Merge branch '21225-wip-slash-command-for-mrs' into 'master'

Add a /wip slash command to toggle the 'WIP' prefix in the MR title

## Why was this MR needed?

As explained in #21225, it prevents you from having to click through the entire edit form just to mark an MR as WIP.

Closes #21225

See merge request !6259

5 files changed, 52 insertions, 10 deletions

diff --git a/app/controllers/projects/merge_requests_controller.rb b/app/controllers/projects/merge_requests_controller.rb
index 68bb4232f5b..8c8c56228ad 100644
--- a/app/controllers/projects/merge_requests_controller.rb
+++ b/app/controllers/projects/merge_requests_controller.rb
@@ -276,7 +276,7 @@ class Projects::MergeRequestsController < Projects::ApplicationController
   end
 
   def remove_wip
-    MergeRequests::UpdateService.new(project, current_user, title: @merge_request.wipless_title).execute(@merge_request)
+    MergeRequests::UpdateService.new(project, current_user, wip_event: 'unwip').execute(@merge_request)
 
     redirect_to namespace_project_merge_request_path(@project.namespace, @project, @merge_request),
       notice: "The merge request can now be merged."
diff --git a/app/models/merge_request.rb b/app/models/merge_request.rb
index aec555dcec0..a431d46cc9e 100644
--- a/app/models/merge_request.rb
+++ b/app/models/merge_request.rb
@@ -155,6 +155,20 @@ class MergeRequest < ActiveRecord::Base
     where("merge_requests.id IN (#{union.to_sql})")
   end
 
+  WIP_REGEX = /\A\s*(\[WIP\]\s*|WIP:\s*|WIP\s+)+\s*/i.freeze
+
+  def self.work_in_progress?(title)
+    !!(title =~ WIP_REGEX)
+  end
+
+  def self.wipless_title(title)
+    title.sub(WIP_REGEX, "")
+  end
+
+  def self.wip_title(title)
+    work_in_progress?(title) ? title : "WIP: #{title}"
+  end
+
   def to_reference(from_project = nil)
     reference = "#{self.class.reference_prefix}#{iid}"
 
@@ -389,14 +403,16 @@ class MergeRequest < ActiveRecord::Base
     @closed_event ||= target_project.events.where(target_id: self.id, target_type: "MergeRequest", action: Event::CLOSED).last
   end
 
-  WIP_REGEX = /\A\s*(\[WIP\]\s*|WIP:\s*|WIP\s+)+\s*/i.freeze
-
   def work_in_progress?
-    !!(title =~ WIP_REGEX)
+    self.class.work_in_progress?(title)
   end
 
   def wipless_title
-    self.title.sub(WIP_REGEX, "")
+    self.class.wipless_title(self.title)
+  end
+
+  def wip_title
+    self.class.wip_title(self.title)
   end
 
   def mergeable?(skip_ci_check: false)
diff --git a/app/services/merge_requests/base_service.rb b/app/services/merge_requests/base_service.rb
index ba424b09463..d0d155b7ee1 100644
--- a/app/services/merge_requests/base_service.rb
+++ b/app/services/merge_requests/base_service.rb
@@ -5,16 +5,17 @@ module MergeRequests
     end
 
     def create_title_change_note(issuable, old_title)
-      removed_wip = old_title =~ MergeRequest::WIP_REGEX && !issuable.work_in_progress?
-      added_wip = old_title !~ MergeRequest::WIP_REGEX && issuable.work_in_progress?
+      removed_wip = MergeRequest.work_in_progress?(old_title) && !issuable.work_in_progress?
+      added_wip = !MergeRequest.work_in_progress?(old_title) && issuable.work_in_progress?
+      changed_title = MergeRequest.wipless_title(old_title) != issuable.wipless_title
 
       if removed_wip
         SystemNoteService.remove_merge_request_wip(issuable, issuable.project, current_user)
       elsif added_wip
         SystemNoteService.add_merge_request_wip(issuable, issuable.project, current_user)
-      else
-        super
       end
+
+      super if changed_title
     end
 
     def hook_data(merge_request, action, oldrev = nil)
diff --git a/app/services/merge_requests/update_service.rb b/app/services/merge_requests/update_service.rb
index f14f9e4b327..9dbec49d163 100644
--- a/app/services/merge_requests/update_service.rb
+++ b/app/services/merge_requests/update_service.rb
@@ -16,7 +16,7 @@ module MergeRequests
       end
 
       merge_request.merge_params['force_remove_source_branch'] = params.delete(:force_remove_source_branch)
-
+      handle_wip_event(merge_request)
       update(merge_request)
     end
 
@@ -81,5 +81,18 @@ module MergeRequests
     def after_update(issuable)
       issuable.cache_merge_request_closes_issues!(current_user)
     end
+
+    private
+
+    def handle_wip_event(merge_request)
+      if wip_event = params.delete(:wip_event)
+        # We update the title that is provided in the params or we use the mr title
+        title = params[:title] || merge_request.title
+        params[:title] = case wip_event
+                         when 'wip' then MergeRequest.wip_title(title)
+                         when 'unwip' then MergeRequest.wipless_title(title)
+                         end
+      end
+    end
   end
 end
diff --git a/app/services/slash_commands/interpret_service.rb b/app/services/slash_commands/interpret_service.rb
index ffcad5b3a87..1725a30fae5 100644
--- a/app/services/slash_commands/interpret_service.rb
+++ b/app/services/slash_commands/interpret_service.rb
@@ -214,6 +214,18 @@ module SlashCommands
       @updates[:due_date] = nil
     end
 
+    desc do
+      "Toggle the Work In Progress status"
+    end
+    condition do
+      issuable.persisted? &&
+        issuable.respond_to?(:work_in_progress?) &&
+        current_user.can?(:"update_#{issuable.to_ability_name}", issuable)
+    end
+    command :wip do
+      @updates[:wip_event] = issuable.work_in_progress? ? 'unwip' : 'wip'
+    end
+
     # This is a dummy command, so that it appears in the autocomplete commands
     desc 'CC'
     params '@user'