Refactor regular expression to avoid expensive backtracking on contri…

…ved entry points. Fixes #361. Credit to Tim Peters. Reduces cost from almost 2 seconds to ~100 µs on my workstation as reported by entrypoint_regexp_perf.
python · Jan 17, 2022 · aa4f879 · aa4f879
1 parent 4dbecdb
commit aa4f879
Showing 1 changed file with 2 additions and 2 deletions.
diff --git a/importlib_metadata/__init__.py b/importlib_metadata/__init__.py
@@ -161,8 +161,8 @@ class EntryPoint(DeprecatedTuple):
 
     pattern = re.compile(
         r'(?P<module>[\w.]+)\s*'
-        r'(:\s*(?P<attr>[\w.]+))?\s*'
-        r'(?P<extras>\[.*\])?\s*$'
+        r'(:\s*(?P<attr>[\w.]+)\s*)?'
+        r'((?P<extras>\[.*\])\s*)?$'
     )
     """
     A regular expression describing the syntax for an entry point,