git-bisect.patch

From fad23f414a762d74bdcd77290ef206110327bb46 Mon Sep 17 00:00:00 2001
From: Dmitry Maksimov <[email protected]>
Date: Tue, 16 Mar 2010 08:47:04 +0300
Subject: [PATCH] Basic implementation of git-bisect

---
 lib/grit.rb                |    1 +
 lib/grit/bisect.rb         |   37 +++++++++++++++++++++++++++++++++
 lib/grit/git.rb            |    4 +++
 lib/grit/repo.rb           |   20 ++++++++++++++++++
 test/test_bisect.rb        |   31 +++++++++++++++++++++++++++
 test/test_bisect_object.rb |   49 ++++++++++++++++++++++++++++++++++++++++++++
 test/test_git.rb           |    5 ++++
 7 files changed, 147 insertions(+), 0 deletions(-)
 create mode 100644 lib/grit/bisect.rb
 create mode 100644 test/test_bisect.rb
 create mode 100644 test/test_bisect_object.rb

diff --git a/lib/grit.rb b/lib/grit.rb
index d6f6148..426a2d9 100644
--- a/lib/grit.rb
+++ b/lib/grit.rb
@@ -50,6 +50,7 @@ require 'grit/status'
 require 'grit/submodule'
 require 'grit/blame'
 require 'grit/merge'
+require 'grit/bisect'
 
 
 module Grit
diff --git a/lib/grit/bisect.rb b/lib/grit/bisect.rb
new file mode 100644
index 0000000..092150e
--- /dev/null
+++ b/lib/grit/bisect.rb
@@ -0,0 +1,37 @@
+module Grit
+
+  class BisectObject
+    def initialize(git)
+      @git = git
+    end
+
+    def good(ref = nil)
+      response = @git.bisect(:good, ref)
+      parse_response(response)
+    end
+
+    def bad(ref = nil)
+      response = @git.bisect(:bad, ref)
+      parse_response(response)
+    end
+
+    def start
+      @git.bisect(:start)
+    end
+
+    def reset
+      @git.bisect(:reset)
+    end
+
+  private
+    def parse_response(response)
+      first_line = response.first
+      return nil if first_line.match(/^Bisecting:/)
+      return first_line.split.first if first_line.match(/is\sthe\sfirst\sbad\scommit$/) # broken commit sha
+
+      raise Exception, "Grit::BisectObject#parse_response is outdated"
+    end
+
+  end # BisectObject
+
+end # Grit
diff --git a/lib/grit/git.rb b/lib/grit/git.rb
index 1831fe2..5d83a46 100644
--- a/lib/grit/git.rb
+++ b/lib/grit/git.rb
@@ -183,6 +183,10 @@ module Grit
       false
     end
 
+    def bisect(subcommand, *args)
+      run("", "bisect #{subcommand.to_s}", "", {}, args.compact)
+    end
+
     # RAW CALLS WITH ENV SETTINGS
     def raw_git_call(command, index)
       tmp = ENV['GIT_INDEX_FILE']
diff --git a/lib/grit/repo.rb b/lib/grit/repo.rb
index 9eb3354..8a72a89 100644
--- a/lib/grit/repo.rb
+++ b/lib/grit/repo.rb
@@ -477,6 +477,26 @@ module Grit
     def inspect
       %Q{#<Grit::Repo "#{@path}">}
     end
+
+    # Find a broken commit using git bisect
+    #  +good_commit_ref+ is the reference to the last good commit
+    #  +bad_commit_ref+ is the reference to the bad commit, by default points to HEAD
+    #
+    # Returns nothing
+    def bisect(good_commit_ref, bad_commit_ref = nil, &block)
+      if block
+        bisect_obj = BisectObject.new(self.git)
+        bisect_obj.start
+        bisect_obj.bad(bad_commit_ref)
+        bisect_obj.good(good_commit_ref)
+
+        yield bisect_obj
+
+        bisect_obj.reset
+      else
+        raise ArgumentError, "A code block should be passed to Repo#bisect"
+      end
+    end
   end # Repo
 
