Disable rebase until merge request has been approved.

app/views/projects/merge_requests/widget/open/_rebase.html.haml

 - content_for :page_specific_javascripts do
   = page_specific_javascript_tag('merge_request_widget/ci_bundle.js')
 
+- approval_pending = @merge_request.requires_approve? && !@merge_request.approved?
+
 - if @merge_request.rebase_in_progress? || (defined?(rebase_in_progress) && rebase_in_progress)
   %h4.rebase-in-progress
     = icon("spinner spin")
@@ -21,7 +23,9 @@
     = hidden_field_tag :authenticity_token, form_authenticity_token
     .accept-merge-holder.clearfix.js-toggle-container
       .accept-action
-        = f.button class: "btn btn-reopen js-rebase-button" do
+        = f.button class: "btn btn-reopen js-rebase-button", disabled: approval_pending, ":disabled" => "disableAcceptance" do
           Rebase onto #{@merge_request.target_branch}
       .accept-control
         Fast-forward merge is not possible. Rebase the source branch onto the target branch or merge target branch into source branch to allow this merge request to be merged.
+        - if @merge_request.requires_approve?
+          %b{ "v-show" => "disableAcceptance" } (Rebasing is disabled until merge request has been approved)

spec/features/merge_requests/approvals_spec.rb

@@ -256,6 +256,32 @@ feature 'Merge request approvals', js: true, feature: true do
         expect(page).to have_button('Merge When Pipeline Succeeds', disabled: true)
       end
     end
+
+    context 'when rebase is needed but no approval given', js: true do
+      let(:project) do
+        create(:project,
+          approvals_before_merge: 1,
+          merge_requests_rebase_enabled: true,
+          merge_requests_ff_only_enabled: true )
+      end
+
+      let(:merge_request) { create(:merge_request, source_project: project, source_branch: 'feature', target_branch: 'wip' ) }
+
+      before do
+        create :approver_group, group: group, target: merge_request
+        visit namespace_project_merge_request_path(project.namespace, project, merge_request)
+      end
+
+      it 'I am unable to rebase the merge request' do
+        # before approval status is loaded
+        expect(page).to have_button('Rebase onto wip', disabled: true)
+
+        wait_for_ajax
+
+        # after approval status is loaded
+        expect(page).to have_button('Rebase onto wip', disabled: true)
+      end
+    end
   end
 end