support `/merge` slash comand for MRs

7 files changed, 51 insertions, 7 deletions

diff --git a/app/controllers/projects/notes_controller.rb b/app/controllers/projects/notes_controller.rb
index b71509f2c9b..c5d93ce25bc 100644
--- a/app/controllers/projects/notes_controller.rb
+++ b/app/controllers/projects/notes_controller.rb
@@ -23,7 +23,8 @@ class Projects::NotesController < Projects::ApplicationController
   end
 
   def create
-    @note = Notes::CreateService.new(project, current_user, note_params).execute
+    create_params = note_params.merge(merge_request_diff_head_sha: params[:merge_request_diff_head_sha])
+    @note = Notes::CreateService.new(project, current_user, create_params).execute
 
     if @note.is_a?(Note)
       Banzai::NoteRenderer.render([@note], @project, current_user)
diff --git a/app/models/merge_request.rb b/app/models/merge_request.rb
index 70005a87f4b..10251302db8 100644
--- a/app/models/merge_request.rb
+++ b/app/models/merge_request.rb
@@ -898,10 +898,22 @@ class MergeRequest < ActiveRecord::Base
   end
 
   def has_commits?
-    commits_count > 0
+    merge_request_diff && commits_count > 0
   end
 
   def has_no_commits?
     !has_commits?
   end
+
+  def mergeable_with_slash_command?(current_user, autocomplete_precheck: false, last_diff_sha: nil)
+    return false unless can_be_merged_by?(current_user)
+
+    return true if autocomplete_precheck
+
+    return false unless mergeable?(skip_ci_check: true)
+    return false if head_pipeline && !(head_pipeline.success? || head_pipeline.active?)
+    return false if last_diff_sha != diff_head_sha
+
+    true
+  end
 end
diff --git a/app/services/merge_requests/update_service.rb b/app/services/merge_requests/update_service.rb
index ad16ef8c70f..3cb9aae83f6 100644
--- a/app/services/merge_requests/update_service.rb
+++ b/app/services/merge_requests/update_service.rb
@@ -7,6 +7,8 @@ module MergeRequests
       params.except!(:target_project_id)
       params.except!(:source_branch)
 
+      merge_from_slash_command(merge_request) if params[:merge]
+
       if merge_request.closed_without_fork?
         params.except!(:target_branch, :force_remove_source_branch)
       end
@@ -69,6 +71,19 @@ module MergeRequests
       end
     end
 
+    def merge_from_slash_command(merge_request)
+      last_diff_sha = params.delete(:merge)
+      return unless merge_request.mergeable_with_slash_command?(current_user, last_diff_sha: last_diff_sha)
+
+      merge_request.update(merge_error: nil)
+
+      if merge_request.head_pipeline && merge_request.head_pipeline.active?
+        MergeRequests::MergeWhenPipelineSucceedsService.new(project, current_user).execute(merge_request)
+      else
+        MergeWorker.perform_async(merge_request.id, current_user.id, {})
+      end
+    end
+
     def reopen_service
       MergeRequests::ReopenService
     end
diff --git a/app/services/notes/create_service.rb b/app/services/notes/create_service.rb
index 1beca9f4109..cdd765c85eb 100644
--- a/app/services/notes/create_service.rb
+++ b/app/services/notes/create_service.rb
@@ -1,6 +1,8 @@
 module Notes
   class CreateService < BaseService
     def execute
+      merge_request_diff_head_sha = params.delete(:merge_request_diff_head_sha)
+
       note = project.notes.new(params)
       note.author = current_user
       note.system = false
@@ -19,7 +21,8 @@ module Notes
       slash_commands_service = SlashCommandsService.new(project, current_user)
 
       if slash_commands_service.supported?(note)
-        content, command_params = slash_commands_service.extract_commands(note)
+        options = { merge_request_diff_head_sha: merge_request_diff_head_sha }
+        content, command_params = slash_commands_service.extract_commands(note, options)
 
         only_commands = content.empty?
 
diff --git a/app/services/notes/slash_commands_service.rb b/app/services/notes/slash_commands_service.rb
index 2edbd39a9e7..aaea9717fc4 100644
--- a/app/services/notes/slash_commands_service.rb
+++ b/app/services/notes/slash_commands_service.rb
@@ -19,10 +19,10 @@ module Notes
       self.class.supported?(note, current_user)
     end
 
-    def extract_commands(note)
+    def extract_commands(note, options = {})
       return [note.note, {}] unless supported?(note)
 
-      SlashCommands::InterpretService.new(project, current_user).
+      SlashCommands::InterpretService.new(project, current_user, options).
         execute(note.note, note.noteable)
     end
 
diff --git a/app/services/slash_commands/interpret_service.rb b/app/services/slash_commands/interpret_service.rb
index d75c5b1800e..14fad3ba120 100644
--- a/app/services/slash_commands/interpret_service.rb
+++ b/app/services/slash_commands/interpret_service.rb
@@ -2,7 +2,7 @@ module SlashCommands
   class InterpretService < BaseService
     include Gitlab::SlashCommands::Dsl
 
-    attr_reader :issuable
+    attr_reader :issuable, :options
 
     # Takes a text and interprets the commands that are extracted from it.
     # Returns the content without commands, and hash of changes to be applied to a record.
@@ -13,7 +13,8 @@ module SlashCommands
       opts = {
         issuable:     issuable,
         current_user: current_user,
-        project:      project
+        project:      project,
+        params:       params
       }
 
       content, commands = extractor.extract_commands(content, opts)
@@ -58,6 +59,17 @@ module SlashCommands
       @updates[:state_event] = 'reopen'
     end
 
+    desc 'Merge (when build succeeds)'
+    condition do
+      last_diff_sha = params.to_h[:merge_request_diff_head_sha]
+      issuable.is_a?(MergeRequest) &&
+        issuable.mergeable_with_slash_command?(current_user, autocomplete_precheck: !last_diff_sha, last_diff_sha: last_diff_sha) &&
+        issuable.persisted?
+    end
+    command :merge do
+      @updates[:merge] = params[:merge_request_diff_head_sha]
+    end
+
     desc 'Change title'
     params '<New title>'
     condition do
diff --git a/app/views/projects/notes/_form.html.haml b/app/views/projects/notes/_form.html.haml
index 39731668a61..b561052e721 100644
--- a/app/views/projects/notes/_form.html.haml
+++ b/app/views/projects/notes/_form.html.haml
@@ -3,6 +3,7 @@
 = form_for [@project.namespace.becomes(Namespace), @project, @note], remote: true, html: { :'data-type' => 'json', multipart: true, id: nil, class: "new-note js-new-note-form js-quick-submit common-note-form", "data-noteable-iid" => @note.noteable.try(:iid), }, authenticity_token: true do |f|
   = hidden_field_tag :view, diff_view
   = hidden_field_tag :line_type
+  = hidden_field_tag :merge_request_diff_head_sha, @note.noteable.try(:diff_head_sha)
   = note_target_fields(@note)
   = f.hidden_field :commit_id
   = f.hidden_field :line_code