Revert "Add #closed_without_source_project?"

This reverts commit 31c37c6c.

See #23341

app/models/merge_request.rb

@@ -333,11 +333,7 @@ class MergeRequest < ActiveRecord::Base
   end
   def closed_without_fork?
-    closed? && forked_source_project_missing?
-  end
-
-  def closed_without_source_project?
-    closed? && !source_project
+    closed? && (forked_source_project_missing? || !source_project)
   end
   def forked_source_project_missing?
@@ -348,9 +344,7 @@ class MergeRequest < ActiveRecord::Base
   end
   def reopenable?
-    return false if closed_without_fork? || closed_without_source_project? || merged?
-
-    closed?
+    source_branch_exists? && closed?
   end
   def ensure_merge_request_diff

app/views/projects/merge_requests/_show.html.haml

@@ -26,7 +26,6 @@
             %ul.dropdown-menu.dropdown-menu-align-right
               %li= link_to "Email Patches", merge_request_path(@merge_request, format: :patch)
               %li= link_to "Plain Diff",    merge_request_path(@merge_request, format: :diff)
-      - unless @merge_request.closed_without_fork?
       .normal
         %span Request to merge
         %span.label-branch= source_branch_with_namespace(@merge_request)
@@ -36,7 +35,6 @@
         - if @merge_request.open? && @merge_request.diverged_from_target_branch?
           %span (#{pluralize(@merge_request.diverged_commits_count, 'commit')} behind)
-    - unless @merge_request.closed_without_source_project?
     = render "projects/merge_requests/show/how_to_merge"
     = render "projects/merge_requests/widget/show.html.haml"
@@ -52,7 +50,6 @@
           = link_to namespace_project_merge_request_path(@project.namespace, @project, @merge_request), data: { target: 'div#notes', action: 'notes', toggle: 'tab' } do
             Discussion
             %span.badge= @merge_request.mr_and_commit_notes.user.count
-        - unless @merge_request.closed_without_source_project?
         %li.commits-tab
           = link_to commits_namespace_project_merge_request_path(@project.namespace, @project, @merge_request), data: { target: 'div#commits', action: 'commits', toggle: 'tab' } do
             Commits

spec/models/merge_request_spec.rb

@@ -1274,38 +1274,6 @@ describe MergeRequest, models: true do
     end
   end
-  describe '#closed_without_source_project?' do
-    let(:project)      { create(:project) }
-    let(:user)         { create(:user) }
-    let(:fork_project) { create(:project, forked_from_project: project, namespace: user.namespace) }
-    let(:destroy_service) { Projects::DestroyService.new(fork_project, user) }
-
-    context 'when the merge request is closed' do
-      let(:closed_merge_request) do
-        create(:closed_merge_request,
-          source_project: fork_project,
-          target_project: project)
-      end
-
-      it 'returns false if the source project exists' do
-        expect(closed_merge_request.closed_without_source_project?).to be_falsey
-      end
-
-      it 'returns true if the source project does not exist' do
-        destroy_service.execute
-        closed_merge_request.reload
-
-        expect(closed_merge_request.closed_without_source_project?).to be_truthy
-      end
-    end
-
-    context 'when the merge request is open' do
-      it 'returns false' do
-        expect(subject.closed_without_source_project?).to be_falsey
-      end
-    end
-  end
-
   describe '#reopenable?' do
     context 'when the merge request is closed' do
       it 'returns true' do