Fix default exclusion of vendor directories

Excluding directories from a .rubocop.yml file works, but before this
fix, the setting of AllCops/Excludes in default.yml didn't have any
effect.

CHANGELOG.md

@@ -26,6 +26,7 @@
 * [#912](https://github.com/bbatsov/rubocop/issues/912): Handle top-level constant resolution in `DeprecatedClassMethods` (e.g. `::File.exists?`). ([@bbatsov][])
 * [#914](https://github.com/bbatsov/rubocop/issues/914): Fixed rdoc error during gem installation. ([@bbatsov][])
 * The `--only` option now enables the given cop in case it is disabled in configuration. ([@jonas054][])
+* Fix path resolution so that the default exclusion of `vendor` directories works. ([@jonas054][])
 
 ## 0.19.1 (17/03/2014)
 

lib/rubocop/config.rb

@@ -88,17 +88,19 @@ def patterns_to_exclude
     end
 
     def path_relative_to_config(path)
-      # Paths specified in .rubocop.yml files are relative to the directory
-      # where that file is. Paths in other config files are relative to the
-      # current directory. This is so that paths in config/default.yml, for
-      # example, are not relative to RuboCop's config directory since that
-      # wouldn't work.
-      base_dir = if File.basename(loaded_path) == ConfigLoader::DOTFILE
-                   File.dirname(loaded_path)
-                 else
-                   Dir.pwd
-                 end
-      relative_path(path, base_dir)
+      relative_path(path, base_dir_for_path_parameters)
+    end
+
+    # Paths specified in .rubocop.yml files are relative to the directory where
+    # that file is. Paths in other config files are relative to the current
+    # directory. This is so that paths in config/default.yml, for example, are
+    # not relative to RuboCop's config directory since that wouldn't work.
+    def base_dir_for_path_parameters
+      if File.basename(loaded_path) == ConfigLoader::DOTFILE
+        File.dirname(loaded_path)
+      else
+        Dir.pwd
+      end
     end
   end
 end

lib/rubocop/config_loader.rb

@@ -32,14 +32,15 @@ def load_file(path)
         hash.delete('inherit_from')
         config = Config.new(hash, path)
         config.warn_unless_valid
+        make_excludes_absolute(config)
         config
       end
 
       def make_excludes_absolute(config)
         if config['AllCops'] && config['AllCops']['Excludes']
           config['AllCops']['Excludes'].map! do |exclude_elem|
             if exclude_elem.is_a?(String) && !exclude_elem.start_with?('/')
-              File.join(File.dirname(config.loaded_path), exclude_elem)
+              File.join(config.base_dir_for_path_parameters, exclude_elem)
             else
               exclude_elem
             end
@@ -92,7 +93,6 @@ def configuration_from_file(config_file)
           print 'AllCops/Excludes ' if debug?
           add_excludes_from_higher_level(config, load_file(found_files.last))
         end
-        make_excludes_absolute(config)
         merge_with_default(config, config_file)
       end
 
@@ -124,9 +124,6 @@ def merge_with_default(config, config_file)
 
       def resolve_inheritance(path, hash)
         base_configs(path, hash['inherit_from']).reverse_each do |base_config|
-          if File.basename(base_config.loaded_path) == DOTFILE
-            make_excludes_absolute(base_config)
-          end
           base_config.each do |k, v|
             hash[k] = hash.key?(k) ? merge(v, hash[k]) : v if v.is_a?(Hash)
           end

spec/rubocop/cli_spec.rb

@@ -1538,6 +1538,17 @@ def interrupt
                 ''].join("\n"))
     end
 
+    it 'excludes the vendor directory by default' do
+      create_file('vendor/ex.rb',
+                  ['# encoding: utf-8',
+                   '#' * 90])
+
+      cli.run(%w(--format simple))
+      expect($stdout.string)
+        .to eq(['', '0 files inspected, no offenses detected',
+                ''].join("\n"))
+    end
+
     # Being immune to bad configuration files in excluded directories has
     # become important due to a bug in rubygems
     # (https://github.com/rubygems/rubygems/issues/680) that makes