Fix several ResourceWarning: unclosed file

pre_commit/commands/autoupdate.py

@@ -72,7 +72,8 @@ REV_LINE_FMT = '{}rev:{}{}{}'
 
 
 def _write_new_config_file(path, output):
-    original_contents = open(path).read()
+    with open(path) as f:
+        original_contents = f.read()
     output = remove_defaults(output, CONFIG_SCHEMA)
     new_contents = ordered_dump(output, **C.YAML_DUMP_KWARGS)
 

pre_commit/commands/install_uninstall.py

@@ -38,7 +38,8 @@ def _hook_paths(git_root, hook_type):
 def is_our_script(filename):
     if not os.path.exists(filename):
         return False
-    contents = io.open(filename).read()
+    with io.open(filename) as f:
+        contents = f.read()
     return any(h in contents for h in (CURRENT_HASH,) + PRIOR_HASHES)
 
 

pre_commit/git.py

@@ -70,7 +70,8 @@ def get_conflicted_files():
     logger.info('Checking merge-conflict files only.')
     # Need to get the conflicted files from the MERGE_MSG because they could
     # have resolved the conflict by choosing one side or the other
-    merge_msg = open(os.path.join(get_git_dir('.'), 'MERGE_MSG'), 'rb').read()
+    with open(os.path.join(get_git_dir('.'), 'MERGE_MSG'), 'rb') as f:
+        merge_msg = f.read()
     merge_conflict_filenames = parse_merge_msg_for_conflicts(merge_msg)
 
     # This will get the rest of the changes made after the merge.

pre_commit/repository.py

@@ -43,7 +43,8 @@ def _read_state(prefix, venv):
     if not os.path.exists(filename):
         return None
     else:
-        return json.loads(io.open(filename).read())
+        with io.open(filename) as f:
+            return json.loads(f.read())
 
 
 def _write_state(prefix, venv, state):