add cookstyle support to fix #617

config/default.yml

@@ -230,6 +230,16 @@ PreCommit:
     install_command: 'npm install -g coffeelint'
     include: '**/*.coffee'
 
+  CookStyle:
+    enabled: false
+    description: 'Analyze with CookStyle'
+    required_executable: 'cookstyle'
+    flags: ['--format=emacs', '--force-exclusion', '--display-cop-names']
+    install_command: 'gem install cookstyle'
+    include:
+      - '**/*.rb'
+      - '**/*.erb'
+
   Credo:
     enabled: false
     description: 'Analyze with credo'

lib/overcommit/hook/pre_commit/cook_style.rb

@@ -0,0 +1,35 @@
+# frozen_string_literal: true
+
+module Overcommit::Hook::PreCommit
+  # Runs `cookstyle` against any modified Chef Ruby files.
+  #
+  # @see https://docs.chef.io/cookstyle.html
+  class CookStyle < Base
+    GENERIC_MESSAGE_TYPE_CATEGORIZER = lambda do |type|
+      type =~ /^warn/ ? :warning : :error
+    end
+
+    COP_MESSAGE_TYPE_CATEGORIZER = lambda do |type|
+      type.include?('W') ? :warning : :error
+    end
+
+    def run
+      result = execute(command, args: applicable_files)
+      return :pass if result.success?
+
+      generic_messages = extract_messages(
+        result.stderr.split("\n"),
+        /^(?<type>[a-z]+)/i,
+        GENERIC_MESSAGE_TYPE_CATEGORIZER,
+      )
+
+      cop_messages = extract_messages(
+        result.stdout.split("\n"),
+        /^(?<file>(?:\w:)?[^:]+):(?<line>\d+):[^ ]+ (?<type>[^ ]+)/,
+        COP_MESSAGE_TYPE_CATEGORIZER,
+      )
+
+      generic_messages + cop_messages
+    end
+  end
+end

spec/overcommit/hook/pre_commit/cook_style_spec.rb

@@ -0,0 +1,102 @@
+# frozen_string_literal: true
+
+require 'spec_helper'
+
+describe Overcommit::Hook::PreCommit::CookStyle do
+  let(:config)  { Overcommit::ConfigurationLoader.default_configuration }
+  let(:context) { double('context') }
+  subject { described_class.new(config, context) }
+
+  before do
+    subject.stub(:applicable_files).and_return(%w[file1.rb file2.rb])
+  end
+
+  context 'when cookstyle exits successfully' do
+    let(:result) { double('result') }
+
+    before do
+      result.stub(success?: true, stderr: '', stdout: '')
+      subject.stub(:execute).and_return(result)
+    end
+
+    it { should pass }
+
+    context 'and it printed warnings to stderr' do
+      before do
+        result.stub(:stderr).and_return(normalize_indent(<<-MSG))
+          warning: parser/current is loading parser/ruby21, which recognizes
+          warning: 2.1.8-compliant syntax, but you are running 2.1.1.
+          warning: please see https://github.com/whitequark/parser#compatibility-with-ruby-mri.
+        MSG
+      end
+
+      it { should pass }
+    end
+  end
+
+  context 'when cookstyle exits unsucessfully' do
+    let(:result) { double('result') }
+
+    before do
+      result.stub(:success?).and_return(false)
+      subject.stub(:execute).and_return(result)
+    end
+
+    context 'and it reports a warning' do
+      before do
+        result.stub(:stdout).and_return([
+          'file1.rb:1:1: W: Useless assignment to variable - my_var.',
+        ].join("\n"))
+        result.stub(:stderr).and_return('')
+      end
+
+      it { should warn }
+
+      context 'and it printed warnings to stderr' do
+        before do
+          result.stub(:stderr).and_return(normalize_indent(<<-MSG))
+            warning: parser/current is loading parser/ruby21, which recognizes
+            warning: 2.1.8-compliant syntax, but you are running 2.1.1.
+            warning: please see https://github.com/whitequark/parser#compatibility-with-ruby-mri.
+          MSG
+        end
+
+        it { should warn }
+      end
+    end
+
+    context 'and it reports an error' do
+      before do
+        result.stub(:stdout).and_return([
+          'file1.rb:1:1: C: Missing top-level class documentation',
+        ].join("\n"))
+        result.stub(:stderr).and_return('')
+      end
+
+      it { should fail_hook }
+
+      context 'and it printed warnings to stderr' do
+        before do
+          result.stub(:stderr).and_return(normalize_indent(<<-MSG))
+            warning: parser/current is loading parser/ruby21, which recognizes
+            warning: 2.1.8-compliant syntax, but you are running 2.1.1.
+            warning: please see https://github.com/whitequark/parser#compatibility-with-ruby-mri.
+          MSG
+        end
+
+        it { should fail_hook }
+      end
+    end
+
+    context 'when a generic error message is written to stderr' do
+      before do
+        result.stub(:stdout).and_return('')
+        result.stub(:stderr).and_return([
+          'Could not find cookstyle in any of the sources'
+        ].join("\n"))
+      end
+
+      it { should fail_hook }
+    end
+  end
+end