Merge branch 'ph/282476/fixGraphQLDiffComments' into 'master'

Fixes createDiffNote GraphQL mutation

See merge request gitlab-org/gitlab!54801

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

@@ -11,6 +11,22 @@ module Mutations
                   required: true,
                   description: copy_field_description(Types::Notes::NoteType, :position)
 
+        def ready?(**args)
+          # As both arguments are optional, validate here that one of the
+          # arguments are present.
+          #
+          # This may be able to be done using InputUnions in the future
+          # if this RFC is merged:
+          # https://github.com/graphql/graphql-spec/blob/master/rfcs/InputUnion.md
+
+          if args[:position].to_hash.values_at(:old_line, :new_line).compact.blank?
+            raise Gitlab::Graphql::Errors::ArgumentError,
+                  'position oldLine or newLine arguments are required'
+          end
+
+          super(**args)
+        end
+
         private
 
         def create_note_params(noteable, args)

app/graphql/types/notes/diff_position_input_type.rb

@@ -8,7 +8,7 @@ module Types
 
       argument :old_line, GraphQL::INT_TYPE, required: false,
                description: copy_field_description(Types::Notes::DiffPositionType, :old_line)
-      argument :new_line, GraphQL::INT_TYPE, required: true,
+      argument :new_line, GraphQL::INT_TYPE, required: false,
                description: copy_field_description(Types::Notes::DiffPositionType, :new_line)
     end
     # rubocop: enable Graphql/AuthorizeTypes

changelogs/unreleased/ph-282476-fixGraphQLDiffComments.yml

+---
+title: Fixed diff notes GraphQL mutation not allowing comments on deleted lines
+merge_request: 54801
+author:
+type: fixed

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

@@ -9,8 +9,9 @@ RSpec.describe 'Adding a DiffNote' do
   let(:noteable) { create(:merge_request, source_project: project, target_project: project) }
   let(:project) { create(:project, :repository) }
   let(:diff_refs) { noteable.diff_refs }
-  let(:mutation) do
-    variables = {
+
+  let(:base_variables) do
+    {
       noteable_id: GitlabSchema.id_from_object(noteable).to_s,
       body: 'Body text',
       position: {
@@ -18,16 +19,16 @@ RSpec.describe 'Adding a DiffNote' do
           old_path: 'files/ruby/popen.rb',
           new_path: 'files/ruby/popen2.rb'
         },
-        new_line: 14,
         base_sha: diff_refs.base_sha,
         head_sha: diff_refs.head_sha,
         start_sha: diff_refs.start_sha
       }
     }
-
-    graphql_mutation(:create_diff_note, variables)
   end
 
+  let(:variables) { base_variables.deep_merge({ position: { new_line: 14 } }) }
+  let(:mutation) { graphql_mutation(:create_diff_note, variables) }
+
   def mutation_response
     graphql_mutation_response(:create_diff_note)
   end
@@ -41,6 +42,18 @@ RSpec.describe 'Adding a DiffNote' do
 
     it_behaves_like 'a Note mutation that creates a Note'
 
+    context 'add comment to old line' do
+      let(:variables) { base_variables.deep_merge({ position: { old_line: 14 } }) }
+
+      it_behaves_like 'a Note mutation that creates a Note'
+    end
+
+    context 'add a comment with a position without lines' do
+      let(:variables) { base_variables }
+
+      it_behaves_like 'a Note mutation that does not create a Note'
+    end
+
     it_behaves_like 'a Note mutation when there are active record validation errors', model: DiffNote
 
     it_behaves_like 'a Note mutation when there are rate limit validation errors'