config: Implement for ignore-from-file option

Closes https://github.com/adrienverge/yamllint/issues/360
Co-authored-by: Adrien Vergé <@adrienverge>

docs/configuration.rst

@@ -190,6 +190,20 @@ Here is a more complex example:
        *.ignore-trailing-spaces.yaml
        ascii-art/*
 
+You can also use the ``.gitignore`` file (or any list of files) through:
+
+.. code-block:: yaml
+
+ ignore-from-file: .gitignore
+
+or:
+
+.. code-block:: yaml
+
+ ignore-from-file: [.gitignore, .yamlignore]
+
+.. note:: However, this is mutually exclusive with the ``ignore`` key.
+
 Setting the locale
 ------------------
 

tests/test_config.py

@@ -22,6 +22,7 @@ import unittest
 
 from tests.common import build_temp_workspace
 
+from yamllint.config import YamlLintConfigError
 from yamllint import cli
 from yamllint import config
 
@@ -429,10 +430,10 @@ class ExtendedLibraryConfigTestCase(unittest.TestCase):
         self.assertEqual(new.rules['empty-lines']['max-end'], 0)
 
 
-class IgnorePathConfigTestCase(unittest.TestCase):
+class IgnoreConfigTestCase(unittest.TestCase):
     @classmethod
     def setUpClass(cls):
-        super(IgnorePathConfigTestCase, cls).setUpClass()
+        super().setUpClass()
 
         bad_yaml = ('---\n'
                     '- key: val1\n'
@@ -452,22 +453,6 @@ class IgnorePathConfigTestCase(unittest.TestCase):
             's/s/ign-trail/file.yaml': bad_yaml,
             's/s/ign-trail/s/s/file.yaml': bad_yaml,
             's/s/ign-trail/s/s/file2.lint-me-anyway.yaml': bad_yaml,
-
-            '.yamllint': 'ignore: |\n'
-                         '  *.dont-lint-me.yaml\n'
-                         '  /bin/\n'
-                         '  !/bin/*.lint-me-anyway.yaml\n'
-                         '\n'
-                         'extends: default\n'
-                         '\n'
-                         'rules:\n'
-                         '  key-duplicates:\n'
-                         '    ignore: |\n'
-                         '      /ign-dup\n'
-                         '  trailing-spaces:\n'
-                         '    ignore: |\n'
-                         '      ign-trail\n'
-                         '      !*.lint-me-anyway.yaml\n',
         })
 
         cls.backup_wd = os.getcwd()
@@ -475,13 +460,101 @@ class IgnorePathConfigTestCase(unittest.TestCase):
 
     @classmethod
     def tearDownClass(cls):
-        super(IgnorePathConfigTestCase, cls).tearDownClass()
+        super().tearDownClass()
 
         os.chdir(cls.backup_wd)
 
         shutil.rmtree(cls.wd)
 
