[Fix 4245] Add --only-recognized-file-types and change default

The default for file names on the command line that are not recognized as a
Ruby file now becomes to inspect the files. With the
--only-recognized-file-types option, the old behavior of skipping the file is
kept.

CHANGELOG.md

@@ -26,6 +26,7 @@
 
 * [#7860](https://github.com/rubocop-hq/rubocop/issues/7860): Change `AllowInHeredoc` option of `Layout/TrailingWhitespace` to `true` by default. ([@koic][])
 * [#7094](https://github.com/rubocop-hq/rubocop/issues/7094): Clarify alignment in `Layout/MultilineOperationIndentation`. ([@jonas054][])
+* [#4245](https://github.com/rubocop-hq/rubocop/issues/4245): **(Breaking)** Inspect all files given on command line unless `--only-recognized-file-types` is given. ([@jonas054][])
 * [#7390](https://github.com/rubocop-hq/rubocop/issues/7390): **(Breaking)** Enabling a cop overrides disabling its department. ([@jonas054][])
 
 ## 0.82.0 (2020-04-16)

lib/rubocop/options.rb

@@ -103,6 +103,7 @@ def add_cop_selection_csv_option(option, opts)
     def add_configuration_options(opts)
       option(opts, '-c', '--config FILE')
       option(opts, '--force-exclusion')
+      option(opts, '--only-recognized-file-types')
       option(opts, '--ignore-parent-exclusion')
       option(opts, '--force-default-config')
       add_auto_gen_options(opts)
@@ -415,6 +416,9 @@ module OptionsHelp
       force_exclusion:                  ['Force excluding files specified in the',
                                          'configuration `Exclude` even if they are',
                                          'explicitly passed as arguments.'],
+      only_recognized_file_types:       ['Inspect files given on the command line only if',
+                                         'they are listed in AllCops/Include parameters',
+                                         'of user configuration or default configuration.'],
       ignore_disable_comments:          ['Run cops even when they are disabled locally',
                                          'with a comment.'],
       ignore_parent_exclusion:          ['Prevent from inheriting AllCops/Exclude from',

lib/rubocop/runner.rb

@@ -61,7 +61,12 @@ def warm_cache(target_files)
 
     def find_target_files(paths)
       target_finder = TargetFinder.new(@config_store, @options)
-      target_files = target_finder.find(paths, :only_recognized_file_types)
+      mode = if @options[:only_recognized_file_types]
+               :only_recognized_file_types
+             else
+               :all_file_types
+             end
+      target_files = target_finder.find(paths, mode)
       target_files.each(&:freeze).freeze
     end
 

manual/basic_usage.md

@@ -128,6 +128,7 @@ Command flag                    | Description
 `-F/--fail-fast`                | Inspect files in order of modification time and stops after first file with offenses.
 `   --fail-level`               | Minimum [severity](configuration.md#severity) for exit with error code. Full severity name or upper case initial can be given. Normally, auto-corrected offenses are ignored. Use `A` or `autocorrect` if you'd like them to trigger failure.
 `   --force-exclusion`          | Force excluding files specified in the configuration `Exclude` even if they are explicitly passed as arguments.
+`   --only-recognized-file-types` | Inspect files given on the command line only if they are listed in `AllCops`/`Include` parameters of user configuration or default configuration.
 `-h/--help`                     | Print usage information.
 `   --ignore-parent-exclusion`  | Ignores all Exclude: settings from all .rubocop.yml files present in parent folders. This is useful when you are importing submodules when you want to test them without being affected by the parent module's rubocop settings.
 `   --init`                     | Generate a .rubocop.yml file in the current directory.

spec/rubocop/cli/cli_options_spec.rb

@@ -1542,6 +1542,41 @@ def f
     end
   end
 
+  describe '--only-recognized-file-types' do
+    let(:target_file) { 'example.something' }
+    let(:exit_code) { cli.run(['--only-recognized-file-types', target_file]) }
+
+    before do
+      create_file(target_file, '#' * 90)
+    end
+
+    context 'when explicitly included' do
+      before do
+        create_file('.rubocop.yml', <<~YAML)
+          AllCops:
+            Include:
+              - #{target_file}
+        YAML
+      end
+
+      it 'includes the file given on the command line' do
+        expect(exit_code).to eq(1)
+      end
+    end
+
+    context 'when not explicitly included' do
+      it 'does not include the file given on the command line' do
+        expect(exit_code).to eq(0)
+      end
+
+      context 'but option is not given' do
+        it 'includes the file given on the command line' do
+          expect(cli.run([target_file])).to eq(1)
+        end
+      end
+    end
+  end
+
   describe '--stdin' do
     it 'causes source code to be read from stdin' do
       begin

spec/rubocop/options_spec.rb

@@ -43,6 +43,9 @@ def abs(path)
                   --force-exclusion            Force excluding files specified in the
                                                configuration `Exclude` even if they are
                                                explicitly passed as arguments.
+                  --only-recognized-file-types Inspect files given on the command line only if
+                                               they are listed in AllCops/Include parameters
+                                               of user configuration or default configuration.
                   --ignore-parent-exclusion    Prevent from inheriting AllCops/Exclude from
                                                parent folders.
                   --force-default-config       Use default configuration even if configuration