Add `web_url` to branch API response

* Add test for API::Entities::Branch
* Add `web_url` example to API documentation
* Update schema for branches endpoint
* Add Changelog entry

changelogs/unreleased/214547_expose_web_url.yml

+---
+title: Add `web_url` to branch API response
+merge_request: 30147
+author:
+type: added

doc/api/branches.md

@@ -41,6 +41,7 @@ Example response:
     "developers_can_push": false,
     "developers_can_merge": false,
     "can_push": true,
+    "web_url": "http://gitlab.example.com/my-group/my-project/-/tree/master",
     "commit": {
       "author_email": "john@example.com",
       "author_name": "John Smith",
@@ -96,6 +97,7 @@ Example response:
   "developers_can_push": false,
   "developers_can_merge": false,
   "can_push": true,
+  "web_url": "http://gitlab.example.com/my-group/my-project/-/tree/master",
   "commit": {
     "author_email": "john@example.com",
     "author_name": "John Smith",
@@ -171,7 +173,8 @@ Example response:
   "default": false,
   "developers_can_push": false,
   "developers_can_merge": false,
-  "can_push": true
+  "can_push": true,
+  "web_url": "http://gitlab.example.com/my-group/my-project/-/tree/newbranch"
 }
 ```
 

lib/api/entities/branch.rb

@@ -3,6 +3,8 @@
 module API
   module Entities
     class Branch < Grape::Entity
+      include Gitlab::Routing
+
       expose :name
 
       expose :commit, using: Entities::Commit do |repo_branch, options|
@@ -36,6 +38,10 @@ module API
       expose :default do |repo_branch, options|
         options[:project].default_branch == repo_branch.name
       end
+
+      expose :web_url do |repo_branch|
+        project_tree_url(options[:project], repo_branch.name)
+      end
     end
   end
 end

spec/fixtures/api/schemas/public_api/v4/branch.json

@@ -7,7 +7,8 @@
     "protected",
     "default",
     "developers_can_push",
-    "developers_can_merge"
+    "developers_can_merge",
+    "web_url"
   ],
   "properties" : {
     "name": { "type": "string" },
@@ -17,7 +18,8 @@
     "default": { "type": "boolean" },
     "developers_can_push": { "type": "boolean" },
     "developers_can_merge": { "type": "boolean" },
-    "can_push": { "type": "boolean" }
+    "can_push": { "type": "boolean" },
+    "web_url": { "type": "uri" }
   },
   "additionalProperties": false
 }

spec/lib/api/entities/branch_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+describe API::Entities::Branch do
+  describe '#as_json' do
+    subject { entity.as_json }
+
+    let(:project) { create(:project, :public, :repository) }
+    let(:repository) { project.repository }
+    let(:branch) { repository.find_branch('master') }
+    let(:entity) { described_class.new(branch, project: project) }
+
+    it 'includes basic fields', :aggregate_failures do
+      is_expected.to include(
+        name: 'master',
+        commit: a_kind_of(Hash),
+        merged: false,
+        protected: false,
+        developers_can_push: false,
+        developers_can_merge: false,
+        can_push: false,
+        default: true,
+        web_url: Gitlab::Routing.url_helpers.project_tree_url(project, 'master')
+      )
+    end
+  end
+end