From 0273db7fb4b77c882e40cd766c61a56a0cb2b8e2 Mon Sep 17 00:00:00 2001
From: "github-actions[bot]"
 <41898282+github-actions[bot]@users.noreply.github.com>
Date: Sun, 29 Oct 2023 19:45:28 +0000
Subject: [PATCH] Fix false positive for ``unnecessary-lambda``. (#9149)
 (#9200)
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This simplifies the check for the call having kwargs but not the lambda.

(cherry picked from commit 2289c7156638dc64c49d149e0bdd23f50fc471a4)

Co-authored-by: Clément Schreiner <clement@mux.me>
---
 doc/whatsnew/fragments/9148.false_positive       |  3 +++
 pylint/checkers/base/basic_checker.py            | 16 +++-------------
 .../u/unnecessary/unnecessary_lambda.py          |  4 ++++
 3 files changed, 10 insertions(+), 13 deletions(-)
 create mode 100644 doc/whatsnew/fragments/9148.false_positive

diff --git a/doc/whatsnew/fragments/9148.false_positive b/doc/whatsnew/fragments/9148.false_positive
new file mode 100644
index 0000000000..647deb103e
--- /dev/null
+++ b/doc/whatsnew/fragments/9148.false_positive
@@ -0,0 +1,3 @@
+Fixed false positive for ``unnecessary-lambda`` when the call has keyword arguments but not the lambda.
+
+Closes #9148
diff --git a/pylint/checkers/base/basic_checker.py b/pylint/checkers/base/basic_checker.py
index 3505ee7082..8aaa274d65 100644
--- a/pylint/checkers/base/basic_checker.py
+++ b/pylint/checkers/base/basic_checker.py
@@ -519,7 +519,6 @@ def _has_variadic_argument(
         )
 
     @utils.only_required_for_messages("unnecessary-lambda")
-    # pylint: disable-next=too-many-return-statements
     def visit_lambda(self, node: nodes.Lambda) -> None:
         """Check whether the lambda is suspicious."""
         # if the body of the lambda is a call expression with the same
@@ -544,12 +543,13 @@ def visit_lambda(self, node: nodes.Lambda) -> None:
             # return something else (but we don't check that, yet).
             return
 
-        call_site = astroid.arguments.CallSite.from_call(call)
         ordinary_args = list(node.args.args)
         new_call_args = list(self._filter_vararg(node, call.args))
         if node.args.kwarg:
-            if self._has_variadic_argument(call.kwargs, node.args.kwarg):
+            if self._has_variadic_argument(call.keywords, node.args.kwarg):
                 return
+        elif call.keywords:
+            return
 
         if node.args.vararg:
             if self._has_variadic_argument(call.starargs, node.args.vararg):
@@ -557,16 +557,6 @@ def visit_lambda(self, node: nodes.Lambda) -> None:
         elif call.starargs:
             return
 
-        if call.keywords:
-            # Look for additional keyword arguments that are not part
-            # of the lambda's signature
-            lambda_kwargs = {keyword.name for keyword in node.args.defaults}
-            if len(lambda_kwargs) != len(call_site.keyword_arguments):
-                # Different lengths, so probably not identical
-                return
-            if set(call_site.keyword_arguments).difference(lambda_kwargs):
-                return
-
         # The "ordinary" arguments must be in a correspondence such that:
         # ordinary_args[i].name == call.args[i].name.
         if len(ordinary_args) != len(new_call_args):
diff --git a/tests/functional/u/unnecessary/unnecessary_lambda.py b/tests/functional/u/unnecessary/unnecessary_lambda.py
index 82571a4444..85c30fef28 100644
--- a/tests/functional/u/unnecessary/unnecessary_lambda.py
+++ b/tests/functional/u/unnecessary/unnecessary_lambda.py
@@ -52,6 +52,10 @@
 _ = lambda: _ANYARGS(*[3], **{'three': 3})
 _ = lambda: _ANYARGS(func=42)
 
+# pylint: disable=missing-function-docstring
+def f(d):
+    print(lambda x: str(x, **d))
+
 # Don't warn about this.
 _ = lambda: code().analysis()