Refactor and deprecate resolving of interface implementations in `pyreverse` (#6713)

* Remove variables and code paths that are always static in productive use.

* Add deprecation warning if an interface defined through ``__implements__`` is found.

* Update pylint/pyreverse/inspector.py

Co-authored-by: Pierre Sassoulas <pierre.sassoulas@gmail.com>

* Group changelog entries together with refactor from #6712

Co-authored-by: Pierre Sassoulas <pierre.sassoulas@gmail.com>

4 files changed, 47 insertions, 29 deletions

diff --git a/ChangeLog b/ChangeLog
index 0fb600683..46731bf91 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -181,6 +181,11 @@ Release date: TBA
 
   Ref #6712
 
+* ``pyreverse``: Resolving and displaying implemented interfaces that are defined by the ``__implements__``
+  attribute has been deprecated and will be removed in 3.0.
+
+  Ref #6713
+
 * ``interfaces.implements`` has been deprecated and will be removed in 3.0. Please use standard inheritance
   patterns instead of ``__implements__``.
 
diff --git a/doc/whatsnew/2.14.rst b/doc/whatsnew/2.14.rst
index 3e4fd87e6..d5caee73a 100644
--- a/doc/whatsnew/2.14.rst
+++ b/doc/whatsnew/2.14.rst
@@ -281,10 +281,6 @@ Other Changes
 
   Closes #6644
 
-* ``pylint.pyreverse.ASTWalker`` has been removed, as it was only used internally by a single child class.
-
-  Ref #6712
-
 
 Deprecations
 ============
@@ -387,6 +383,15 @@ Deprecations
 
   Ref #5392
 
+* ``pylint.pyreverse.ASTWalker`` has been removed, as it was only used internally by a single child class.
+
+  Ref #6712
+
+* ``pyreverse``: Resolving and displaying implemented interfaces that are defined by the ``__implements__``
+  attribute has been deprecated and will be removed in 3.0.
+
+  Ref #6713
+
 * ``is_class_subscriptable_pep585_with_postponed_evaluation_enabled`` has been deprecated.
   Use ``is_postponed_evaluation_enabled(node) and is_node_in_type_annotation_context(node)``
   instead.
diff --git a/pylint/pyreverse/inspector.py b/pylint/pyreverse/inspector.py
index 35e993f11..8f0f9bcfc 100644
--- a/pylint/pyreverse/inspector.py
+++ b/pylint/pyreverse/inspector.py
@@ -12,6 +12,7 @@ from __future__ import annotations
 import collections
 import os
 import traceback
+import warnings
 from collections.abc import Generator
 from typing import Any, Callable, Optional
 
@@ -24,11 +25,6 @@ from pylint.pyreverse import utils
 _WrapperFuncT = Callable[[Callable[[str], nodes.Module], str], Optional[nodes.Module]]
 
 
-def _iface_hdlr(_: nodes.NodeNG | Any) -> bool:
-    """Handler used by interfaces to handle suspicious interface nodes."""
-    return True
-
-
 def _astroid_wrapper(
     func: Callable[[str], nodes.Module], modname: str
 ) -> nodes.Module | None:
@@ -42,17 +38,13 @@ def _astroid_wrapper(
     return None
 
 
-def interfaces(
-    node: nodes.ClassDef,
-    herited: bool = True,
-    handler_func: Callable[[nodes.NodeNG | Any], bool] = _iface_hdlr,
-) -> Generator[Any, None, None]:
+def interfaces(node: nodes.ClassDef) -> Generator[Any, None, None]:
     """Return an iterator on interfaces implemented by the given class node."""
     try:
         implements = astroid.bases.Instance(node).getattr("__implements__")[0]
     except astroid.exceptions.NotFoundError:
         return
-    if not herited and implements.frame(future=True) is not node:
+    if implements.frame(future=True) is not node:
         return
     found = set()
     missing = False
@@ -60,7 +52,7 @@ def interfaces(
         if iface is astroid.Uninferable:
             missing = True
             continue
-        if iface not in found and handler_func(iface):
+        if iface not in found:
             found.add(iface)
             yield iface
     if missing:
@@ -135,13 +127,9 @@ class Linker(IdGeneratorMixIn, utils.LocalsVisitor):
       list of implemented interface _objects_ (only on astroid.Class nodes)
     """
 
-    def __init__(
-        self, project: Project, inherited_interfaces: bool = False, tag: bool = False
-    ) -> None:
+    def __init__(self, project: Project, tag: bool = False) -> None:
         IdGeneratorMixIn.__init__(self)
         utils.LocalsVisitor.__init__(self)
-        # take inherited interface in consideration or not
-        self.inherited_interfaces = inherited_interfaces
         # tag nodes or not
         self.tag = tag
         # visited project
@@ -196,8 +184,18 @@ class Linker(IdGeneratorMixIn, utils.LocalsVisitor):
                     self.handle_assignattr_type(assignattr, node)
         # resolve implemented interface
         try:
-            ifaces = interfaces(node, self.inherited_interfaces)
-            node.implements = list(ifaces) if ifaces is not None else []
+            ifaces = interfaces(node)
+            if ifaces is not None:
+                node.implements = list(ifaces)
+                # TODO: 3.0: Remove support for __implements__
+                warnings.warn(
+                    "pyreverse will drop support for resolving and displaying implemented interfaces in pylint 3.0. "
+                    "The implementation relies on the '__implements__'  attribute proposed in PEP 245, which was rejected "
+                    "in 2006.",
+                    DeprecationWarning,
+                )
+            else:
+                node.implements = []
         except astroid.InferenceError:
             node.implements = []
 
@@ -213,11 +211,6 @@ class Linker(IdGeneratorMixIn, utils.LocalsVisitor):
         if self.tag:
             node.uid = self.generate_id()
 
-    link_project = visit_project
-    link_module = visit_module
-    link_class = visit_classdef
-    link_function = visit_functiondef
-
     def visit_assignname(self, node: nodes.AssignName) -> None:
         """Visit an astroid.AssignName node.
 
diff --git a/tests/pyreverse/test_inspector.py b/tests/pyreverse/test_inspector.py
index db0f4656a..0fd54e8f8 100644
--- a/tests/pyreverse/test_inspector.py
+++ b/tests/pyreverse/test_inspector.py
@@ -110,7 +110,7 @@ def test_interfaces() -> None:
         ("Concrete0", ["MyIFace"]),
         ("Concrete1", ["MyIFace", "AnotherIFace"]),
         ("Concrete2", ["MyIFace", "AnotherIFace"]),
-        ("Concrete23", ["MyIFace", "AnotherIFace"]),
+        ("Concrete23", []),
     ):
         klass = module[klass]
         assert [i.name for i in inspector.interfaces(klass)] == interfaces
@@ -130,3 +130,18 @@ def test_project_node(project: Project) -> None:
         "data.suppliermodule_test",
     ]
     assert sorted(project.keys()) == expected
+
+
+def test_interface_deprecation(project: Project) -> None:
+    linker = inspector.Linker(project)
+    cls = astroid.extract_node(
+        '''
+        class IMachin: pass
+
+        class Concrete:  #@
+            """docstring"""
+            __implements__ = (IMachin,)
+    '''
+    )
+    with pytest.warns(DeprecationWarning):
+        linker.visit_classdef(cls)