Deprecate interfaces.implements

Author: DanielNoord

ChangeLog

@@ -114,6 +114,11 @@ Release date: TBA
 
   Ref #5392
 
+* ``interfaces.implements`` has been deprecated and will be removed in 3.0. Please use standard inheritance
+  patterns instead of ``__implements__``.
+
+  Ref #2287
+
 * ``invalid-enum-extension``: Used when a class tries to extend an inherited Enum class.
 
   Closes #5501

doc/whatsnew/2.14.rst

@@ -164,6 +164,11 @@ Other Changes
 
   Ref #5392
 
+* ``interfaces.implements`` has been deprecated and will be removed in 3.0. Please use standard inheritance
+  patterns instead of ``__implements__``.
+
+  Ref #2287
+
 * Added the ``generate-toml-config`` option.
 
   Ref #5462

pylint/checkers/base_checker.py

@@ -162,13 +162,15 @@ def check_consistency(self):
             existing_ids.append(message.msgid)
 
     def create_message_definition_from_tuple(self, msgid, msg_tuple):
-        if isinstance(self, (BaseTokenChecker, BaseRawFileChecker)):
-            default_scope = WarningScope.LINE
-        # TODO: Interfaces: Deprecate looking for implements here # pylint: disable=fixme
-        elif implements(self, (IRawChecker, ITokenChecker)):
-            default_scope = WarningScope.LINE
-        else:
-            default_scope = WarningScope.NODE
+        with warnings.catch_warnings():
+            warnings.filterwarnings("ignore", category=DeprecationWarning)
+            if isinstance(self, (BaseTokenChecker, BaseRawFileChecker)):
+                default_scope = WarningScope.LINE
+            # TODO: Interfaces: Deprecate looking for implements here # pylint: disable=fixme
+            elif implements(self, (IRawChecker, ITokenChecker)):
+                default_scope = WarningScope.LINE
+            else:
+                default_scope = WarningScope.NODE
         options = {}
         if len(msg_tuple) > 3:
             (msg, symbol, descr, options) = msg_tuple

pylint/interfaces.py

@@ -6,6 +6,7 @@
 
 from __future__ import annotations
 
+import warnings
 from collections import namedtuple
 from tokenize import TokenInfo
 from typing import TYPE_CHECKING
@@ -52,14 +53,22 @@ class Interface:
 
     @classmethod
     def is_implemented_by(cls, instance):
-        return implements(instance, cls)
+        with warnings.catch_warnings():
+            warnings.filterwarnings("ignore", category=DeprecationWarning)
+            return implements(instance, cls)
 
 
 def implements(
     obj: BaseChecker,
     interface: type[Interface] | tuple[type[Interface], ...],
 ) -> bool:
     """Does the given object (maybe an instance or class) implement the interface."""
+    # TODO: 3.0: Remove deprecated function # pylint: disable=fixme
+    warnings.warn(
+        "implements has been deprecated in favour of using basic "
+        "inheritance patterns without using __implements__.",
+        DeprecationWarning,
+    )
     implements_ = getattr(obj, "__implements__", ())
     if not isinstance(implements_, (list, tuple)):
         implements_ = (implements_,)

pylint/lint/pylinter.py

@@ -874,21 +874,25 @@ def _astroid_module_checker(self):
         """
         walker = ASTWalker(self)
         _checkers = self.prepare_checkers()
-        tokencheckers = [
-            c
-            for c in _checkers
-            if (
-                interfaces.implements(c, interfaces.ITokenChecker)
-                or isinstance(c, checkers.BaseTokenChecker)
-            )
-            and c is not self
-        ]
-        rawcheckers = [
-            c
-            for c in _checkers
-            if interfaces.implements(c, interfaces.IRawChecker)
-            or isinstance(c, checkers.BaseRawFileChecker)
-        ]
+        with warnings.catch_warnings():
+            warnings.filterwarnings("ignore", category=DeprecationWarning)
+            tokencheckers = [
+                c
+                for c in _checkers
+                if (
+                    interfaces.implements(c, interfaces.ITokenChecker)
+                    or isinstance(c, checkers.BaseTokenChecker)
+                )
+                and c is not self
+            ]
+        with warnings.catch_warnings():
+            warnings.filterwarnings("ignore", category=DeprecationWarning)
+            rawcheckers = [
+                c
+                for c in _checkers
+                if interfaces.implements(c, interfaces.IRawChecker)
+                or isinstance(c, checkers.BaseRawFileChecker)
+            ]
         # notify global begin
         for checker in _checkers:
             checker.open()