Fix WarningsRecorder.pop() returning the last match for unrelated categories

AUTHORS

@@ -11,6 +11,7 @@ ace2016
 Adam Johnson
 Adam Stewart
 Adam Uhlir
+Aditya Kumar
 Aditya Tripuraneni
 Ahn Ki-Wook
 Akhilesh Ramakrishnan

changelog/15097.bugfix.rst

@@ -0,0 +1 @@
+:meth:`WarningsRecorder.pop() <pytest.WarningsRecorder.pop>` now returns the first matching warning again when the recorded warnings have unrelated categories, instead of the last one.

src/_pytest/recwarn.py

@@ -213,17 +213,17 @@ def pop(self, cls: type[Warning] = Warning) -> warnings.WarningMessage:
         but not an instance of a child class of any other match.
         Raises ``AssertionError`` if there is no match.
         """
-        best_idx: int | None = None
-        for i, w in enumerate(self._list):
-            if w.category == cls:
-                return self._list.pop(i)  # exact match, stop looking
-            if issubclass(w.category, cls) and (
-                best_idx is None
-                or not issubclass(w.category, self._list[best_idx].category)
+        matches = [
+            (i, w.category)
+            for i, w in enumerate(self._list)
+            if issubclass(w.category, cls)
+        ]
+        for i, category in matches:
+            if not any(
+                other is not category and issubclass(category, other)
+                for _, other in matches
             ):
-                best_idx = i
-        if best_idx is not None:
-            return self._list.pop(best_idx)
+                return self._list.pop(i)
         __tracebackhide__ = True
         raise AssertionError(f"{cls!r} not found in warning list")
 

testing/test_recwarn.py

@@ -82,6 +82,25 @@ def test_pop_finds_best_inexact_match(self):
         _warn = record.pop(self.ParentWarning)
         assert _warn.category is self.ChildWarning
 
+    def test_pop_finds_first_of_unrelated_matches(self):
+        with pytest.warns(Warning) as record:
+            self.raise_warnings_from_list(
+                [self.ChildWarning, UserWarning, DeprecationWarning]
+            )
+
+        assert record.pop().category is self.ChildWarning
+        assert record.pop().category is UserWarning
+        assert record.pop().category is DeprecationWarning
+
+    def test_pop_skips_child_of_later_match(self):
+        with pytest.warns(Warning) as record:
+            self.raise_warnings_from_list(
+                [self.ChildWarning, UserWarning, self.ParentWarning]
+            )
+
+        _warn = record.pop()
+        assert _warn.category is UserWarning
+
 
 class TestWarningsRecorderChecker:
     def test_recording(self) -> None: