Allow overwrite when schemas refer to the same tool

src/validate_pyproject/api.py

@@ -109,11 +109,16 @@ def __init__(self, plugins: Sequence["PluginProtocol"] = ()):
 
         # Add tools using Plugins
         for plugin in plugins:
+            allow_overwrite: Optional[str] = None
             if plugin.tool in tool_properties:
                 _logger.warning(f"{plugin.id} overwrites `tool.{plugin.tool}` schema")
+                allow_overwrite = plugin.schema.get("$id")
             else:
                 _logger.info(f"{plugin.id} defines `tool.{plugin.tool}` schema")
-            sid = self._ensure_compatibility(plugin.tool, plugin.schema)["$id"]
+            compatible = self._ensure_compatibility(
+                plugin.tool, plugin.schema, allow_overwrite
+            )
+            sid = compatible["$id"]
             sref = f"{sid}#{plugin.fragment}" if plugin.fragment else sid
             tool_properties[plugin.tool] = {"$ref": sref}
             self._schemas[sid] = (f"tool.{plugin.tool}", plugin.id, plugin.schema)
@@ -133,11 +138,13 @@ def main(self) -> str:
         """Top level schema for validating a ``pyproject.toml`` file"""
         return self._main_id
 
-    def _ensure_compatibility(self, reference: str, schema: Schema) -> Schema:
-        if "$id" not in schema:
+    def _ensure_compatibility(
+        self, reference: str, schema: Schema, allow_overwrite: Optional[str] = None
+    ) -> Schema:
+        if "$id" not in schema or not schema["$id"]:
             raise errors.SchemaMissingId(reference)
         sid = schema["$id"]
-        if sid in self._schemas:
+        if sid in self._schemas and sid != allow_overwrite:
             raise errors.SchemaWithDuplicatedId(sid)
         version = schema.get("$schema")
         # Support schemas with missing trailing # (incorrect, but required before 0.15)

src/validate_pyproject/plugins/__init__.py

@@ -90,7 +90,9 @@ def iterate_entry_points(group: str = ENTRYPOINT_GROUP) -> Iterable[EntryPoint]:
         # TODO: Once Python 3.10 becomes the oldest version supported, this fallback and
         #       conditional statement can be removed.
         entries_ = (plugin for plugin in entries.get(group, []))
-    deduplicated = {e.name: e for e in sorted(entries_, key=lambda e: e.name)}
+    deduplicated = {
+        e.name: e for e in sorted(entries_, key=lambda e: (e.name, e.value))
+    }
     return list(deduplicated.values())
 
 

tests/test_api.py

@@ -63,11 +63,19 @@ def test_incompatible_versions(self):
         with pytest.raises(errors.InvalidSchemaVersion):
             api.SchemaRegistry([plg])
 
-    def test_duplicated_id(self):
-        plg = [plugins.PluginWrapper("plg", self.fake_plugin) for _ in range(2)]
+    def test_duplicated_id_different_tools(self):
+        schema = self.fake_plugin("plg")
+        fn = wraps(self.fake_plugin)(lambda _: schema)  # Same ID
+        plg = [plugins.PluginWrapper(f"plg{i}", fn) for i in range(2)]
         with pytest.raises(errors.SchemaWithDuplicatedId):
             api.SchemaRegistry(plg)
 
+    def test_allow_overwrite_same_tool(self):
+        plg = [plugins.PluginWrapper("plg", self.fake_plugin) for _ in range(2)]
+        registry = api.SchemaRegistry(plg)
+        sid = self.fake_plugin("plg")["$id"]
+        assert sid in registry
+
     def test_missing_id(self):
         def _fake_plugin(name):
             plg = dict(self.fake_plugin(name))