stdlib.render_to_log_kwargs: fix handling of special kwargs (#427)

* stdlib.render_to_log_kwargs: fix handling of special kwargs

Co-authored-by: Serhii Tereshchenko <serg.partizan@gmail.com>

* Add second PR#

Co-authored-by: Serhii Tereshchenko <serg.partizan@gmail.com>

CHANGELOG.md

@@ -73,6 +73,10 @@ So please make sure to **always** properly configure your applications.
   [#392](https://github.com/hynek/structlog/pull/392)
 - Monkeypatched `sys.stdout`s are now handled more gracefully by `ConsoleRenderer` (that's used by default).
   [#404](https://github.com/hynek/structlog/pull/404)
+- `structlog.stdlib.render_to_log_kwargs()` now correctly handles the presence of `exc_info`, `stack_info`, and `stackLevel` in the event dictionary.
+  They are transformed into proper keyword arguments instead of putting them into the `extra` dictionary.
+  [#424](https://github.com/hynek/structlog/issues/424),
+  [#427](https://github.com/hynek/structlog/issues/427)
 
 
 ## [21.5.0](https://github.com/hynek/structlog/compare/21.4.0...21.5.0) - 2021-12-16

conftest.py

@@ -41,8 +41,8 @@ def _sio():
     return StringIO()
 
 
-@pytest.fixture
-def event_dict():
+@pytest.fixture(name="event_dict")
+def _event_dict():
     """
     An example event dictionary with multiple value types w/o the event itself.
     """

src/structlog/stdlib.py

@@ -738,8 +738,18 @@ def render_to_log_kwargs(
     This allows you to defer formatting to `logging`.
 
     .. versionadded:: 17.1.0
+    .. versionchanged:: 22.1.0 ``exc_info``, ``stack_info``, and ``stackLevel``
+       are passed as proper kwargs and not put into ``extra``.
     """
-    return {"msg": event_dict.pop("event"), "extra": event_dict}
+    return {
+        "msg": event_dict.pop("event"),
+        "extra": event_dict,
+        **{
+            kw: event_dict.pop(kw)
+            for kw in ("exc_info", "stack_info", "stackLevel")
+            if kw in event_dict
+        },
+    }
 
 
 class ProcessorFormatter(logging.Formatter):

tests/test_stdlib.py

@@ -624,6 +624,34 @@ def test_add_extra_event_dict(self, event_dict):
 
         assert {"msg": "message", "extra": event_dict} == d
 
+    def test_handles_special_kw(self, event_dict):
+        """
+        "exc_info", "stack_info", and "stackLevel" aren't passed as extras.
+
+        Cf. https://github.com/hynek/structlog/issues/424
+        """
+        del event_dict["a"]  # needs a repr
+        event_dict["event"] = "message"
+
+        event_dict["exc_info"] = True
+        event_dict["stack_info"] = False
+        event_dict["stackLevel"] = 1
+
+        d = render_to_log_kwargs(None, None, event_dict)
+
+        assert {
+            "msg": "message",
+            "exc_info": True,
+            "stack_info": False,
+            "stackLevel": 1,
+            "extra": {
+                "b": [3, 4],
+                "x": 7,
+                "y": "test",
+                "z": (1, 2),
+            },
+        } == d
+
 
 @pytest.fixture(name="configure_for_processor_formatter")
 def _configure_for_processor_formatter():