sets limit 191 for schema_migrations#version in mysql2 if the encoding is "utf8mb4"

Please, see rationale in the included CHANGELOG patch.

1 files changed, 26 insertions, 0 deletions

diff --git a/activerecord/test/cases/adapters/mysql2/schema_migrations_test.rb b/activerecord/test/cases/adapters/mysql2/schema_migrations_test.rb
new file mode 100644
index 0000000000..9ecd901eac
--- /dev/null
+++ b/activerecord/test/cases/adapters/mysql2/schema_migrations_test.rb
@@ -0,0 +1,26 @@
+require "cases/helper"
+
+module ActiveRecord
+  module ConnectionAdapters
+    class Mysql2Adapter
+      class SchemaMigrationsTest < ActiveRecord::TestCase
+        def test_initializes_schema_migrations_for_encoding_utf8mb4
+          conn = ActiveRecord::Base.connection
+
+          smtn = ActiveRecord::Migrator.schema_migrations_table_name
+          conn.drop_table(smtn) if conn.table_exists?(smtn)
+
+          config = conn.instance_variable_get(:@config)
+          original_encoding = config[:encoding]
+
+          config[:encoding] = 'utf8mb4'
+          conn.initialize_schema_migrations_table
+
+          assert conn.column_exists?(smtn, :version, :string, limit: Mysql2Adapter::MAX_INDEX_LENGTH_FOR_UTF8MB4)
+        ensure
+          config[:encoding] = original_encoding
+        end
+      end
+    end
+  end
+end