Fixes #14638.

The SQL query was ambiguous and in this case we want to filter projects.

CHANGELOG

@@ -22,6 +22,7 @@ v 8.7.0 (unreleased)
   - Fall back to `In-Reply-To` and `References` headers when sub-addressing is not available (David Padilla)
   - Remove "Congratulations!" tweet button on newly-created project. (Connor Shea)
   - Improved UX of the navigation sidebar
+  - Fix admin/projects when using visibility levels on search (PotHix)
   - Build status notifications
   - API: Ability to retrieve a specific tag (Robert Schilling)
   - API: Expose user location (Robert Schilling)

app/controllers/admin/projects_controller.rb

@@ -5,7 +5,7 @@ class Admin::ProjectsController < Admin::ApplicationController
   def index
     @projects = Project.all
     @projects = @projects.in_namespace(params[:namespace_id]) if params[:namespace_id].present?
-    @projects = @projects.where("visibility_level IN (?)", params[:visibility_levels]) if params[:visibility_levels].present?
+    @projects = @projects.where("projects.visibility_level IN (?)", params[:visibility_levels]) if params[:visibility_levels].present?
     @projects = @projects.with_push if params[:with_push].present?
     @projects = @projects.abandoned if params[:abandoned].present?
     @projects = @projects.non_archived unless params[:with_archived].present?

spec/controllers/admin/projects_controller_spec.rb

@@ -0,0 +1,23 @@
+require 'spec_helper'
+
+describe Admin::ProjectsController do
+  let!(:project) { create(:project, visibility_level: Gitlab::VisibilityLevel::PUBLIC) }
+
+  before do
+    sign_in(create(:admin))
+  end
+
+  describe 'GET /projects' do
+    render_views
+
+    it 'retrieves the project for the given visibility level' do
+      get :index, visibility_levels: [Gitlab::VisibilityLevel::PUBLIC]
+      expect(response.body).to match(project.name)
+    end
+
+    it 'does not retrieve the project' do
+      get :index, visibility_levels: [Gitlab::VisibilityLevel::INTERNAL]
+      expect(response.body).to_not match(project.name)
+    end
+  end
+end