-    def test_run_with_ignored_path(self):
+    def test_mutually_exclusive_ignore_keys(self):
+        self.assertRaises(
+            YamlLintConfigError,
+            config.YamlLintConfig, 'extends: default\n'
+                                   'ignore-from-file: .gitignore\n'
+                                   'ignore: |\n'
+                                   '  *.dont-lint-me.yaml\n'
+                                   '  /bin/\n')
+
+    def test_ignore_from_file_not_exist(self):
+        self.assertRaises(
+            FileNotFoundError,
+            config.YamlLintConfig, 'extends: default\n'
+                                   'ignore-from-file: not_found_file\n')
+
+    def test_ignore_from_file_incorrect_type(self):
+        self.assertRaises(
+            YamlLintConfigError,
+            config.YamlLintConfig, 'extends: default\n'
+                                   'ignore-from-file: 0\n')
+        self.assertRaises(
+            YamlLintConfigError,
+            config.YamlLintConfig, 'extends: default\n'
+                                   'ignore-from-file: [0]\n')
+
+    def test_no_ignore(self):
+        sys.stdout = StringIO()
+        with self.assertRaises(SystemExit):
+            cli.run(('-f', 'parsable', '.'))
+
+        out = sys.stdout.getvalue()
+        out = '\n'.join(sorted(out.splitlines()))
+
+        keydup = '[error] duplication of key "key" in mapping (key-duplicates)'
+        trailing = '[error] trailing spaces (trailing-spaces)'
+        hyphen = '[error] too many spaces after hyphen (hyphens)'
+
+        self.assertEqual(out, '\n'.join((
+            './bin/file.lint-me-anyway.yaml:3:3: ' + keydup,
+            './bin/file.lint-me-anyway.yaml:4:17: ' + trailing,
+            './bin/file.lint-me-anyway.yaml:5:5: ' + hyphen,
+            './bin/file.yaml:3:3: ' + keydup,
+            './bin/file.yaml:4:17: ' + trailing,
+            './bin/file.yaml:5:5: ' + hyphen,
+            './file-at-root.yaml:3:3: ' + keydup,
+            './file-at-root.yaml:4:17: ' + trailing,
+            './file-at-root.yaml:5:5: ' + hyphen,
+            './file.dont-lint-me.yaml:3:3: ' + keydup,
+            './file.dont-lint-me.yaml:4:17: ' + trailing,
+            './file.dont-lint-me.yaml:5:5: ' + hyphen,
+            './ign-dup/file.yaml:3:3: ' + keydup,
+            './ign-dup/file.yaml:4:17: ' + trailing,
+            './ign-dup/file.yaml:5:5: ' + hyphen,
+            './ign-dup/sub/dir/file.yaml:3:3: ' + keydup,
+            './ign-dup/sub/dir/file.yaml:4:17: ' + trailing,
+            './ign-dup/sub/dir/file.yaml:5:5: ' + hyphen,
+            './ign-trail/file.yaml:3:3: ' + keydup,
+            './ign-trail/file.yaml:4:17: ' + trailing,
+            './ign-trail/file.yaml:5:5: ' + hyphen,
+            './include/ign-dup/sub/dir/file.yaml:3:3: ' + keydup,
+            './include/ign-dup/sub/dir/file.yaml:4:17: ' + trailing,
+            './include/ign-dup/sub/dir/file.yaml:5:5: ' + hyphen,
+            './s/s/ign-trail/file.yaml:3:3: ' + keydup,
+            './s/s/ign-trail/file.yaml:4:17: ' + trailing,
+            './s/s/ign-trail/file.yaml:5:5: ' + hyphen,
+            './s/s/ign-trail/s/s/file.yaml:3:3: ' + keydup,
+            './s/s/ign-trail/s/s/file.yaml:4:17: ' + trailing,
+            './s/s/ign-trail/s/s/file.yaml:5:5: ' + hyphen,
+            './s/s/ign-trail/s/s/file2.lint-me-anyway.yaml:3:3: ' + keydup,
+            './s/s/ign-trail/s/s/file2.lint-me-anyway.yaml:4:17: ' + trailing,
+            './s/s/ign-trail/s/s/file2.lint-me-anyway.yaml:5:5: ' + hyphen,
+        )))
+
+    def test_run_with_ignore(self):
+        with open(os.path.join(self.wd, '.yamllint'), 'w') as f:
+            f.write('extends: default\n'
+                    'ignore: |\n'
+                    '  *.dont-lint-me.yaml\n'
+                    '  /bin/\n'
+                    '  !/bin/*.lint-me-anyway.yaml\n'
+                    'rules:\n'
+                    '  key-duplicates:\n'
+                    '    ignore: |\n'
+                    '      /ign-dup\n'
+                    '  trailing-spaces:\n'
+                    '    ignore: |\n'
+                    '      ign-trail\n'
+                    '      !*.lint-me-anyway.yaml\n')
+
         sys.stdout = StringIO()
         with self.assertRaises(SystemExit):
             cli.run(('-f', 'parsable', '.'))
@@ -519,3 +592,108 @@ class IgnorePathConfigTestCase(unittest.TestCase):
             './s/s/ign-trail/s/s/file2.lint-me-anyway.yaml:4:17: ' + trailing,
             './s/s/ign-trail/s/s/file2.lint-me-anyway.yaml:5:5: ' + hyphen,
         )))
+
+    def test_run_with_ignore_from_file(self):
+        with open(os.path.join(self.wd, '.yamllint'), 'w') as f:
+            f.write('extends: default\n'
+                    'ignore-from-file: .gitignore\n')
+        with open(os.path.join(self.wd, '.gitignore'), 'w') as f:
+            f.write('*.dont-lint-me.yaml\n'
+                    '/bin/\n'
+                    '!/bin/*.lint-me-anyway.yaml\n')
