Fix approvers dropdown when creating MR from a fork

The `users_select_tag` helper defaults to using `@project`, which in this case
is the source project, not the target project. Explicitly use the target project
to get the right list of users.

app/views/shared/issuable/_approvals.html.haml

@@ -19,13 +19,13 @@
   .col-sm-10
     - author = issuable.author || current_user
     - skip_users = issuable.all_approvers_including_groups + [author]
-    = users_select_tag("merge_request[approver_ids]", multiple: true, class: 'input-large', email_user: true, skip_users: skip_users)
+    = users_select_tag("merge_request[approver_ids]", multiple: true, class: 'input-large', email_user: true, skip_users: skip_users, project: issuable.target_project)
     .help-block
       This merge request must be approved by these users.
       You can override the project settings by setting your own list of approvers.
 
     - skip_groups = issuable.overall_approver_groups.pluck(:group_id)
-    = groups_select_tag('merge_request[approver_group_ids]', multiple: true, data: { skip_groups: skip_groups, all_available: true }, class: 'input-large')
+    = groups_select_tag('merge_request[approver_group_ids]', multiple: true, data: { skip_groups: skip_groups, all_available: true, project: issuable.target_project }, class: 'input-large')
     .help-block
       This merge request must be approved by members of these groups.
       You can override the project settings by setting your own list of approvers.

changelogs/unreleased-ee/2556-approvers-don-t-appear-when-mr-is-created-from-a-fork.yml

+---
+title: Fix approvers dropdown when creating a merge request from a fork
+merge_request:
+author:

spec/features/merge_requests/approvals_spec.rb

@@ -2,15 +2,15 @@ require 'rails_helper'
 
 feature 'Merge request approvals', js: true, feature: true do
   let(:user) { create(:user) }
-  let(:project) { create(:project, approvals_before_merge: 1) }
+  let(:project) { create(:project, :public, approvals_before_merge: 1) }
 
   context 'when editing an MR with a different author' do
     let(:author) { create(:user) }
     let(:merge_request) { create(:merge_request, author: author, source_project: project) }
 
     before do
-      project.team << [user, :developer]
-      project.team << [author, :developer]
+      project.add_developer(user)
+      project.add_developer(author)
 
       login_as(user)
       visit edit_namespace_project_merge_request_path(project.namespace, project, merge_request)
@@ -27,16 +27,20 @@ feature 'Merge request approvals', js: true, feature: true do
     end
   end
 
-  context 'when creating an MR' do
+  context 'when creating an MR from a fork' do
     let(:other_user) { create(:user) }
     let(:non_member) { create(:user) }
+    let(:forked_project) { create(:project, :public, creator: user) }
 
     before do
-      project.team << [user, :developer]
-      project.team << [other_user, :developer]
+      create(:forked_project_link, forked_to_project: forked_project, forked_from_project: project)
+
+      forked_project.add_developer(nuser)
+      project.add_developer(user)
+      project.add_developer(other_user)
 
       login_as(user)
-      visit new_namespace_project_merge_request_path(project.namespace, project, merge_request: { target_branch: 'master', source_branch: 'feature' })
+      visit new_namespace_project_merge_request_path(forked_project.namespace, forked_project, merge_request: { target_branch: 'master', source_branch: 'feature' })
 
       find('#s2id_merge_request_approver_ids .select2-input').click
     end
@@ -59,8 +63,8 @@ feature 'Merge request approvals', js: true, feature: true do
       let(:other_user) { create(:user) }
 
       before do
-        project.team << [user, :developer]
-        project.team << [other_user, :developer]
+        project.add_developer(user)
+        project.add_developer(other_user)
 
         login_as(user)
       end
@@ -114,7 +118,7 @@ feature 'Merge request approvals', js: true, feature: true do
       let(:merge_request) { create(:merge_request, source_project: project) }
 
       before do
-        project.team << [user, :developer]
+        project.add_developer(user)
 
         login_as(user)
       end
@@ -199,8 +203,7 @@ feature 'Merge request approvals', js: true, feature: true do
     let(:group) { create :group }
 
     before do
-      project.team << [user, :developer]
-
+      project.add_developer(user)
       group.add_developer(other_user)
       group.add_developer(user)
 
@@ -300,7 +303,7 @@ feature 'Merge request approvals', js: true, feature: true do
     end
 
     before do
-      project.team << [user, :developer]
+      project.add_developer(user)
       login_as(user)
 
       visit new_namespace_project_merge_request_path(project.namespace, project, merge_request: { target_branch: 'master', source_branch: 'feature' })