FIX: tag input doesn't show all top 5 permitted tags

app/controllers/tags_controller.rb

@@ -216,7 +216,7 @@ class TagsController < ::ApplicationController
       filter_params[:term] = clean_name
       filter_params[:order_search_results] = true
     else
-      filter_params[:order] = "topic_count DESC"
+      filter_params[:order_popularity] = true
     end
 
     tags_with_counts = DiscourseTagging.filter_allowed_tags(

lib/discourse_tagging.rb

@@ -151,7 +151,7 @@ module DiscourseTagging
 
   TAG_GROUP_RESTRICTIONS_SQL ||= <<~SQL
     tag_group_restrictions AS (
-      SELECT t.name as tag_name, t.id as tag_id, tgm.id as tgm_id, tg.id as tag_group_id, tg.parent_tag_id as parent_tag_id,
+      SELECT t.id as tag_id, tgm.id as tgm_id, tg.id as tag_group_id, tg.parent_tag_id as parent_tag_id,
         tg.one_per_topic as one_per_topic
       FROM tags t
       LEFT OUTER JOIN tag_group_memberships tgm ON tgm.tag_id = t.id /*and_name_like*/
@@ -161,13 +161,13 @@ module DiscourseTagging
 
   CATEGORY_RESTRICTIONS_SQL ||= <<~SQL
     category_restrictions AS (
-      SELECT t.name as tag_name, t.id as tag_id, ct.id as ct_id, ct.category_id as category_id
+      SELECT t.id as tag_id, ct.id as ct_id, ct.category_id as category_id
       FROM tags t
       INNER JOIN category_tags ct ON t.id = ct.tag_id /*and_name_like*/
 
       UNION
 
-      SELECT t.name as tag_name, t.id as tag_id, ctg.id as ctg_id, ctg.category_id as category_id
+      SELECT t.id as tag_id, ctg.id as ctg_id, ctg.category_id as category_id
       FROM tags t
       INNER JOIN tag_group_memberships tgm ON tgm.tag_id = t.id /*and_name_like*/
       INNER JOIN category_tag_groups ctg ON tgm.tag_group_id = ctg.tag_group_id
@@ -189,7 +189,6 @@ module DiscourseTagging
 
   # Options:
   #   term: a search term to filter tags by name
-  #   order: order by for the query
   #   limit: max number of results
   #   category: a Category to which the object being tagged belongs
   #   for_input: result is for an input field, so only show permitted tags
@@ -197,6 +196,8 @@ module DiscourseTagging
   #   selected_tags: an array of tag names that are in the current selection
   #   only_tag_names: limit results to tags with these names
   #   exclude_synonyms: exclude synonyms from results
+  #   order_search_results: result should be ordered for name search results
+  #   order_popularity: order result by topic_count
   def self.filter_allowed_tags(guardian, opts = {})
     selected_tag_ids = opts[:selected_tags] ? Tag.where_name(opts[:selected_tags]).pluck(:id) : []
     category = opts[:category]
@@ -219,8 +220,16 @@ module DiscourseTagging
 
     outer_join = category.nil? || category.allow_global_tags || !category_has_restricted_tags
 
+    distinct_clause = if opts[:order_popularity]
+      "DISTINCT ON (topic_count, name)"
+    elsif opts[:order_search_results]
+      "DISTINCT ON (lower(name) = lower(:cleaned_term), topic_count, name)"
+    else
+      ""
+    end
+
     sql << <<~SQL
-      SELECT t.id, t.name, t.topic_count, t.pm_topic_count,
+      SELECT #{distinct_clause} t.id, t.name, t.topic_count, t.pm_topic_count,
         tgr.tgm_id as tgm_id, tgr.tag_group_id as tag_group_id, tgr.parent_tag_id as parent_tag_id,
         tgr.one_per_topic as one_per_topic, t.target_tag_id
       FROM tags t
@@ -323,10 +332,10 @@ module DiscourseTagging
     end
 
     builder.limit(opts[:limit]) if opts[:limit]
-    if opts[:order]
-      builder.order_by(opts[:order])
+    if opts[:order_popularity]
+      builder.order_by("topic_count DESC, name")
     elsif opts[:order_search_results] && !term.blank?
-      builder.order_by("lower(name) = lower(:cleaned_term) DESC, topic_count DESC")
+      builder.order_by("lower(name) = lower(:cleaned_term) DESC, topic_count DESC, name")
     end
 
     result = builder.query(builder_params).uniq { |t| t.id }

spec/requests/tags_controller_spec.rb

@@ -617,6 +617,19 @@ describe TagsController do
         json = get_json_body
         expect(json["results"].map { |j| j["id"] }).to eq(['тема-в-разработке'])
       end
+
+      it "can return all the results" do
+        tag_group1 = Fabricate(:tag_group, tag_names: ['common1', 'common2', 'group1tag', 'group1tag2'])
+        tag_group2 = Fabricate(:tag_group, tag_names: ['common1', 'common2'])
+        category = Fabricate(:category, tag_groups: [tag_group1])
+        get "/tags/filter/search.json", params: { q: '', limit: 5, categoryId: category.id, filterForInput: 'true' }
+        expect(response.status).to eq(200)
+        json = get_json_body
+        expect_same_tag_names(
+          json["results"].map { |j| j["id"] },
+          ['common1', 'common2', 'group1tag', 'group1tag2']
+        )
+      end
     end
   end