Add Expression Indexes and Operator Classes support for PostgreSQL

Example:

    create_table :users do |t|
      t.string :name
      t.index 'lower(name) varchar_pattern_ops'
    end

Fixes #19090.
Fixes #21765.
Fixes #21819.
Fixes #24359.

Signed-off-by: Jeremy Daer <jeremydaer@gmail.com>

1 files changed, 6 insertions, 1 deletions

diff --git a/activerecord/test/cases/schema_dumper_test.rb b/activerecord/test/cases/schema_dumper_test.rb
index 7a304eab7f..f1927f561e 100644
--- a/activerecord/test/cases/schema_dumper_test.rb
+++ b/activerecord/test/cases/schema_dumper_test.rb
@@ -92,7 +92,7 @@ class SchemaDumperTest < ActiveRecord::TestCase
       next if column_set.empty?
 
       lengths = column_set.map do |column|
-        if match = column.match(/\bt\.\w+\s+"/)
+        if match = column.match(/\bt\.\w+\s+(?="\w+?")/)
           match[0].length
         end
       end.compact
@@ -279,6 +279,11 @@ class SchemaDumperTest < ActiveRecord::TestCase
       assert_match %r{t\.decimal\s+"decimal_array_default",\s+default: \["1.23", "3.45"\],\s+array: true}, output
     end
 
+    def test_schema_dump_expression_indices
+      index_definition = standard_dump.split(/\n/).grep(/t\.index.*company_expression_index/).first.strip
+      assert_equal 't.index "lower((name)::text)", name: "company_expression_index", using: :btree', index_definition
+    end
+
     if ActiveRecord::Base.connection.supports_extensions?
       def test_schema_dump_includes_extensions
         connection = ActiveRecord::Base.connection