Add support for --stdin-filename

When other tools, like automatic linters within editors, run a sample
through reek, they typically do so via stdin. However, if there are reek
config exceptions to apply to that file, then reek has no way of knowing
what the original filename was, triggering false positives.

This adds an `--stdin-filename` CLI option that takes the
original filename, and passes it through to the Examiner and SourceCode
file to use as the `origin` attribute, allowing the configuration
directives to apply.

features/command_line_interface/options.feature

@@ -44,6 +44,7 @@ Feature: Reek can be controlled using command-line options
               --smell SMELL                Only look for a specific smell.
                                            Call it like this: reek --smell MissingSafeMethod source.rb
                                            Check out https://github.com/troessner/reek/blob/v4.8.1/docs/Code-Smells.md for a list of smells
+              --stdin-filename FILE        When passing code in via pipe, assume this filename when checking file or directory rules in the config.
 
       Generate a todo list:
           -t, --todo                       Generate a todo list

features/command_line_interface/stdin.feature

@@ -41,3 +41,32 @@ Feature: Reek reads from $stdin when no files are given
         [2]:Syntax: This file has unexpected token $end
         [1]:Syntax: This file has unexpected token tEQL
       """
+
+  Scenario: providing a filename to use for the config to match against
+    Given a file named "web_app/config.reek" with:
+      """
+      ---
+      directories:
+        "web_app/app/controllers":
+          IrresponsibleModule:
+            enabled: false
+          NestedIterators:
+            enabled: false
+          InstanceVariableAssumption:
+            enabled: false
+      """
+    When I pass a stdin to reek --config web_app/config.reek --stdin-filename web_app/app/controllers/users_controller with:
+      """
+      class UsersController < ApplicationController
+        def show
+          respond_with do |format|
+            format.json { |json| @user.to_custom_json }
+            format.xml { |xml| @user.to_fancy_xml }
+          end
+        end
+      end
+      """
+    Then it succeeds
+
+
+

features/step_definitions/reek_steps.rb

@@ -6,6 +6,10 @@
   reek_with_pipe(stdin, args)
 end
 
+When /^I pass a stdin to reek *(.*) with:$/ do |args, stdin|
+  reek_with_pipe(stdin, args)
+end
+
 Then /^it reports nothing$/ do
   expect(last_command_started).to have_output_on_stdout('')
 end

lib/reek/cli/command/report_command.rb

@@ -4,6 +4,7 @@
 require_relative '../../examiner'
 require_relative '../../logging_error_handler'
 require_relative '../../report'
+require_relative '../../source/source_code'
 
 module Reek
   module CLI
@@ -24,6 +25,7 @@ def execute
         def populate_reporter_with_smells
           sources.each do |source|
             reporter.add_examiner Examiner.new(source,
+                                               stdin_filename: options.stdin_filename,
                                                filter_by_smells: smell_names,
                                                configuration: configuration,
                                                error_handler: LoggingErrorHandler.new)

lib/reek/cli/options.rb

@@ -28,6 +28,7 @@ class Options
                     :show_empty,
                     :show_links,
                     :sorting,
+                    :stdin_filename,
                     :success_exit_code,
                     :failure_exit_code,
                     :generate_todo_list,
@@ -98,7 +99,7 @@ def set_banner
         BANNER
       end
 
-      # :reek:TooManyStatements { max_statements: 6 }
+      # :reek:TooManyStatements { max_statements: 7 }
       def set_configuration_options
         parser.separator 'Configuration:'
         parser.on('-c', '--config FILE', 'Read configuration options from FILE') do |file|
@@ -111,6 +112,11 @@ def set_configuration_options
                   'for a list of smells') do |smell|
           smells_to_detect << smell
         end
+        parser.on('--stdin-filename FILE',
+                  'When passing code in via pipe, assume this filename when '\
+                  'checking file or directory rules in the config.') do |file|
+          self.stdin_filename = Pathname.new(file)
+        end
       end
 
       def set_generate_todo_list_options

lib/reek/examiner.rb

@@ -33,12 +33,14 @@ def handle(_exception)
     #   The configuration for this Examiner.
     #
     # @public
+    # :reek:LongParameterList { max_params: 6 }
     def initialize(source,
+                   stdin_filename: nil,
                    filter_by_smells: [],
                    configuration: Configuration::AppConfiguration.default,
                    detector_repository_class: DetectorRepository,
                    error_handler: NullHandler.new)
-      @source              = Source::SourceCode.from(source)
+      @source              = Source::SourceCode.from(source, filename: stdin_filename)
       @smell_types         = detector_repository_class.eligible_smell_types(filter_by_smells)
       @detector_repository = detector_repository_class.new(smell_types: @smell_types,
                                                            configuration: configuration.directive_for(description))
@@ -49,7 +51,7 @@ def initialize(source,
     #
     # @public
     def origin
-      @origin ||= source.origin
+      source.origin
     end
 
     # @return [String] description of the source being analysed

lib/reek/source/source_code.rb

@@ -59,12 +59,13 @@ def initialize(code:, origin:, parser: self.class.default_parser)
       #
       # @return an instance of SourceCode
       # :reek:DuplicateMethodCall { max_calls: 2 }
-      def self.from(source)
+      # :reek:ControlParameter
+      def self.from(source, filename: nil)
         case source
         when File     then new(code: source.read,           origin: source.path)
-        when IO       then new(code: source.readlines.join, origin: IO_IDENTIFIER)
+        when IO       then new(code: source.readlines.join, origin: filename || IO_IDENTIFIER)
         when Pathname then new(code: source.read,           origin: source.to_s)
-        when String   then new(code: source,                origin: STRING_IDENTIFIER)
+        when String   then new(code: source,                origin: filename || STRING_IDENTIFIER)
         end
       end
 

spec/reek/cli/application_spec.rb

@@ -44,6 +44,18 @@
                configuration: Reek::Configuration::AppConfiguration,
                options: Reek::CLI::Options)
       end
+
+      context 'when a stdin filename is provided' do
+        let(:app) { described_class.new ['--stdin-filename', 'foo.rb'] }
+
+        it 'assumes that filename' do
+          app.execute
+          expect(Reek::CLI::Command::ReportCommand).to have_received(:new).
+            with(sources: [$stdin],
+                 configuration: Reek::Configuration::AppConfiguration,
+                 options: Reek::CLI::Options)
+        end
+      end
     end
 
     context 'when no source files given and no input was piped' do