Don't raise MissingParameter on keyword-only params when **kwargs is present.

rchen152 · rchen152 · commit 69a48e45dad0 · 2024-01-23T14:11:26.000-08:00
PiperOrigin-RevId: 600902503
diff --git a/pytype/abstract/_function_base.py b/pytype/abstract/_function_base.py
@@ -525,17 +525,16 @@ def _map_args(self, node, args):
       raise function.WrongKeywordArgs(sig, args, self.ctx, posonly_kws)
     callargs.update(positional)
     callargs.update(kws)
-    for key, kwonly in self.get_nondefault_params():
+    for key, kwonly in itertools.chain(
+        self.get_nondefault_params(),
+        ((key, True) for key in sig.kwonly_params)):
       if key not in callargs:
         if args.starstarargs or (args.starargs and not kwonly):
           # We assume that because we have *args or **kwargs, we can use these
           # to fill in any parameters we might be missing.
           callargs[key] = self.ctx.new_unsolvable(node)
         else:
           raise function.MissingParameter(sig, args, self.ctx, key)
-    for key in sig.kwonly_params:
-      if key not in callargs:
-        raise function.MissingParameter(sig, args, self.ctx, key)
     if sig.varargs_name:
       varargs_name = sig.varargs_name
       extraneous = posargs[self.argcount(node):]
diff --git a/pytype/tests/test_dataclasses.py b/pytype/tests/test_dataclasses.py
@@ -781,6 +781,18 @@ class C:
         def __init__(self, *, x: int = ..., y: str) -> None: ...
     """)
 
+  @test_utils.skipBeforePy((3, 10), "KW_ONLY is new in 3.10")
+  def test_kwonly_and_kwargs(self):
+    self.Check("""
+      import dataclasses
+      @dataclasses.dataclass
+      class C:
+        _: dataclasses.KW_ONLY
+        x: int
+      def f(**kwargs):
+        return C(**kwargs)
+    """)
+
   def test_star_import(self):
     with self.DepTree([("foo.pyi", """
       import dataclasses
