Add support to cherry-pick any commit

Issue: https://gitlab.com/gitlab-org/gitlab-ce/issues/12785
Merge Request: https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/3514

3 files changed, 69 insertions, 43 deletions

diff --git a/app/services/commits/change_service.rb b/app/services/commits/change_service.rb
new file mode 100644
index 00000000000..6b69cb53b2c
--- /dev/null
+++ b/app/services/commits/change_service.rb
@@ -0,0 +1,47 @@
+module Commits
+  class ChangeService < ::BaseService
+    class ValidationError < StandardError; end
+    class ChangeError < StandardError; end
+
+    def execute
+      @source_project = params[:source_project] || @project
+      @target_branch = params[:target_branch]
+      @commit = params[:commit]
+      @create_merge_request = params[:create_merge_request].present?
+
+      check_push_permissions unless @create_merge_request
+      commit
+    rescue Repository::CommitError, Gitlab::Git::Repository::InvalidBlobName, GitHooksService::PreReceiveError,
+           ValidationError, ChangeError => ex
+      error(ex.message)
+    end
+
+    def commit
+      raise NotImplementedError
+    end
+
+    private
+
+    def check_push_permissions
+      allowed = ::Gitlab::GitAccess.new(current_user, project).can_push_to_branch?(@target_branch)
+
+      unless allowed
+        raise ValidationError.new('You are not allowed to push into this branch')
+      end
+
+      true
+    end
+    
+    def create_target_branch(new_branch)
+      # Temporary branch exists and contains the change commit
+      return success if repository.find_branch(new_branch)
+
+      result = CreateBranchService.new(@project, current_user)
+                                  .execute(new_branch, @target_branch, source_project: @source_project)
+
+      if result[:status] == :error
+        raise ChangeError, "There was an error creating the source branch: #{result[:message]}"
+      end
+    end
+  end
+end
diff --git a/app/services/commits/cherry_pick_service.rb b/app/services/commits/cherry_pick_service.rb
new file mode 100644
index 00000000000..f9a4efa7182
--- /dev/null
+++ b/app/services/commits/cherry_pick_service.rb
@@ -0,0 +1,19 @@
+module Commits
+  class CherryPickService < ChangeService
+    def commit
+      cherry_pick_into = @create_merge_request ? @commit.cherry_pick_branch_name : @target_branch
+      cherry_pick_tree_id = repository.check_cherry_pick_content(@commit, @target_branch)
+
+      if cherry_pick_tree_id
+        create_target_branch(cherry_pick_into) if @create_merge_request
+
+        repository.cherry_pick(current_user, @commit, cherry_pick_into, cherry_pick_tree_id)
+        success
+      else
+        error_msg = "Sorry, we cannot cherry-pick this #{@commit.change_type_title} automatically.
+                     It may have already been cherry-picked, or a more recent commit may have updated some of its content."
+        raise ChangeError, error_msg
+      end
+    end
+  end
+end
diff --git a/app/services/commits/revert_service.rb b/app/services/commits/revert_service.rb
index a3c950ede1f..c7de9f6f35e 100644
--- a/app/services/commits/revert_service.rb
+++ b/app/services/commits/revert_service.rb
@@ -1,21 +1,5 @@
 module Commits
-  class RevertService < ::BaseService
-    class ValidationError < StandardError; end
-    class ReversionError < StandardError; end
-
-    def execute
-      @source_project = params[:source_project] || @project
-      @target_branch = params[:target_branch]
-      @commit = params[:commit]
-      @create_merge_request = params[:create_merge_request].present?
-
-      check_push_permissions unless @create_merge_request
-      commit
-    rescue Repository::CommitError, Gitlab::Git::Repository::InvalidBlobName, GitHooksService::PreReceiveError,
-           ValidationError, ReversionError => ex
-      error(ex.message)
-    end
-
+  class RevertService < ChangeService
     def commit
       revert_into = @create_merge_request ? @commit.revert_branch_name : @target_branch
       revert_tree_id = repository.check_revert_content(@commit, @target_branch)
@@ -26,34 +10,10 @@ module Commits
         repository.revert(current_user, @commit, revert_into, revert_tree_id)
         success
       else
-        error_msg = "Sorry, we cannot revert this #{params[:revert_type_title]} automatically.
+        error_msg = "Sorry, we cannot revert this #{@commit.change_type_title} automatically.
                      It may have already been reverted, or a more recent commit may have updated some of its content."
-        raise ReversionError, error_msg
+        raise ChangeError, error_msg
       end
     end
-
-    private
-
-    def create_target_branch(new_branch)
-      # Temporary branch exists and contains the revert commit
-      return success if repository.find_branch(new_branch)
-
-      result = CreateBranchService.new(@project, current_user)
-                                  .execute(new_branch, @target_branch, source_project: @source_project)
-
-      if result[:status] == :error
-        raise ReversionError, "There was an error creating the source branch: #{result[:message]}"
-      end
-    end
-
-    def check_push_permissions
-      allowed = ::Gitlab::GitAccess.new(current_user, project).can_push_to_branch?(@target_branch)
-
-      unless allowed
-        raise ValidationError.new('You are not allowed to push into this branch')
-      end
-
-      true
-    end
   end
 end