 end # Grit
diff --git a/test/test_bisect.rb b/test/test_bisect.rb
new file mode 100644
index 0000000..68d1948
--- /dev/null
+++ b/test/test_bisect.rb
@@ -0,0 +1,31 @@
+require File.dirname(__FILE__) + '/helper'
+
+class TestBisect < Test::Unit::TestCase
+
+  def setup
+    @r = Repo.new(File.join(File.dirname(__FILE__), %w[dot_git]), :is_bare => true)
+
+    @good_commit = "d6016bc9fa3950ad18e3028f9d2d26f831061a62"
+    @bad_commit  = "ca8a30f5a7f0f163bbe3b6f0abf18a6c83b0687a"
+  end
+
+  def test_bisect_with_empty_block
+    assert_raise ArgumentError do
+      @r.bisect(@good_commit)
+    end
+  end
+
+  def test_bisect_calls
+    bisect_obj = mock("BisectObject instance")
+    bisect_obj.expects(:start)
+    bisect_obj.expects(:bad).with(@bad_commit)
+    bisect_obj.expects(:good).with(@good_commit)
+    bisect_obj.expects(:reset)
+
+    BisectObject.expects(:new).returns(bisect_obj)
+
+    @r.bisect(@good_commit, @bad_commit) do |b|
+    end
+  end
+
+end
diff --git a/test/test_bisect_object.rb b/test/test_bisect_object.rb
new file mode 100644
index 0000000..abc02e3
--- /dev/null
+++ b/test/test_bisect_object.rb
@@ -0,0 +1,49 @@
+require File.dirname(__FILE__) + '/helper'
+
+class TestBisectObject < Test::Unit::TestCase
+
+  def setup
+    @git_mock = mock("git")
+    @bisect_obj = BisectObject.new(@git_mock)
+  end
+
+  def test_start
+    @git_mock.expects(:bisect).with(:start)
+    @bisect_obj.start
+  end
+
+  def test_reset
+    @git_mock.expects(:bisect).with(:reset)
+    @bisect_obj.reset
+  end
+
+  def test_bad
+    @git_mock.expects(:bisect).with(:bad, nil).returns("Bisecting: ...")
+    @bisect_obj.bad
+  end
+
+  def test_good
+    @git_mock.expects(:bisect).with(:good, nil).returns("Bisecting: ...")
+    @bisect_obj.good
+  end
+
+  def test_parse_response_returns_nil
+    @git_mock.stubs(:bisect).with(:bad, nil).returns("Bisecting: ...")
+    assert_equal nil, @bisect_obj.bad
+  end
+
+  def test_parse_response_returns_commit_sha
+    sha = "d6016bc9fa3950ad18e3028f9d2d26f831061a62"
+
+    @git_mock.stubs(:bisect).with(:good, nil).returns("#{sha} is the first bad commit\n")
+    assert sha, @bisect_obj.good
+  end
+
+  def test_parse_response_raises_error
+    @git_mock.stubs(:bisect).with(:bad, nil).returns("Someting changed in git bisect messages\n")
+    assert_raise Exception do
+      @bisect_obj.bad
+    end
+  end
+
+end
diff --git a/test/test_git.rb b/test/test_git.rb
index 1d9d9e0..1a95363 100644
--- a/test/test_git.rb
+++ b/test/test_git.rb
@@ -101,4 +101,9 @@ class TestGit < Test::Unit::TestCase
     FileUtils.expects(:rm_rf).with(File.join(@git.git_dir, 'foo'))
     @git.fs_delete('foo')
   end
+
+  def test_bisect
+    @git.expects(:run).with("", "bisect start", "", {}, [])
+    @git.bisect(:start)
+  end
 end
-- 
1.6.3.3