Only configure logging inside the context

pre_commit/logging_handler.py

@@ -1,5 +1,6 @@
 from __future__ import unicode_literals
 
+import contextlib
 import logging
 
 from pre_commit import color
@@ -34,6 +35,12 @@ class LoggingHandler(logging.Handler):
         )
 
 
-def add_logging_handler(*args, **kwargs):
-    logger.addHandler(LoggingHandler(*args, **kwargs))
+@contextlib.contextmanager
+def logging_handler(*args, **kwargs):
+    handler = LoggingHandler(*args, **kwargs)
+    logger.addHandler(handler)
     logger.setLevel(logging.INFO)
+    try:
+        yield
+    finally:
+        logger.removeHandler(handler)

pre_commit/main.py

@@ -20,7 +20,7 @@ from pre_commit.commands.sample_config import sample_config
 from pre_commit.commands.try_repo import try_repo
 from pre_commit.error_handler import error_handler
 from pre_commit.error_handler import FatalError
-from pre_commit.logging_handler import add_logging_handler
+from pre_commit.logging_handler import logging_handler
 from pre_commit.store import Store
 from pre_commit.util import CalledProcessError
 
@@ -248,9 +248,7 @@ def main(argv=None):
     elif args.command == 'help':
         parser.parse_args(['--help'])
 
-    with error_handler():
-        add_logging_handler(args.color)
-
+    with error_handler(), logging_handler(args.color):
         _adjust_args_and_chdir(args)
 
         store = Store()