Display "exception" logs as level "error" (#586)

* Display "exception" logs as level "error"

* Update CHANGELOG.md

* Update src/structlog/_log_levels.py

---------

Co-authored-by: Hynek Schlawack <hs@ox.cx>

CHANGELOG.md

@@ -20,6 +20,10 @@ You can find our backwards-compatibility policy [here](https://github.com/hynek/
 - The lazy logger proxy returned by `structlog.get_logger()` now returns its initial values when asked for context.
   When asked for context before binding for the first time, it returned an empty dictionary in 23.3.0.
 
+- The displayed level name when using `structlog.stdlib.BoundLogger.exception()` is `"error"` instead of `"exception"`.
+  Fixes regression in 23.3.0.
+  [#584](https://github.com/hynek/structlog/issues/584)
+
 - Don't ignore the `width` argument of `RichTracebackFormatter`.
   [#587](https://github.com/hynek/structlog/issues/587)
 

src/structlog/_log_levels.py

@@ -60,10 +60,15 @@ def add_log_level(
     .. versionchanged:: 20.2.0
        Importable from `structlog.processors` (additionally to
        `structlog.stdlib`).
+    .. versionchanged:: 24.1.0
+       Added mapping from "exception" to "error"
     """
     if method_name == "warn":
         # The stdlib has an alias
         method_name = "warning"
+    elif method_name == "exception":
+        # exception("") method is the same as error("", exc_info=True)
+        method_name = "error"
 
     event_dict["level"] = method_name
 

tests/test_stdlib.py

@@ -488,13 +488,16 @@ def test_log_level_added(self):
 
         assert "error" == event_dict["level"]
 
-    def test_log_level_alias_normalized(self):
+    @pytest.mark.parametrize(
+        ("alias", "normalized"), [("warn", "warning"), ("exception", "error")]
+    )
+    def test_log_level_alias_normalized(self, alias, normalized):
         """
         The normalized name of the log level is added to the event dict.
         """
-        event_dict = add_log_level(None, "warn", {})
+        event_dict = add_log_level(None, alias, {})
 
-        assert "warning" == event_dict["level"]
+        assert normalized == event_dict["level"]
 
 
 @pytest.fixture(name="make_log_record")