remove duplicate warnings while running autoupdate

pre_commit/commands/migrate_config.py

@@ -3,7 +3,6 @@ import textwrap
 
 import yaml
 
-from pre_commit.clientlib import load_config
 from pre_commit.util import yaml_load
 
 
@@ -40,9 +39,6 @@ def _migrate_sha_to_rev(contents: str) -> str:
 
 
 def migrate_config(config_file: str, quiet: bool = False) -> int:
-    # ensure that the configuration is a valid pre-commit configuration
-    load_config(config_file)
-
     with open(config_file) as f:
         orig_contents = contents = f.read()
 

tests/commands/migrate_config_test.py

@@ -1,7 +1,4 @@
-import pytest
-
 import pre_commit.constants as C
-from pre_commit.clientlib import InvalidConfigError
 from pre_commit.commands.migrate_config import migrate_config
 
 
@@ -130,13 +127,3 @@ def test_migrate_config_sha_to_rev(tmpdir):
         '    rev: v1.2.0\n'
         '    hooks: []\n'
     )
-
-
-@pytest.mark.parametrize('contents', ('', '\n'))
-def test_migrate_config_invalid_configuration(tmpdir, contents):
-    cfg = tmpdir.join(C.CONFIG_FILE)
-    cfg.write(contents)
-    with tmpdir.as_cwd(), pytest.raises(InvalidConfigError):
-        migrate_config(C.CONFIG_FILE)
-    # even though the config is invalid, this should be a noop
-    assert cfg.read() == contents