configuration: Allow using a list of strings in ignore configuration

This may feel more natural for some users, rather than embedding
multiple entries in a multi-line string.

docs/configuration.rst

@@ -140,7 +140,8 @@ Ignoring paths
 --------------
 
 It is possible to exclude specific files or directories, so that the linter
-doesn't process them.
+doesn't process them. They can be provided either as a list of paths, or as a
+bulk string.
 
 You can either totally ignore files (they won't be looked at):
 
@@ -153,6 +154,13 @@ You can either totally ignore files (they won't be looked at):
    all/this/directory/
    *.template.yaml
 
+ # or:
+
+ ignore:
+   - /this/specific/file.yaml
+   - all/this/directory/
+   - '*.template.yaml'
+
 or ignore paths only for specific rules:
 
 .. code-block:: yaml
@@ -165,6 +173,14 @@ or ignore paths only for specific rules:
        /this-file-has-trailing-spaces-but-it-is-OK.yaml
        /generated/*.yaml
 
+ # or:
+
+ rules:
+   trailing-spaces:
+     ignore:
+       - /this-file-has-trailing-spaces-but-it-is-OK.yaml
+       - /generated/*.yaml
+
 Note that this ``.gitignore``-style path pattern allows complex path
 exclusion/inclusion, see the `pathspec README file
 <https://pypi.python.org/pypi/pathspec>`_ for more details.

tests/test_config.py

@@ -369,7 +369,7 @@ class ExtendedConfigTestCase(unittest.TestCase):
         self.assertEqual(c.rules['colons']['max-spaces-before'], 0)
         self.assertEqual(c.rules['colons']['max-spaces-after'], 1)
 
-    def test_extended_ignore(self):
+    def test_extended_ignore_str(self):
         with tempfile.NamedTemporaryFile('w') as f:
             f.write('ignore: |\n'
                     '  *.template.yaml\n')
@@ -379,6 +379,16 @@ class ExtendedConfigTestCase(unittest.TestCase):
         self.assertEqual(c.ignore.match_file('test.template.yaml'), True)
         self.assertEqual(c.ignore.match_file('test.yaml'), False)
 
+    def test_extended_ignore_list(self):
+        with tempfile.NamedTemporaryFile('w') as f:
+            f.write('ignore:\n'
+                    '  - "*.template.yaml"\n')
+            f.flush()
+            c = config.YamlLintConfig('extends: ' + f.name + '\n')
+
+        self.assertEqual(c.ignore.match_file('test.template.yaml'), True)
+        self.assertEqual(c.ignore.match_file('test.yaml'), False)
+
 
 class ExtendedLibraryConfigTestCase(unittest.TestCase):
     def test_extend_config_disable_rule(self):
@@ -539,7 +549,7 @@ class IgnoreConfigTestCase(unittest.TestCase):
             './s/s/ign-trail/s/s/file2.lint-me-anyway.yaml:5:5: ' + hyphen,
         )))
 
-    def test_run_with_ignore(self):
+    def test_run_with_ignore_str(self):
         with open(os.path.join(self.wd, '.yamllint'), 'w') as f:
             f.write('extends: default\n'
                     'ignore: |\n'
@@ -593,6 +603,60 @@ class IgnoreConfigTestCase(unittest.TestCase):
             './s/s/ign-trail/s/s/file2.lint-me-anyway.yaml:5:5: ' + hyphen,
         )))
 
+    def test_run_with_ignore_list(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', '.'))
+
+        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:4:17: ' + trailing,
+            './ign-dup/file.yaml:5:5: ' + hyphen,
+            './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: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:5:5: ' + hyphen,
+            './s/s/ign-trail/s/s/file.yaml:3:3: ' + keydup,
+            './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_from_file(self):
         with open(os.path.join(self.wd, '.yamllint'), 'w') as f:
             f.write('extends: default\n'

yamllint/config.py

@@ -112,11 +112,16 @@ class YamlLintConfig:
             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):
+            if isinstance(conf['ignore'], str):
+                self.ignore = pathspec.PathSpec.from_lines(
+                    'gitwildmatch', conf['ignore'].splitlines())
+            elif (isinstance(conf['ignore'], list) and
+                    all(isinstance(line, str) for line in conf['ignore'])):
+                self.ignore = pathspec.PathSpec.from_lines(
+                    'gitwildmatch', conf['ignore'])
+            else:
                 raise YamlLintConfigError(
                     'invalid config: ignore should contain file patterns')
-            self.ignore = pathspec.PathSpec.from_lines(
-                'gitwildmatch', conf['ignore'].splitlines())
 
         if 'yaml-files' in conf:
             if not (isinstance(conf['yaml-files'], list)
@@ -150,11 +155,16 @@ def validate_rule_conf(rule, conf):
     if isinstance(conf, dict):
         if ('ignore' in conf and
                 not isinstance(conf['ignore'], pathspec.pathspec.PathSpec)):
-            if not isinstance(conf['ignore'], str):
+            if isinstance(conf['ignore'], str):
+                conf['ignore'] = pathspec.PathSpec.from_lines(
+                    'gitwildmatch', conf['ignore'].splitlines())
+            elif (isinstance(conf['ignore'], list) and
+                    all(isinstance(line, str) for line in conf['ignore'])):
+                conf['ignore'] = pathspec.PathSpec.from_lines(
+                    'gitwildmatch', conf['ignore'])
+            else:
                 raise YamlLintConfigError(
                     'invalid config: ignore should contain file patterns')
-            conf['ignore'] = pathspec.PathSpec.from_lines(
-                'gitwildmatch', conf['ignore'].splitlines())
 
         if 'level' not in conf:
             conf['level'] = 'error'