subscripts work again

charithmadhuranga · Jan 12, 2024 · bcd59a8 · bcd59a8
1 parent 88151eb
commit bcd59a8
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Showing 2 changed files with 23 additions and 1 deletion.
diff --git a/src/twisted/logger/_format.py b/src/twisted/logger/_format.py
@@ -201,6 +201,12 @@ def __init__(self, wrapped: object) -> None:
     def __getattr__(self, name: str) -> object:
         return keycall(name, self._wrapped.__getattribute__)
 
+    def __getitem__(self, name: str) -> object:
+        # The sub-object may not be indexable, but if it isn't, that's the
+        # caller's problem.
+        value = self._wrapped[name]  # type:ignore[index]
+        return PotentialCallWrapper(value)
+
     def __format__(self, format_spec: str) -> str:
         return self._wrapped.__format__(format_spec)
 

diff --git a/src/twisted/logger/test/test_format.py b/src/twisted/logger/test/test_format.py
@@ -5,7 +5,7 @@
 Test cases for L{twisted.logger._format}.
 """
 
-from typing import AnyStr, Optional, cast
+from typing import AnyStr, Dict, Optional, cast
 
 try:
     from time import tzset
@@ -95,6 +95,22 @@ def where(self) -> str:
             "hello world", self.format("hello {what.where()}", what=World())
         )
 
+    def test_formatAttributeSubscript(self) -> None:
+        """
+        L{formatEvent} will format subscripts of attributes per PEP 3101.
+        """
+
+        class Example(object):
+            config: Dict[str, str] = dict(foo="bar", baz="qux")
+
+        self.assertEqual(
+            "bar qux",
+            self.format(
+                "{example.config[foo]} {example.config[baz]}",
+                example=Example(),
+            ),
+        )
+
     def test_formatEventNoFormat(self) -> None:
         """
         Formatting an event with no format.