From ce25b652b91966b0dfb528299f8f1f84a3893192 Mon Sep 17 00:00:00 2001
From: Anthony Sottile <asottile@umich.edu>
Date: Sun, 2 Sep 2018 18:54:34 -0700
Subject: [PATCH] Exempt `language: fail` hooks from check-hooks-apply

---
 pre_commit/meta_hooks/check_hooks_apply.py |  2 +-
 tests/meta_hooks/check_hooks_apply_test.py | 31 +++++++++++++++++++++-
 2 files changed, 31 insertions(+), 2 deletions(-)

diff --git a/pre_commit/meta_hooks/check_hooks_apply.py b/pre_commit/meta_hooks/check_hooks_apply.py
index 23420f46..4c4719c8 100644
--- a/pre_commit/meta_hooks/check_hooks_apply.py
+++ b/pre_commit/meta_hooks/check_hooks_apply.py
@@ -15,7 +15,7 @@ def check_all_hooks_match_files(config_file):
 
     for repo in repositories(load_config(config_file), Store()):
         for hook_id, hook in repo.hooks:
-            if hook['always_run']:
+            if hook['always_run'] or hook['language'] == 'fail':
                 continue
             include, exclude = hook['files'], hook['exclude']
             filtered = _filter_by_include_exclude(files, include, exclude)
diff --git a/tests/meta_hooks/check_hooks_apply_test.py b/tests/meta_hooks/check_hooks_apply_test.py
index e6a7b133..c75b036a 100644
--- a/tests/meta_hooks/check_hooks_apply_test.py
+++ b/tests/meta_hooks/check_hooks_apply_test.py
@@ -106,7 +106,7 @@ def test_hook_types_excludes_everything(
     assert 'check-useless-excludes does not apply to this repository' in out
 
 
-def test_valid_includes(capsys, tempdir_factory, mock_store_dir):
+def test_valid_always_run(capsys, tempdir_factory, mock_store_dir):
     config = {
         'repos': [
             {
@@ -131,3 +131,32 @@ def test_valid_includes(capsys, tempdir_factory, mock_store_dir):
 
     out, _ = capsys.readouterr()
     assert out == ''
+
+
+def test_valid_language_fail(capsys, tempdir_factory, mock_store_dir):
+    config = {
+        'repos': [
+            {
+                'repo': 'local',
+                'hooks': [
+                    # Should not be reported as an error due to language: fail
+                    {
+                        'id': 'changelogs-rst',
+                        'name': 'changelogs must be rst',
+                        'entry': 'changelog filenames must end in .rst',
+                        'language': 'fail',
+                        'files': r'changelog/.*(?<!\.rst)$',
+                    },
+                ],
+            },
+        ],
+    }
+
+    repo = git_dir(tempdir_factory)
+    add_config_to_repo(repo, config)
+
+    with cwd(repo):
+        assert check_hooks_apply.main(()) == 0
+
+    out, _ = capsys.readouterr()
+    assert out == ''