Fix tag search ordering

app/models/tag.rb

@@ -18,22 +18,25 @@ class Tag < ApplicationRecord
   validate :synonym_unique
   validates :name, uniqueness: { scope: [:tag_set_id], case_sensitive: false }
 
+  # Fuzzy-searches tags by name, excerpt, and synonym name
+  # @param term [String] search term
+  # @return [ActiveRecord::Relation<Tag>]
   def self.search(term)
-    stripped = term.strip
+    value = "%#{sanitize_sql_like(term.strip)}%"
+
     # Query to search on tags, the name is used for sorting.
-    q1 = where('tags.name LIKE ?', "%#{sanitize_sql_like(stripped)}%")
-         .or(where('tags.excerpt LIKE ?', "%#{sanitize_sql_like(stripped)}%"))
-         .select(Arel.sql('name AS sortname, tags.*'))
+    q1 = where('tags.name LIKE ?', value)
+         .or(where('tags.excerpt LIKE ?', value))
+         .select('tags.*')
 
     # Query to search on synonyms, the synonym name is used for sorting.
-    # The order clause here actually applies to the union of q1 and q2 (so not just q2).
     q2 = joins(:tag_synonyms)
-         .where('tag_synonyms.name LIKE ?', "%#{sanitize_sql_like(stripped)}%")
-         .select(Arel.sql('tag_synonyms.name AS sortname, tags.*'))
-         .order(Arel.sql(sanitize_sql_array(['sortname LIKE ? DESC, sortname', "#{sanitize_sql_like(stripped)}%"])))
+         .where('tag_synonyms.name LIKE ?', value)
+         .select('tags.*')
 
     # Select from the union of the above queries, select only the tag columns such that we can distinct them
     from(Arel.sql("((#{q1.to_sql}) UNION (#{q2.to_sql})) tags"))
+      .order(Arel.sql(sanitize_sql_array(['name LIKE ? DESC, name', value])))
       .select(Tag.column_names.map { |c| "tags.#{c}" })
       .distinct
   end

test/models/tag_test.rb

@@ -6,4 +6,18 @@ class TagTest < ActiveSupport::TestCase
   test 'is community related' do
     assert_community_related(Tag)
   end
+
+  test 'search should correctly order tags' do
+    term = 'us'
+
+    tags = Tag.search(term).to_a
+
+    name_match_sorted = tags.select { |t| t.name.include?(term) }.sort { |a, b| a.name <=> b.name }
+    excerpt_match_sorted = tags.select { |t| t.excerpt&.include?(term) }.sort { |a, b| a.name <=> b.name }
+    sorted_tags = name_match_sorted + excerpt_match_sorted
+
+    sorted_tags.each_with_index do |tag, idx|
+      assert_equal tag.name, tags[idx].name
+    end
+  end
 end