Add base Checker classes mirroring interfaces

3 files changed, 25 insertions, 3 deletions

diff --git a/.coveragerc b/.coveragerc
index 871b6077e..faa494f8e 100644
--- a/.coveragerc
+++ b/.coveragerc
@@ -23,3 +23,6 @@ exclude_lines =
     # Type checking code not executed during pytest runs
     if TYPE_CHECKING:
     @overload
+
+    # Abstract methods are not exectued during pytest runs
+    raise NotImplementedError()
diff --git a/pylint/checkers/__init__.py b/pylint/checkers/__init__.py
index f0e679374..51393c400 100644
--- a/pylint/checkers/__init__.py
+++ b/pylint/checkers/__init__.py
@@ -45,7 +45,11 @@ from __future__ import annotations
 
 import sys
 
-from pylint.checkers.base_checker import BaseChecker, BaseTokenChecker
+from pylint.checkers.base_checker import (
+    BaseChecker,
+    BaseRawFileChecker,
+    BaseTokenChecker,
+)
 from pylint.checkers.deprecated import DeprecatedMixin
 from pylint.checkers.mapreduce_checker import MapReduceMixin
 from pylint.utils import LinterStats, diff_string, register_plugins
@@ -132,6 +136,7 @@ def initialize(linter):
 __all__ = [
     "BaseChecker",
     "BaseTokenChecker",
+    "BaseRawFileChecker",
     "initialize",
     "MapReduceMixin",
     "DeprecatedMixin",
diff --git a/pylint/checkers/base_checker.py b/pylint/checkers/base_checker.py
index fd01bfaa1..94b45ef48 100644
--- a/pylint/checkers/base_checker.py
+++ b/pylint/checkers/base_checker.py
@@ -4,6 +4,7 @@
 
 from __future__ import annotations
 
+import abc
 import functools
 import warnings
 from inspect import cleandoc
@@ -201,16 +202,29 @@ class BaseChecker(_ArgumentsProvider):
         error_msg += f"Choose from {[m.msgid for m in self.messages]}."
         raise InvalidMessageError(error_msg)
 
-    def open(self):
+    def open(self) -> None:
         """Called before visiting project (i.e. set of modules)."""
 
-    def close(self):
+    def close(self) -> None:
         """Called after visiting project (i.e set of modules)."""
 
 
 class BaseTokenChecker(BaseChecker):
     """Base class for checkers that want to have access to the token stream."""
 
+    @abc.abstractmethod
     def process_tokens(self, tokens: list[TokenInfo]) -> None:
         """Should be overridden by subclasses."""
         raise NotImplementedError()
+
+
+class BaseRawFileChecker(BaseChecker):
+    """Base class for checkers which need to parse the raw file."""
+
+    @abc.abstractmethod
+    def process_module(self, node: nodes.Module) -> None:
+        """Process a module.
+
+        The module's content is accessible via ``astroid.stream``
+        """
+        raise NotImplementedError()