+
+        sys.stdout = StringIO()
+        with self.assertRaises(SystemExit):
+            cli.run(('-f', 'parsable', '.'))
+
+        out = sys.stdout.getvalue()
+        out = '\n'.join(sorted(out.splitlines()))
+
+        docstart = '[warning] missing document start "---" (document-start)'
+        keydup = '[error] duplication of key "key" in mapping (key-duplicates)'
+        trailing = '[error] trailing spaces (trailing-spaces)'
+        hyphen = '[error] too many spaces after hyphen (hyphens)'
+
+        self.assertEqual(out, '\n'.join((
+            './.yamllint:1:1: ' + docstart,
+            './bin/file.lint-me-anyway.yaml:3:3: ' + keydup,
+            './bin/file.lint-me-anyway.yaml:4:17: ' + trailing,
+            './bin/file.lint-me-anyway.yaml:5:5: ' + hyphen,
+            './file-at-root.yaml:3:3: ' + keydup,
+            './file-at-root.yaml:4:17: ' + trailing,
+            './file-at-root.yaml:5:5: ' + hyphen,
+            './ign-dup/file.yaml:3:3: ' + keydup,
+            './ign-dup/file.yaml:4:17: ' + trailing,
+            './ign-dup/file.yaml:5:5: ' + hyphen,
+            './ign-dup/sub/dir/file.yaml:3:3: ' + keydup,
+            './ign-dup/sub/dir/file.yaml:4:17: ' + trailing,
+            './ign-dup/sub/dir/file.yaml:5:5: ' + hyphen,
+            './ign-trail/file.yaml:3:3: ' + keydup,
+            './ign-trail/file.yaml:4:17: ' + trailing,
+            './ign-trail/file.yaml:5:5: ' + hyphen,
+            './include/ign-dup/sub/dir/file.yaml:3:3: ' + keydup,
+            './include/ign-dup/sub/dir/file.yaml:4:17: ' + trailing,
+            './include/ign-dup/sub/dir/file.yaml:5:5: ' + hyphen,
+            './s/s/ign-trail/file.yaml:3:3: ' + keydup,
+            './s/s/ign-trail/file.yaml:4:17: ' + trailing,
+            './s/s/ign-trail/file.yaml:5:5: ' + hyphen,
+            './s/s/ign-trail/s/s/file.yaml:3:3: ' + keydup,
+            './s/s/ign-trail/s/s/file.yaml:4:17: ' + trailing,
+            './s/s/ign-trail/s/s/file.yaml:5:5: ' + hyphen,
+            './s/s/ign-trail/s/s/file2.lint-me-anyway.yaml:3:3: ' + keydup,
+            './s/s/ign-trail/s/s/file2.lint-me-anyway.yaml:4:17: ' + trailing,
+            './s/s/ign-trail/s/s/file2.lint-me-anyway.yaml:5:5: ' + hyphen,
+        )))
+
+    def test_run_with_ignored_from_file(self):
+        with open(os.path.join(self.wd, '.yamllint'), 'w') as f:
+            f.write('ignore-from-file: [.gitignore, .yamlignore]\n'
+                    'extends: default\n')
+        with open(os.path.join(self.wd, '.gitignore'), 'w') as f:
+            f.write('*.dont-lint-me.yaml\n'
+                    '/bin/\n')
+        with open(os.path.join(self.wd, '.yamlignore'), 'w') as f:
+            f.write('!/bin/*.lint-me-anyway.yaml\n')
+
+        sys.stdout = StringIO()
+        with self.assertRaises(SystemExit):
+            cli.run(('-f', 'parsable', '.'))
+
+        out = sys.stdout.getvalue()
+        out = '\n'.join(sorted(out.splitlines()))
+
+        docstart = '[warning] missing document start "---" (document-start)'
+        keydup = '[error] duplication of key "key" in mapping (key-duplicates)'
+        trailing = '[error] trailing spaces (trailing-spaces)'
+        hyphen = '[error] too many spaces after hyphen (hyphens)'
+
+        self.assertEqual(out, '\n'.join((
+            './.yamllint:1:1: ' + docstart,
+            './bin/file.lint-me-anyway.yaml:3:3: ' + keydup,
+            './bin/file.lint-me-anyway.yaml:4:17: ' + trailing,
+            './bin/file.lint-me-anyway.yaml:5:5: ' + hyphen,
+            './file-at-root.yaml:3:3: ' + keydup,
+            './file-at-root.yaml:4:17: ' + trailing,
+            './file-at-root.yaml:5:5: ' + hyphen,
+            './ign-dup/file.yaml:3:3: ' + keydup,
+            './ign-dup/file.yaml:4:17: ' + trailing,
+            './ign-dup/file.yaml:5:5: ' + hyphen,
+            './ign-dup/sub/dir/file.yaml:3:3: ' + keydup,
+            './ign-dup/sub/dir/file.yaml:4:17: ' + trailing,
+            './ign-dup/sub/dir/file.yaml:5:5: ' + hyphen,
+            './ign-trail/file.yaml:3:3: ' + keydup,
+            './ign-trail/file.yaml:4:17: ' + trailing,
+            './ign-trail/file.yaml:5:5: ' + hyphen,
+            './include/ign-dup/sub/dir/file.yaml:3:3: ' + keydup,
+            './include/ign-dup/sub/dir/file.yaml:4:17: ' + trailing,
+            './include/ign-dup/sub/dir/file.yaml:5:5: ' + hyphen,
+            './s/s/ign-trail/file.yaml:3:3: ' + keydup,
+            './s/s/ign-trail/file.yaml:4:17: ' + trailing,
+            './s/s/ign-trail/file.yaml:5:5: ' + hyphen,
+            './s/s/ign-trail/s/s/file.yaml:3:3: ' + keydup,
+            './s/s/ign-trail/s/s/file.yaml:4:17: ' + trailing,
+            './s/s/ign-trail/s/s/file.yaml:5:5: ' + hyphen,
+            './s/s/ign-trail/s/s/file2.lint-me-anyway.yaml:3:3: ' + keydup,
+            './s/s/ign-trail/s/s/file2.lint-me-anyway.yaml:4:17: ' + trailing,
+            './s/s/ign-trail/s/s/file2.lint-me-anyway.yaml:5:5: ' + hyphen,
+        )))

