Allow the /merge quick action through graphql create note

Issue: gitlab.com/gitlab-org/gitlab/-/issues/354091
MR: gitlab.com/gitlab-org/gitlab/-/merge_requests/82248

Changelog: added

app/graphql/mutations/notes/base.rb

@@ -3,6 +3,12 @@
 module Mutations
   module Notes
     class Base < BaseMutation
+      QUICK_ACTION_ONLY_WARNING = <<~NB
+        If the body of the Note contains only quick actions,
+        the Note will be destroyed during an update, and no Note will be
+        returned.
+      NB
+
       field :note,
             Types::Notes::NoteType,
             null: true,

app/graphql/mutations/notes/create/note.rb

@@ -5,12 +5,18 @@ module Mutations
     module Create
       class Note < Base
         graphql_name 'CreateNote'
+        description "Creates a Note.\n#{QUICK_ACTION_ONLY_WARNING}"
 
         argument :discussion_id,
                   ::Types::GlobalIDType[::Discussion],
                   required: false,
                   description: 'Global ID of the discussion this note is in reply to.'
 
+        argument :merge_request_diff_head_sha,
+                  GraphQL::Types::String,
+                  required: false,
+                  description: 'SHA of the head commit which is used to ensure that the merge request has not been updated since the request was sent.'
+
         private
 
         def create_note_params(noteable, args)
@@ -28,7 +34,8 @@ module Mutations
           end
 
           super(noteable, args).merge({
-            in_reply_to_discussion_id: discussion_id
+            in_reply_to_discussion_id: discussion_id,
+            merge_request_diff_head_sha: args[:merge_request_diff_head_sha]
           })
         end
 

app/graphql/mutations/notes/update/base.rb

@@ -6,12 +6,6 @@ module Mutations
       # This is a Base class for the Note update mutations and is not
       # mounted as a GraphQL mutation itself.
       class Base < Mutations::Notes::Base
-        QUICK_ACTION_ONLY_WARNING = <<~NB
-          If the body of the Note contains only quick actions,
-          the Note will be destroyed during the update, and no Note will be
-          returned.
-        NB
-
         authorize :admin_note
 
         argument :id,

doc/api/graphql/reference/index.md

@@ -1485,6 +1485,11 @@ Input type: `CreateIterationInput`
 
 ### `Mutation.createNote`
 
+Creates a Note.
+If the body of the Note contains only quick actions,
+the Note will be destroyed during an update, and no Note will be
+returned.
+
 Input type: `CreateNoteInput`
 
 #### Arguments
@@ -1495,6 +1500,7 @@ Input type: `CreateNoteInput`
 | <a id="mutationcreatenoteclientmutationid"></a>`clientMutationId` | [`String`](#string) | A unique identifier for the client performing the mutation. |
 | <a id="mutationcreatenoteconfidential"></a>`confidential` | [`Boolean`](#boolean) | Confidentiality flag of a note. Default is false. |
 | <a id="mutationcreatenotediscussionid"></a>`discussionId` | [`DiscussionID`](#discussionid) | Global ID of the discussion this note is in reply to. |
+| <a id="mutationcreatenotemergerequestdiffheadsha"></a>`mergeRequestDiffHeadSha` | [`String`](#string) | SHA of the head commit which is used to ensure that the merge request has not been updated since the request was sent. |
 | <a id="mutationcreatenotenoteableid"></a>`noteableId` | [`NoteableID!`](#noteableid) | Global ID of the resource to add a note to. |
 
 #### Fields
@@ -4811,7 +4817,7 @@ Input type: `UpdateEpicBoardListInput`
 
 Updates a DiffNote on an image (a `Note` where the `position.positionType` is `"image"`).
 If the body of the Note contains only quick actions,
-the Note will be destroyed during the update, and no Note will be
+the Note will be destroyed during an update, and no Note will be
 returned.
 
 Input type: `UpdateImageDiffNoteInput`
@@ -4918,7 +4924,7 @@ Input type: `UpdateNamespacePackageSettingsInput`
 
 Updates a Note.
 If the body of the Note contains only quick actions,
-the Note will be destroyed during the update, and no Note will be
+the Note will be destroyed during an update, and no Note will be
 returned.
 
 Input type: `UpdateNoteInput`

spec/requests/api/graphql/mutations/notes/create/note_spec.rb

@@ -8,13 +8,16 @@ RSpec.describe 'Adding a Note' do
   let_it_be(:current_user) { create(:user) }
 
   let(:noteable) { create(:merge_request, source_project: project, target_project: project) }
-  let(:project) { create(:project) }
+  let(:project) { create(:project, :repository) }
   let(:discussion) { nil }
+  let(:head_sha) { nil }
+  let(:body) { 'Body text' }
   let(:mutation) do
     variables = {
       noteable_id: GitlabSchema.id_from_object(noteable).to_s,
       discussion_id: (GitlabSchema.id_from_object(discussion).to_s if discussion),
-      body: 'Body text',
+      merge_request_diff_head_sha: head_sha.presence,
+      body: body,
       confidential: true
     }
 
@@ -54,7 +57,7 @@ RSpec.describe 'Adding a Note' do
         let(:discussion) { create(:discussion_note).to_discussion }
 
         it_behaves_like 'a mutation that returns top-level errors',
-                  errors: ["The discussion does not exist or you don't have permission to perform this action"]
+          errors: ["The discussion does not exist or you don't have permission to perform this action"]
       end
 
       context 'when the user has permission to create notes on the discussion' do
@@ -75,5 +78,29 @@ RSpec.describe 'Adding a Note' do
         end
       end
     end
+
+    context 'when body only contains quick actions' do
+      let(:head_sha) { noteable.diff_head_sha }
+      let(:body) { '/merge' }
+
+      before do
+        project.add_developer(current_user)
+      end
+
+      # NOTE: Known issue https://gitlab.com/gitlab-org/gitlab/-/issues/346557
+      it 'returns a nil note and info about the command in errors' do
+        post_graphql_mutation(mutation, current_user: current_user)
+
+        expect(mutation_response).to include(
+          'errors' => [/Merged this merge request/],
+          'note' => nil
+        )
+      end
+
+      it 'starts the merge process' do
+        expect { post_graphql_mutation(mutation, current_user: current_user) }
+          .to change { noteable.reload.merge_jid.present? }.from(false).to(true)
+      end
+    end
   end
 end