
+        raise PylockValidationError(f"URL {url!r} must be absolute")
+    if parsed_url.scheme in {"http", "https"} and not parsed_url.netloc:
+        raise PylockValidationError(f"URL {url!r} must include a host")
+    return url
+
+
 def _path_name(path: str | None) -> str | None:
     if not path:
         return None
@@ -580,7 +589,7 @@ def _from_dict(cls, d: Mapping[str, Any]) -> Self:
             vcs=_get_object(d, PackageVcs, "vcs"),
             directory=_get_object(d, PackageDirectory, "directory"),
             archive=_get_object(d, PackageArchive, "archive"),
-            index=_get(d, str, "index"),
+            index=_get_as(d, str, _validate_index_url, "index"),
             sdist=_get_object(d, PackageSdist, "sdist"),
             wheels=_get_sequence_of_objects(d, PackageWheel, "wheels"),
             attestation_identities=_get_sequence(d, Mapping, "attestation-identities"),  # type: ignore[type-abstract]

tests/test_pylock.py

@@ -233,6 +233,58 @@ def test_pylock_basic_package() -> None:
     assert pylock.to_dict() == data
 
 
+@pytest.mark.parametrize("index", ["not-a-url", "https:///simple"])
+def test_pylock_invalid_package_index(index: str) -> None:
+    data = {
+        "lock-version": "1.0",
+        "created-by": "pip",
+        "packages": [
+            {
+                "name": "example",
+                "index": index,
+                "wheels": [
+                    {
+                        "name": "example-1.0-py3-none-any.whl",
+                        "url": "https://example.com/example-1.0-py3-none-any.whl",
+                        "hashes": {"sha256": "f" * 40},
+                    }
+                ],
+            }
+        ],
+    }
+    with pytest.raises(PylockValidationError) as exc_info:
+        Pylock.from_dict(data)
+    expected_error = (
+        f"URL {index!r} must be absolute"
+        if index == "not-a-url"
+        else f"URL {index!r} must include a host"
+    )
+    assert str(exc_info.value) == f"{expected_error} in 'packages[0].index'"
+
+
+def test_pylock_package_index_file_url() -> None:
+    data = {
+        "lock-version": "1.0",
+        "created-by": "pip",
+        "packages": [
+            {
+                "name": "example",
+                "index": "file:///tmp/simple/",
+                "wheels": [
+                    {
+                        "name": "example-1.0-py3-none-any.whl",
+                        "url": "https://example.com/example-1.0-py3-none-any.whl",
+                        "hashes": {"sha256": "f" * 40},
+                    }
+                ],
+            }
+        ],
+    }
+    pylock = Pylock.from_dict(data)
+    assert pylock.packages[0].index == "file:///tmp/simple/"
+    assert pylock.to_dict() == data
+
+
 def test_pylock_vcs_package() -> None:
     data = {
         "lock-version": "1.0",