fix: support simple Ruff extend

pyproject.toml

@@ -99,6 +99,7 @@ testpaths = ["tests"]
 
 
 [tool.mypy]
+mypy_path = ["src"]
 files = ["src", "tests"]
 python_version = "3.10"
 warn_unused_configs = true

src/sp_repo_review/checks/ruff.py

@@ -12,17 +12,31 @@
 ## R2xx: Ruff deprecations
 
 
+def merge(start: dict[str, Any], add: dict[str, Any]) -> dict[str, Any]:
+    merged = start.copy()
+    for key, value in add.items():
+        merged[key] = (
+            merge(start.get(key, {}), value) if isinstance(value, dict) else value
+        )
+    return merged
+
+
 def ruff(pyproject: dict[str, Any], root: Traversable) -> dict[str, Any] | None:
     """
     Returns the ruff configuration, or None if the configuration doesn't exist.
     Respects ``ruff.toml`` and ``.ruff.toml`` in addition to
-    ``pyproject.toml``.
+    ``pyproject.toml``. Respects the extend option.
     """
     paths = [root.joinpath(".ruff.toml"), root.joinpath("ruff.toml")]
     for path in paths:
         if path.is_file():
             with path.open("rb") as f:
-                return tomllib.load(f)
+                contents = tomllib.load(f)
+            if contents.get("extend", "") == "pyproject.toml":
+                extend = pyproject.get("tool", {}).get("ruff", {})
+                return merge(extend, contents)
+            return contents
+
     return pyproject.get("tool", {}).get("ruff", None)  # type: ignore[no-any-return]
 
 
@@ -35,13 +49,13 @@ class Ruff:
 class RF001(Ruff):
     "Has Ruff config"
 
-    requires = {"PY001"}
+    requires = set()
 
     @staticmethod
     def check(ruff: dict[str, Any] | None) -> bool:
         """
-        Must have `[tool.ruff]` section in `pyproject.toml`. Other forms of
-        configuration are not supported by this check.
+        Must have `[tool.ruff]` section in `pyproject.toml` or
+        `ruff.toml`/`.ruff.toml`.
         """
 
         return ruff is not None
@@ -102,8 +116,8 @@ def check(cls: type[RF1xxMixin], ruff: dict[str, Any]) -> bool:
         Must select the {self.name} `{self.code}` checks. Recommended:
 
         ```toml
-        [tool.ruff]
-        select = [
+        [tool.ruff.lint]
+        extend-select = [
           "{self.code}",  # {self.name}
         ]
         ```

tests/packages/ruff_extend/pyproject.toml

@@ -0,0 +1,5 @@
+[tool.repo-review]
+select = ["RF", "PY001"]
+
+[tool.ruff.lint]
+select = ["ALL"]

tests/packages/ruff_extend/ruff.toml

@@ -0,0 +1,2 @@
+extend = "pyproject.toml"
+target-version = "3.8"

tests/test_package.py

@@ -26,3 +26,12 @@ def test_local():
     package = DIR.parent
     results = process(package)
     assert results
+
+
+@pytest.mark.parametrize("name", ["ruff_extend"])
+def test_examples(name: str) -> None:
+    package = DIR / "packages" / name
+    _, results = process(package)
+
+    failures = [r for r in results if r.result is not None and not r.result]
+    assert not failures

tests/test_utils.py

@@ -0,0 +1,16 @@
+from __future__ import annotations
+
+from sp_repo_review.checks.ruff import merge
+
+
+def test_merge():
+    a = {"a": 1, "b": [1], "c": {"aa": 2, "bb": [2]}, "d": {"one": 1}}
+    b = {"b": [3], "c": {"bb": [4], "cc": 5}, "e": {"two": 2}}
+
+    assert merge(a, b) == {
+        "a": 1,
+        "b": [3],
+        "c": {"aa": 2, "bb": [4], "cc": 5},
+        "d": {"one": 1},
+        "e": {"two": 2},
+    }