Create additional Namespaces for subdirectories with configuration files

Closes pylint-dev#618

pylint/config/arguments_manager.py

@@ -81,6 +81,9 @@ def __init__(
         self._directory_namespaces: DirectoryNamespaceDict = {}
         """Mapping of directories and their respective namespace objects."""
 
+        self._cli_args: list[str] = []
+        """Options that were passed as command line arguments and have highest priority."""
+
     @property
     def config(self) -> argparse.Namespace:
         """Namespace for all options."""
@@ -226,6 +229,8 @@ def _parse_command_line_configuration(
     ) -> list[str]:
         """Parse the arguments found on the command line into the namespace."""
         arguments = sys.argv[1:] if arguments is None else arguments
+        if not self._cli_args:
+            self._cli_args = list(arguments)
 
         self.config, parsed_args = self._arg_parser.parse_known_args(
             arguments, self.config

pylint/config/find_default_config_files.py

@@ -64,17 +64,19 @@ def _cfg_has_config(path: Path | str) -> bool:
     return any(section.startswith("pylint.") for section in parser.sections())
 
 
-def _yield_default_files() -> Iterator[Path]:
+def _yield_default_files(basedir: Path | str = ".") -> Iterator[Path]:
     """Iterate over the default config file names and see if they exist."""
+    basedir = Path(basedir)
     for config_name in CONFIG_NAMES:
+        config_file = basedir / config_name
         try:
-            if config_name.is_file():
-                if config_name.suffix == ".toml" and not _toml_has_config(config_name):
+            if config_file.is_file():
+                if config_file.suffix == ".toml" and not _toml_has_config(config_file):
                     continue
-                if config_name.suffix == ".cfg" and not _cfg_has_config(config_name):
+                if config_file.suffix == ".cfg" and not _cfg_has_config(config_file):
                     continue
 
-                yield config_name.resolve()
+                yield config_file.resolve()
         except OSError:
             pass
 
@@ -142,3 +144,8 @@ def find_default_config_files() -> Iterator[Path]:
             yield Path("/etc/pylintrc").resolve()
     except OSError:
         pass
+
+
+def find_subdirectory_config_files(basedir: Path | str) -> Iterator[Path]:
+    """Find config file in arbitrary subdirectory."""
+    yield from _yield_default_files(basedir)

pylint/lint/base_options.py

@@ -414,6 +414,25 @@ def _make_linter_options(linter: PyLinter) -> Options:
                 "Useful if running pylint in a server-like mode.",
             },
         ),
+        (
+            "use-local-configs",
+            {
+                "default": False,
+                "type": "yn",
+                "metavar": "<y or n>",
+                "help": "When some of the linted files or modules have pylint config in the same directory, "
+                "use their local configs for checking these files.",
+            },
+        ),
+        (
+            "use-parent-configs",
+            {
+                "default": False,
+                "type": "yn",
+                "metavar": "<y or n>",
+                "help": "Search for local pylint configs up until current working directory or root.",
+            },
+        ),
     )
 
 

pylint/lint/pylinter.py

@@ -26,6 +26,8 @@
 from pylint import checkers, exceptions, interfaces, reporters
 from pylint.checkers.base_checker import BaseChecker
 from pylint.config.arguments_manager import _ArgumentsManager
+from pylint.config.config_initialization import _config_initialization
+from pylint.config.find_default_config_files import find_subdirectory_config_files
 from pylint.constants import (
     MAIN_CHECKER_NAME,
     MSG_TYPES,
@@ -616,6 +618,37 @@ def initialize(self) -> None:
             if not msg.may_be_emitted(self.config.py_version):
                 self._msgs_state[msg.msgid] = False
 
+    def register_local_config(self, file_or_dir: str) -> None:
+        if os.path.isdir(file_or_dir):
+            basedir = Path(file_or_dir)
+        else:
+            basedir = Path(os.path.dirname(file_or_dir))
+
+        if self.config.use_parent_configs is False:
+            # exit loop after first iteration
+            scan_root_dir = basedir
+        elif _is_relative_to(basedir, Path(os.getcwd())):
+            scan_root_dir = Path(os.getcwd())
+        else:
+            scan_root_dir = Path("/")
+
+        while basedir.resolve() not in self._directory_namespaces and _is_relative_to(
+            basedir, scan_root_dir
+        ):
+            local_conf = next(find_subdirectory_config_files(basedir), None)
+            if local_conf is not None:
+                _config_initialization(self, self._cli_args, config_file=local_conf)
+                self._directory_namespaces[Path(basedir).resolve()] = (
+                    self.config,
+                    {},
+                )
+                self.config = self._base_config
+                break
+            if basedir.parent != basedir:
+                basedir = basedir.parent
+            else:
+                break
+
     def _discover_files(self, files_or_modules: Sequence[str]) -> Iterator[str]:
         """Discover python modules and packages in sub-directory.
 
@@ -666,12 +699,15 @@ def check(self, files_or_modules: Sequence[str]) -> None:
                     "Missing filename required for --from-stdin"
                 )
 
-        extra_packages_paths = list(
-            {
+        if self.config.use_local_configs is True:
+            for file_or_module in files_or_modules:
+                self.register_local_config(file_or_module)
+        extra_packages_paths_set = set()
+        for file_or_module in files_or_modules:
+            extra_packages_paths_set.add(
                 discover_package_path(file_or_module, self.config.source_roots)
-                for file_or_module in files_or_modules
-            }
-        )
+            )
+        extra_packages_paths = list(extra_packages_paths_set)
 
         # TODO: Move the parallel invocation into step 3 of the checking process
         if not self.config.from_stdin and self.config.jobs > 1: