package_managers: generic: Use a serializer for URL-typed fields

Pydantic formats down URL types as "type casts" in the serialized
dictionary [1]. Apparently, that's by design and the docs advises to
use custom serializers for given fields [2].

This patch is necessary, because pydantic 2.10.2 changed their behavior
when it comes to handling URL types [3] and so once we bump the version
we'd hit a test failure requiring us to change the unit test to "cast"
some fields as AnyUrl rather than Url. Since these have no place in
plain dictionaries, this patch fixes the problem in the correct way by
the use of pydantic serializers.

[1] pydantic/pydantic#10998
[2] https://docs.pydantic.dev/latest/api/functional_serializers/#pydantic.functional_serializers.PlainSerializer
[3] https://pydantic.dev/articles/pydantic-v2-10-release#migrate-to-subclassing-instead-of-annotated-approach-for-pydantic-url-types

Signed-off-by: Erik Skultety <[email protected]>

cachi2/core/package_managers/generic/models.py

@@ -7,8 +7,16 @@
 from urllib.parse import urljoin, urlparse
 
 from packageurl import PackageURL
-from pydantic import AnyUrl, BaseModel, ConfigDict, field_validator, model_validator
+from pydantic import (
+    AnyUrl,
+    BaseModel,
+    ConfigDict,
+    PlainSerializer,
+    field_validator,
+    model_validator,
+)
 from pydantic_core.core_schema import ValidationInfo
+from typing_extensions import Annotated
 
 from cachi2.core.checksum import ChecksumInfo
 from cachi2.core.errors import PackageManagerError
@@ -88,7 +96,7 @@ class LockfileArtifactUrl(LockfileArtifactBase):
     :param download_url: The URL to download the artifact from.
     """
 
-    download_url: AnyUrl
+    download_url: Annotated[AnyUrl, PlainSerializer(str, return_type=str)]
 
     def resolve_filename(self) -> str:
         """Resolve the filename of the artifact."""
@@ -120,7 +128,7 @@ def get_sbom_component(self) -> Component:
 class LockfileArtifactMavenAttributes(BaseModel):
     """Attributes for a Maven artifact in the lockfile."""
 
-    repository_url: AnyUrl
+    repository_url: Annotated[AnyUrl, PlainSerializer(str, return_type=str)]
     group_id: str
     artifact_id: str
     version: str

tests/unit/package_managers/test_generic.py

@@ -3,7 +3,6 @@
 from unittest import mock
 
 import pytest
-from pydantic_core import Url
 
 from cachi2.core.errors import Cachi2Error, PackageRejected
 from cachi2.core.models.input import GenericPackageInput
@@ -335,15 +334,13 @@ def test_load_generic_lockfile_valid(rooted_tmp_path: RootedPath) -> None:
         "metadata": {"version": "1.0"},
         "artifacts": [
             {
-                "download_url": Url("https://example.com/artifact"),
+                "download_url": "https://example.com/artifact",
                 "filename": str(rooted_tmp_path.join_within_root("archive.zip")),
                 "checksum": "md5:3a18656e1cea70504b905836dee14db0",
             },
             {
                 "checksum": "md5:32112bed1914cfe3799600f962750b1d",
-                "download_url": Url(
-                    "https://example.com/more/complex/path/file.tar.gz?foo=bar#fragment"
-                ),
+                "download_url": "https://example.com/more/complex/path/file.tar.gz?foo=bar#fragment",
                 "filename": str(rooted_tmp_path.join_within_root("file.tar.gz")),
             },
         ],