For `PostgreSQL >= 9.4` use `gen_random_uuid()`

Since 9.4, PostgreSQL recommends using `pgcrypto`'s `gen_random_uuid()`
to generate version 4 UUIDs instead of the functions in the `uuid-ossp`
extension.

These changes uses the appropriate UUID function depending on the
underlying PostgreSQL server's version, while maintaining
`uuid_generate_v4()` in older migrations.

1 files changed, 8 insertions, 0 deletions

diff --git a/activerecord/lib/active_record/migration/compatibility.rb b/activerecord/lib/active_record/migration/compatibility.rb
index 04e538baa5..ae45ac7157 100644
--- a/activerecord/lib/active_record/migration/compatibility.rb
+++ b/activerecord/lib/active_record/migration/compatibility.rb
@@ -103,6 +103,14 @@ module ActiveRecord
       end
 
       class V5_0 < V5_1
+        def create_table(table_name, options = {})
+          if ActiveRecord::Base.connection.adapter_name == "PostgreSQL"
+            if options[:id] == :uuid && !options[:default]
+              options[:default] = "uuid_generate_v4()"
+            end
+          end
+          super
+        end
       end
 
       class V4_2 < V5_0