yamllint/config.py

@@ -13,6 +13,7 @@
 # You should have received a copy of the GNU General Public License
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
+import fileinput
 import os.path
 
 import pathspec
@@ -96,7 +97,21 @@ class YamlLintConfig:
             except Exception as e:
                 raise YamlLintConfigError('invalid config: %s' % e)
 
-        if 'ignore' in conf:
+        if 'ignore' in conf and 'ignore-from-file' in conf:
+            raise YamlLintConfigError(
+                'invalid config: ignore and ignore-from-file keys cannot be '
+                'used together')
+        elif 'ignore-from-file' in conf:
+            if isinstance(conf['ignore-from-file'], str):
+                conf['ignore-from-file'] = [conf['ignore-from-file']]
+            if not (isinstance(conf['ignore-from-file'], list) and all(
+                    isinstance(ln, str) for ln in conf['ignore-from-file'])):
+                raise YamlLintConfigError(
+                    'invalid config: ignore-from-file should contain '
+                    'filename(s), either as a list or string')
+            with fileinput.input(conf['ignore-from-file']) as f:
+                self.ignore = pathspec.PathSpec.from_lines('gitwildmatch', f)
+        elif 'ignore' in conf:
             if not isinstance(conf['ignore'], str):
                 raise YamlLintConfigError(
                     'invalid config: ignore should contain file patterns')
@@ -150,7 +165,7 @@ def validate_rule_conf(rule, conf):
         options = getattr(rule, 'CONF', {})
         options_default = getattr(rule, 'DEFAULT', {})
         for optkey in conf:
-            if optkey in ('ignore', 'level'):
+            if optkey in ('ignore', 'ignore-from-file', 'level'):
                 continue
             if optkey not in options:
                 raise YamlLintConfigError(