Point the missing-argument warning at the code making the hook call

changelog/727.bugfix.rst

@@ -0,0 +1 @@
+Fix the warning for hookspec arguments missing from a hook call being attributed to pluggy's own frame instead of to the code making the call. This affected ``HookCaller.__call__``, ``call_historic`` and ``call_extra``.

src/pluggy/_hooks.py

@@ -520,7 +520,10 @@ def _verify_all_args_are_provided(self, kwargs: Mapping[str, object]) -> None:
                     warnings.warn(
                         f"Argument(s) {notincall} which are declared in the hookspec "
                         "cannot be found in this hook call",
-                        stacklevel=2,
+                        # 3, not 2: the warning is raised in this helper, which
+                        # is called by __call__/call_historic/call_extra, which
+                        # are called by the code making the hook call.
+                        stacklevel=3,
                     )
                     break
 

testing/test_details.py

@@ -180,6 +180,37 @@ def herstory(self, arg1, arg2):
         pm.hook.herstory.call_historic(kwargs={})
 
 
+def test_not_all_arguments_warning_points_at_the_caller(pm: PluginManager) -> None:
+    """The warning must be attributed to the code making the hook call.
+
+    It is raised inside a helper two frames below the caller, so a stacklevel
+    that is off by one blames pluggy's own frame instead.
+    """
+
+    class Spec:
+        @hookspec
+        def hello(self, arg1, arg2):
+            pass  # pragma: no cover
+
+        @hookspec(historic=True)
+        def herstory(self, arg1, arg2):
+            pass  # pragma: no cover
+
+    pm.add_hookspecs(Spec)
+
+    with pytest.warns(UserWarning) as record:
+        pm.hook.hello(arg1=1)
+    assert record[0].filename == __file__
+
+    with pytest.warns(UserWarning) as record:
+        pm.hook.hello.call_extra([], kwargs={})
+    assert record[0].filename == __file__
+
+    with pytest.warns(UserWarning) as record:
+        pm.hook.herstory.call_historic(kwargs={})
+    assert record[0].filename == __file__
+
+
 def test_repr() -> None:
     class Plugin:
         @hookimpl