Merge pull request #21432 from yui-knk/fix/what_change_method_can_reverse

[ci skip] Update what methods `Migration#change` can reverse

activerecord/lib/active_record/migration/command_recorder.rb

@@ -5,10 +5,22 @@ class Migration
     # knows how to invert the following commands:
     #
     # * add_column
+    # * add_foreign_key
     # * add_index
+    # * add_reference
     # * add_timestamps
-    # * create_table
+    # * change_column_default (must supply a :from and :to option)
+    # * change_column_null
     # * create_join_table
+    # * create_table
+    # * disable_extension
+    # * drop_join_table
+    # * drop_table (must supply a block)
+    # * enable_extension
+    # * remove_column (must supply a type)
+    # * remove_foreign_key (must supply a second table)
+    # * remove_index
+    # * remove_reference
     # * remove_timestamps
     # * rename_column
     # * rename_index

guides/source/active_record_migrations.md

@@ -522,20 +522,27 @@ majority of cases, where Active Record knows how to reverse the migration
 automatically. Currently, the `change` method supports only these migration
 definitions:
 
-* `add_column`
-* `add_index`
-* `add_reference`
-* `add_timestamps`
-* `add_foreign_key`
-* `create_table`
-* `create_join_table`
-* `drop_table` (must supply a block)
-* `drop_join_table` (must supply a block)
-* `remove_timestamps`
-* `rename_column`
-* `rename_index`
-* `remove_reference`
-* `rename_table`
+* add_column
+* add_foreign_key
+* add_index
+* add_reference
+* add_timestamps
+* change_column_default (must supply a :from and :to option)
+* change_column_null
+* create_join_table
+* create_table
+* disable_extension
+* drop_join_table
+* drop_table (must supply a block)
+* enable_extension
+* remove_column (must supply a type)
+* remove_foreign_key (must supply a second table)
+* remove_index
+* remove_reference
+* remove_timestamps
+* rename_column
+* rename_index
+* rename_table
 
 `change_table` is also reversible, as long as the block does not call `change`,
 `change_default` or `remove`.