Defer has two advantages over try…finally: firstly, it doesn’t introduce a nesting level.
Secondly, if you write
foo
defer revert_foo
, when scanning the code, it’s easier to verify that you didn’t forget the revert_foo part than when there are many lines between foo and the finally block that calls revert_foo.A disadvantage is that defer breaks the “statements are logically executed in source code order” convention. I think that’s more than worth it, though.