Escape newlines in LogfmtRenderer

CHANGELOG.md

@@ -15,6 +15,9 @@ You can find our backwards-compatibility policy [here](https://github.com/hynek/
 
 ## [Unreleased](https://github.com/hynek/structlog/compare/24.1.0...HEAD)
 
+### Changed
+
+- `structlog.processors.LogfmtRenderer` now escapes newlines
 
 ## [24.1.0](https://github.com/hynek/structlog/compare/23.3.0...24.1.0) - 2024-01-08
 

src/structlog/processors.py

@@ -170,7 +170,7 @@ def __call__(
                     continue
                 value = "true" if value else "false"
 
-            value = f"{value}".replace('"', '\\"')
+            value = f"{value}".replace('"', '\\"').replace("\n", "\\n")
 
             if " " in value or "=" in value:
                 value = f'"{value}"'

tests/test_processors.py

@@ -290,6 +290,14 @@ def test_invalid_key(self):
         with pytest.raises(ValueError, match='Invalid key: "invalid key"'):
             LogfmtRenderer()(None, None, event_dict)
 
+    def test_newline_in_value(self):
+        """
+        Newlines in values should be escaped
+        """
+        event_dict = {"with_newline": "some\nvalue"}
+        rv = LogfmtRenderer()(None, None, event_dict)
+        assert r"with_newline=some\nvalue" == rv
+
 
 class TestJSONRenderer:
     def test_renders_json(self, event_dict):