[py] warn once per record for undeclared BiDi properties, not once per key

Author: titusfortner

py/selenium/webdriver/common/_bidi/serialization.py

@@ -274,11 +274,14 @@ def from_json(cls, payload: dict) -> Any:
                 continue
             kwargs[f.name] = _read_field(cls, f.name, w, payload)
         undeclared = [k for k in payload if k not in known]
-        for key in undeclared:
-            # A property the type does not declare is tolerated for forward-compatibility
-            # (ADR decision 2.3): warned, and kept only on an extensible (re-sendable) type
-            # so a caller can echo it back on the wire — otherwise dropped.
-            _tolerate(f"{cls.__name__}: undeclared property {key!r} ({'kept' if cls._EXTENSIBLE else 'dropped'})")
+        if undeclared:
+            # Properties the type does not declare are tolerated for forward-compatibility
+            # (ADR decision 2.3): warned once for the whole record — not once per key, so a
+            # verbose payload cannot flood the log — and kept only on an extensible
+            # (re-sendable) type so a caller can echo them back on the wire, else dropped.
+            noun = "property" if len(undeclared) == 1 else "properties"
+            names = ", ".join(repr(k) for k in undeclared)
+            _tolerate(f"{cls.__name__}: undeclared {noun} {names} ({'kept' if cls._EXTENSIBLE else 'dropped'})")
         if cls._EXTENSIBLE:
             kwargs["extensions"] = {k: payload[k] for k in undeclared}
         return cls(**kwargs)

py/test/unit/selenium/webdriver/common/bidi_serialization_tests.py

@@ -403,6 +403,16 @@ def test_strict_inbound_escalates_an_undeclared_property_to_an_error():
         Point.from_json({"x": 1, "y": 2, "z": 3})
 
 
+def test_many_undeclared_properties_warn_once_for_the_record_not_once_per_key(caplog):
+    with caplog.at_level(logging.WARNING):
+        Point.from_json({"x": 1, "y": 2, "a": 1, "b": 2, "c": 3})
+    undeclared_warnings = [r for r in caplog.records if "undeclared" in r.getMessage()]
+    assert len(undeclared_warnings) == 1
+    assert "a" in caplog.text
+    assert "b" in caplog.text
+    assert "c" in caplog.text
+
+
 # --- union dispatch: inbound ---