Added support for deprecated method alias

2 files changed, 34 insertions, 5 deletions

diff --git a/pylint/checkers/deprecated.py b/pylint/checkers/deprecated.py
index ce1563a3c..7f1089843 100644
--- a/pylint/checkers/deprecated.py
+++ b/pylint/checkers/deprecated.py
@@ -197,15 +197,19 @@ class DeprecatedMixin:
             # Not interested in other nodes.
             return
 
-        qname = inferred.qname()
-        if any(name in self.deprecated_methods() for name in (qname, func_name)):
+        if hasattr(inferred.parent, "qname") and inferred.parent.qname():
+            # Handling the situation when deprecated function is
+            # alias to existing function.
+            qnames = {inferred.qname(), f"{inferred.parent.qname()}.{func_name}"}
+        else:
+            qnames = {inferred.qname(), func_name}
+        if any(name in self.deprecated_methods() for name in qnames):
             self.add_message("deprecated-method", node=node, args=(func_name,))
             return
         num_of_args = len(node.args)
         kwargs = {kw.arg for kw in node.keywords} if node.keywords else {}
-        for position, arg_name in chain(
-            self.deprecated_arguments(func_name), self.deprecated_arguments(qname)
-        ):
+        deprecated_arguments = (self.deprecated_arguments(qn) for qn in qnames)
+        for position, arg_name in chain(*deprecated_arguments):
             if arg_name in kwargs:
                 # function was called with deprecated argument as keyword argument
                 self.add_message(
diff --git a/tests/checkers/unittest_deprecated.py b/tests/checkers/unittest_deprecated.py
index 2da2bce17..5a1ec1c2c 100644
--- a/tests/checkers/unittest_deprecated.py
+++ b/tests/checkers/unittest_deprecated.py
@@ -91,6 +91,31 @@ class TestDeprecatedChecker(CheckerTestCase):
         ):
             self.checker.visit_call(node)
 
+    def test_deprecated_method_alias(self):
+        # Tests detecting deprecated method defined as alias
+        # to existing method
+        node = astroid.extract_node(
+            """
+        class Deprecated:
+            def _deprecated_method():
+                pass
+
+            deprecated_method = _deprecated_method
+
+        d = Deprecated()
+        d.deprecated_method()
+        """
+        )
+        with self.assertAddsMessages(
+            Message(
+                msg_id="deprecated-method",
+                args=("deprecated_method",),
+                node=node,
+                confidence=UNDEFINED,
+            )
+        ):
+            self.checker.visit_call(node)
+
     def test_no_message(self):
         # Tests not raising error when no deprecated functions/methods are present.
         node = astroid.extract_node(