config: validate ignore-from-file in validate_rule_conf

This fixes commit 2f8ad70 "config: Implement for `ignore-from-file`
option" that lacked rule config validation.

Closes #542.

tests/test_config.py

@@ -212,6 +212,14 @@ def test_invalid_rule_ignore(self):
                                   '  colons:\n'
                                   '    ignore: yes\n')
 
+    def test_invalid_rule_ignore_from_file(self):
+        self.assertRaises(
+            config.YamlLintConfigError,
+            config.YamlLintConfig,
+            'rules:\n'
+            '  colons:\n'
+            '    ignore-from-file: 1337\n')
+
     def test_invalid_locale(self):
         with self.assertRaisesRegex(
                 config.YamlLintConfigError,
@@ -660,12 +668,19 @@ def test_run_with_ignore_list(self):
     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')
+                    'ignore-from-file: .gitignore\n'
+                    'rules:\n'
+                    '  key-duplicates:\n'
+                    '    ignore-from-file: .ignore-key-duplicates\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')
 
+        with open(os.path.join(self.wd, '.ignore-key-duplicates'), 'w') as f:
+            f.write('/ign-dup\n')
+
         sys.stdout = StringIO()
         with self.assertRaises(SystemExit):
             cli.run(('-f', 'parsable', '.'))
@@ -686,10 +701,8 @@ def test_run_with_ignore_from_file(self):
             './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,

yamllint/config.py

@@ -153,8 +153,21 @@ def validate_rule_conf(rule, conf):
         return False
 
     if isinstance(conf, dict):
-        if ('ignore' in conf and
-                not isinstance(conf['ignore'], pathspec.pathspec.PathSpec)):
+        if ('ignore-from-file' in conf and not isinstance(
+                conf['ignore-from-file'], pathspec.pathspec.PathSpec)):
+            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(line, str)
+                            for line in conf['ignore-from-file'])):
+                raise YamlLintConfigError(
+                    'invalid config: ignore-from-file should contain '
+                    'valid filename(s), either as a list or string')
+            with fileinput.input(conf['ignore-from-file']) as f:
+                conf['ignore'] = pathspec.PathSpec.from_lines(
+                    'gitwildmatch', f)
+        elif ('ignore' in conf and not isinstance(
+                conf['ignore'], pathspec.pathspec.PathSpec)):
             if isinstance(conf['ignore'], str):
                 conf['ignore'] = pathspec.PathSpec.from_lines(
                     'gitwildmatch', conf['ignore'].splitlines())