Tweak bigint PK handling

* Don't force PKs on tables that have explicitly opted out
* All integer-like PKs are autoincrement unless they have an explicit
  default

2 files changed, 4 insertions, 6 deletions

diff --git a/activerecord/lib/active_record/connection_adapters/mysql/schema_definitions.rb b/activerecord/lib/active_record/connection_adapters/mysql/schema_definitions.rb
index 0cf40de70f..f1ba0cb708 100644
--- a/activerecord/lib/active_record/connection_adapters/mysql/schema_definitions.rb
+++ b/activerecord/lib/active_record/connection_adapters/mysql/schema_definitions.rb
@@ -3,10 +3,8 @@ module ActiveRecord
     module MySQL
       module ColumnMethods
         def primary_key(name, type = :primary_key, **options)
-          if type == :primary_key && !options.key?(:default)
-            options[:auto_increment] = true
-            options[:limit] = 8
-          end
+          options[:auto_increment] = true if [:primary_key, :integer, :bigint].include?(type) && !options.key?(:default)
+          options[:limit] = 8 if [:primary_key].include?(type)
           super
         end
 
diff --git a/activerecord/lib/active_record/connection_adapters/mysql/schema_dumper.rb b/activerecord/lib/active_record/connection_adapters/mysql/schema_dumper.rb
index 2065816501..d44c35714f 100644
--- a/activerecord/lib/active_record/connection_adapters/mysql/schema_dumper.rb
+++ b/activerecord/lib/active_record/connection_adapters/mysql/schema_dumper.rb
@@ -4,8 +4,8 @@ module ActiveRecord
       module ColumnDumper
         def column_spec_for_primary_key(column)
           spec = super
-          if column.type == :integer && !column.auto_increment?
-            spec[:default] = schema_default(column) || "nil"
+          if [:integer, :bigint].include?(schema_type(column)) && !column.auto_increment?
+            spec[:default] ||= schema_default(column) || "nil"
           end
           spec[:unsigned] = "true" if column.unsigned?
           spec