autocomplete: fix autocomplete triggering after blank space.

app/javascript/src/javascripts/autocomplete.js.erb

@@ -98,11 +98,6 @@ Autocomplete.initialize_tag_autocomplete = function() {
       var metatag = query.metatag;
       var term = query.term;
 
-      if (!metatag && !term) {
-        this.close();
-        return;
-      }
-
       switch (metatag) {
       case "order":
       case "status":
@@ -244,6 +239,11 @@ Autocomplete.initialize_wiki_autocomplete = function($fields) {
 };
 
 Autocomplete.normal_source = function(term, resp) {
+  if (term === "") {
+    resp([]);
+    return;
+  }
+
   return $.ajax({
     url: "/tags/autocomplete.json",
     data: {

test/system/autocomplete_test.rb

@@ -8,6 +8,7 @@ class AutocompleteTest < ApplicationSystemTestCase
 
   def assert_autocomplete_equals(expected_results, text, id:)
     autocomplete(id, text)
+    sleep 1 if expected_results.empty?
 
     assert_selector 'ul.ui-autocomplete li', count: expected_results.size
     expected_results.each do |result|
@@ -102,6 +103,11 @@ class AutocompleteTest < ApplicationSystemTestCase
         assert_search_autocomplete_equals([], "one two")
       end
 
+      should "not complete tags after a space" do
+        create(:tag, name: "bkub", post_count: 42)
+        assert_search_autocomplete_equals([], "bkub ")
+      end
+
       should "correct invalid operator combinations" do
         create(:tag, name: "bkub", post_count: 42)