Add offset and limit parameters to names resolver

Adds offset and limit parameters to branch names resolver to facilitate
efficient use.

Changelog: changed

app/graphql/resolvers/repository_branch_names_resolver.rb

@@ -10,7 +10,24 @@ module Resolvers
       required: true,
       description: 'The pattern to search for branch names by.'
 
-    def resolve(search_pattern:)
+    argument :offset, GraphQL::INT_TYPE,
+      required: true,
+      description: 'The number of branch names to skip.'
+
+    argument :limit, GraphQL::INT_TYPE,
+      required: true,
+      description: 'The number of branch names to return.'
+
+    def resolve(search_pattern:, offset:, limit:)
+      names = branch_names(search_pattern)
+      return unless names
+
+      names.lazy.drop(offset).take(limit) # rubocop:disable CodeReuse/ActiveRecord
+    end
+
+    private
+
+    def branch_names(search_pattern)
       Repositories::BranchNamesFinder.new(object, search: search_pattern).execute
     end
   end

doc/api/graphql/reference/index.md

@@ -11708,6 +11708,8 @@ Returns [`[String!]`](#string).
 
 | Name | Type | Description |
 | ---- | ---- | ----------- |
+| <a id="repositorybranchnameslimit"></a>`limit` | [`Int!`](#int) | The number of branch names to return. |
+| <a id="repositorybranchnamesoffset"></a>`offset` | [`Int!`](#int) | The number of branch names to skip. |
 | <a id="repositorybranchnamessearchpattern"></a>`searchPattern` | [`String!`](#string) | The pattern to search for branch names by. |
 
 ##### `Repository.tree`

spec/graphql/resolvers/repository_branch_names_resolver_spec.rb

@@ -12,11 +12,14 @@ RSpec.describe Resolvers::RepositoryBranchNamesResolver do
       resolve(
         described_class,
         obj: project.repository,
-        args: { search_pattern: pattern },
+        args: { search_pattern: pattern, offset: offset, limit: 1 },
         ctx: { current_user: project.creator }
       )
     end
 
+    context 'with zero offset' do
+      let(:offset) { 0 }
+
       context 'with empty search pattern' do
         let(:pattern) { '' }
 
@@ -26,10 +29,20 @@ RSpec.describe Resolvers::RepositoryBranchNamesResolver do
       end
 
       context 'with a valid search pattern' do
-      let(:pattern) { 'mas*' }
+        let(:pattern) { 'snippet/*' }
 
         it 'returns matching branches' do
-        expect(resolve_branch_names).to match_array(['master'])
+          expect(resolve_branch_names).to contain_exactly('snippet/rename-and-edit-file')
+        end
+      end
+    end
+
+    context 'with offset' do
+      let(:pattern) { 'snippet/*' }
+      let(:offset) { 1 }
+
+      it 'skips first match' do
+        expect(resolve_branch_names).to contain_exactly('snippet/edit-file')
       end
     end
   end