Add support for git-worktree

README.md

@@ -57,13 +57,6 @@ This project aims to support the following Ruby runtimes on both \*nix and Windo
 
 * MRI 2.x
 
-## Limitations
-
-Overcommit does not currently support
-[`git-worktree`](https://git-scm.com/docs/git-worktree) (introduced in Git 2.5),
-but there is an [open issue](https://github.com/brigade/overcommit/issues/336)
-tracking progress on adding support.
-
 ### Dependencies
 
 Some of the hooks have third-party dependencies. For example, to lint your

lib/overcommit/git_config.rb

@@ -14,7 +14,7 @@ def comment_character
     def hooks_path
       path = `git config --get core.hooksPath`.chomp
       return File.join(Overcommit::Utils.git_dir, 'hooks') if path.empty?
-      File.absolute_path(path)
+      File.absolute_path(path, Dir.pwd)
     end
   end
 end

lib/overcommit/utils.rb

@@ -43,38 +43,29 @@ def script_path(script)
       def repo_root
         @repo_root ||=
           begin
-            git_dir = Pathname.new(File.expand_path('.')).enum_for(:ascend).find do |path|
-              File.exist?(File.join(path, '.git'))
+            result = execute(%w[git rev-parse --show-toplevel])
+            unless result.success?
+              raise Overcommit::Exceptions::InvalidGitRepo,
+                    'Unable to determine location of GIT_DIR. ' \
+                    'Not a recognizable Git repository!'
             end
-
-            unless git_dir
-              raise Overcommit::Exceptions::InvalidGitRepo, 'no .git directory found'
-            end
-
-            git_dir.to_s
+            result.stdout.chomp("\n")
           end
       end
 
       # Returns an absolute path to the .git directory for a repo.
       #
-      # @param repo_dir [String] root directory of git repo
       # @return [String]
-      def git_dir(repo_dir = repo_root)
+      def git_dir
         @git_dir ||=
           begin
-            git_dir = File.expand_path('.git', repo_dir)
-
-            # .git could also be a file that contains the location of the git directory
-            unless File.directory?(git_dir)
-              git_dir = File.read(git_dir)[/^gitdir: (.*)$/, 1]
-
-              # Resolve relative paths
-              unless git_dir.start_with?('/')
-                git_dir = File.expand_path(git_dir, repo_dir)
-              end
+            result = execute(%w[git rev-parse --git-common-dir])
+            unless result.success?
+              raise Overcommit::Exceptions::InvalidGitRepo,
+                    'Unable to determine location of GIT_DIR. ' \
+                    'Not a recognizable Git repository!'
             end
-
-            git_dir
+            File.expand_path(result.stdout.chomp("\n"), Dir.pwd)
           end
       end
 

spec/overcommit/utils_spec.rb

@@ -52,27 +52,13 @@
       end
     end
 
-    context 'when .git is a file' do
-      before do
-        FileUtils.rm_rf('.git', secure: true)
-        echo("gitdir: #{git_dir_path}", '.git')
-      end
+    context 'when .git directory is not located in the repository' do
+      let(:git_dir) { Dir.mktmpdir }
+      let(:repo_dir) { repo(git_dir: git_dir) }
 
-      context 'and is a relative path' do
-        let(:git_dir_path) { '../.git' }
-
-        it 'returns the path contained in the file' do
-          # realpath is so spec passes on Mac OS X
-          subject.should == File.join(File.realpath(File.dirname(repo_dir)), '.git')
-        end
-      end
-
-      context 'and is an absolute path' do
-        let(:git_dir_path) { '/some/arbitrary/path/.git' }
-
-        it 'returns the path contained in the file' do
-          subject.should == git_dir_path
-        end
+      it 'returns the path of the external Git directory' do
+        # realpath is so spec passes on Mac OS X
+        subject.should == File.realpath(git_dir)
       end
     end
   end

spec/support/git_spec_helpers.rb

@@ -11,7 +11,12 @@ module GitSpecHelpers
   # @return [String] path of the repository
   def repo(options = {})
     directory('some-repo') do
-      `git init --template="#{options[:template_dir]}"`
+      create_cmd = %w[git init]
+      create_cmd += ['--template', options[:template_dir]] if options[:template_dir]
+      create_cmd += ['--separate-git-dir', options[:git_dir]] if options[:git_dir]
+
+      result = Overcommit::Utils.execute(create_cmd)
+      raise "Unable to create repo: #{result.stderr}" unless result.success?
 
       # Need to define user info since some CI contexts don't have defaults set
       `git config --local user.name "Overcommit Tester"`