bug#3863: 23.1.50; possible save-match-data in copyright.el

[Lennart Borgman <lennart.borgman@gmail.com>]

On Fri, Jul 17, 2009 at 5:23 AM, Stefan Monnier<monnier@iro.umontreal.ca> wrote:
>> I don't think I understand, but it sounds like this is a reason why
>> y-or-n-p should save match-data...
>
> Here we go again:
>
> All functions destroy the match-data except for a few rare exceptions,
> which are simple functions doing little work.
>
>> Is there any reason not to let y-or-n-p save match data?
>
> If you think y-or-n-p deserves saving the match-data then pretty much
> all other functions deserve that change as well.  And since
> save-match-data is somewhat costly, it would imply a singificant
> performance impact.

Sorry, I just meant that since the functions that prompts the user
can't really impact performance if we just add save-match-data to them
we could do that just to get some more protection.

It does not cure the problem that some functions running in timers
forgets to save match data, but perhaps it catches some actually
occuring problem cases.