1 files changed, 59 insertions, 0 deletions
diff --git a/app/services/commits/revert_service.rb b/app/services/commits/revert_service.rb
new file mode 100644
index 00000000000..a3c950ede1f
--- /dev/null
+++ b/app/services/commits/revert_service.rb
@@ -0,0 +1,59 @@
+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
+
+    def commit
+      revert_into = @create_merge_request ? @commit.revert_branch_name : @target_branch
+      revert_tree_id = repository.check_revert_content(@commit, @target_branch)
+
+      if revert_tree_id
+        create_target_branch(revert_into) if @create_merge_request
+
+        repository.revert(current_user, @commit, revert_into, revert_tree_id)
+        success
+      else
+        error_msg = "Sorry, we cannot revert this #{params[:revert_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
+      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