Check if branch contains commit

This allows the user to see if an arbitrary commit is contained within a branch. For example you can check to see if a branch was merged into master with `git.branch('master').contains?('feature')`. Or you can see if your feature branch has the latest master commit with `git.branch('feature').contains?('master')`
ruby-git · perlun · Jul 12, 2018 · Aug 29, 2014 · Jun 4, 2018 · Jun 26, 2018
commit de848e460c41380c3ffe40498519407a40a7ecfd
diff --git a/README.md b/README.md
@@ -203,6 +203,7 @@ And here are the operations that will need to write to your git repository.
      g.branch('new_branch').checkout
      g.branch('new_branch').delete
      g.branch('existing_branch').checkout
+     g.branch('master').contains?('existing_branch')
 
      g.checkout('new_branch')
      g.checkout(g.branch('new_branch'))

diff --git a/lib/git/branch.rb b/lib/git/branch.rb
@@ -60,6 +60,10 @@ def current
       determine_current
     end
 
+    def contains?(commit)
+      !@base.lib.branch_contains(commit, self.name).empty?
+    end
+
     def merge(branch = nil, message = nil)
       if branch
         in_branch do 

diff --git a/lib/git/lib.rb b/lib/git/lib.rb
@@ -317,6 +317,9 @@ def branch_current
       branches_all.select { |b| b[1] }.first[0] rescue nil
     end
 
+    def branch_contains(commit, branch_name="")
+      command("branch",  [branch_name, "--contains", commit])
+    end
 
     # returns hash
     # [tree-ish] = [[line_no, match], [line_no, match2]]

diff --git a/tests/units/test_branch.rb b/tests/units/test_branch.rb
@@ -44,6 +44,14 @@ def test_branches_single
     end
   end
 
+  def test_true_branch_contains?
+    assert(@git.branch('git_grep').contains?('master'))
+  end
+
+  def test_false_branch_contains?
+    assert(!@git.branch('master').contains?('git_grep'))
+  end
+
   def test_branch_commit
     assert_equal(270, @git.branches[:test_branches].gcommit.size)
   end