[primer] Fall back to no rcfile rather than pylint's (#7798)

Author: jacobtylerwalls

pylint/testutils/_primer/package_to_lint.py

@@ -5,11 +5,17 @@
 from __future__ import annotations
 
 import logging
+import sys
 from pathlib import Path
 
 from git.cmd import Git
 from git.repo import Repo
 
+if sys.version_info >= (3, 8):
+    from typing import Literal
+else:
+    from typing_extensions import Literal
+
 PRIMER_DIRECTORY_PATH = Path("tests") / ".pylint_primer_tests"
 
 
@@ -56,9 +62,10 @@ def __init__(
         self.minimum_python = minimum_python
 
     @property
-    def pylintrc(self) -> Path | None:
+    def pylintrc(self) -> Path | Literal[""]:
         if self.pylintrc_relpath is None:
-            return None
+            # Fall back to "" to ensure pylint's own pylintrc is not discovered
+            return ""
         return self.clone_directory / self.pylintrc_relpath
 
     @property
@@ -75,9 +82,8 @@ def paths_to_lint(self) -> list[str]:
     @property
     def pylint_args(self) -> list[str]:
         options: list[str] = []
-        if self.pylintrc is not None:
-            # There is an error if rcfile is given but does not exist
-            options += [f"--rcfile={self.pylintrc}"]
+        # There is an error if rcfile is given but does not exist
+        options += [f"--rcfile={self.pylintrc}"]
         return self.paths_to_lint + options + self.pylint_additional_args
 
     def lazy_clone(self) -> str:  # pragma: no cover

tests/testutils/_primer/test_package_to_lint.py

@@ -42,8 +42,8 @@ def test_package_to_lint_default_value() -> None:
         branch="main",
         directories=["src/flask"],  # Must work on Windows (src\\flask)
     )
-    assert package_to_lint.pylintrc is None
+    assert package_to_lint.pylintrc == ""
     expected_path_to_lint = (
         PRIMER_DIRECTORY_PATH / "pallets" / "flask" / "src" / "flask"
     )
-    assert package_to_lint.pylint_args == [str(expected_path_to_lint)]
+    assert package_to_lint.pylint_args == [str(expected_path_to_lint), "--rcfile="]