Make RequestsCookieJar.popitem() work

src/requests/cookies.py

@@ -299,6 +299,23 @@ def items(self) -> list[tuple[str, str | None]]:  # type: ignore[override]
         """
         return list(self.iteritems())
 
+    def popitem(self) -> tuple[str, str | None]:
+        """Dict-like popitem() that removes and returns a (name, value) pair,
+        or raises KeyError if the jar is empty.
+
+        The inherited ``MutableMapping.popitem`` does not work here because
+        ``__iter__`` yields ``Cookie`` objects rather than names.
+        """
+        try:
+            cookie = next(iter(self))
+        except StopIteration:
+            raise KeyError("popitem(): cookie jar is empty") from None
+        # Remove the exact cookie the iterator selected. Deleting by name alone
+        # (``del self[name]``) would drop every cookie sharing that name across
+        # other domains/paths, not just the one returned here.
+        self.clear(cookie.domain, cookie.path, cookie.name)
+        return cookie.name, cookie.value
+
     def list_domains(self) -> list[str]:
         """Utility method to list all the domains in the jar."""
         domains: list[str] = []

tests/test_requests.py

@@ -1313,6 +1313,40 @@ def test_cookie_parameters(self):
         assert cookie.domain == domain
         assert cookie._rest["HttpOnly"] == rest["HttpOnly"]
 
+    def test_cookie_popitem(self):
+        jar = requests.cookies.RequestsCookieJar()
+        jar.set("some_cookie", "some_value")
+        jar.set("some_cookie1", "some_value1")
+
+        items = dict(jar.items())
+
+        name, value = jar.popitem()
+        assert (name, value) in items.items()
+        assert name not in jar
+        assert len(jar) == 1
+
+        jar.popitem()
+        assert len(jar) == 0
+
+        with pytest.raises(KeyError):
+            jar.popitem()
+
+    def test_cookie_popitem_removes_only_the_selected_cookie(self):
+        # Two cookies share a name but live on different domains. popitem() must
+        # remove exactly the one it returns, not every cookie with that name.
+        jar = requests.cookies.RequestsCookieJar()
+        jar.set("dup", "value-a", domain="a.example.com", path="/")
+        jar.set("dup", "value-b", domain="b.example.com", path="/")
+        assert len(jar) == 2
+
+        name, value = jar.popitem()
+        assert name == "dup"
+        assert len(jar) == 1
+
+        remaining = next(iter(jar))
+        assert remaining.name == "dup"
+        assert {value, remaining.value} == {"value-a", "value-b"}
+
     def test_cookie_as_dict_keeps_len(self):
         key = "some_cookie"
         value = "some_value"