Re: [PATCH 1/2] gdb: use gdb::unique_xmalloc_ptr<char> for docs in cmdpy_init

[Andrew Burgess <aburgess@redhat.com>]

Tom Tromey <tom@tromey.com> writes:

>>>>>> "Andrew" == Andrew Burgess via Gdb-patches <gdb-patches@sourceware.org> writes:
>
> Andrew> Make use of gdb::unique_xmalloc_ptr<char> to hold the documentation
> Andrew> string in cmdpy_init (when creating a custom GDB command in Python).
> Andrew> I think this is all pretty straight forward, the only slight weirdness
> Andrew> is the removal of the call to free toward the end of this function.
>
> Andrew> Prior to this commit, if an exception was thrown after the GDB command
> Andrew> was created then we would (I think) end up freeing the documentation
> Andrew> string even though the command would remain registered with GDB, which
> Andrew> would surely lead to undefined behaviour.
>
> Andrew> After this commit we release the doc string at the point that we hand
> Andrew> it over to the command creation routines.  If we throw _after_ the
> Andrew> command has been created within GDB then the doc string will be left
> Andrew> live.  If we throw during the command creation itself (either from
> Andrew> add_prefix_cmd or add_cmd) then it is up to those functions to free
> Andrew> the doc string (I suspect we don't, but I think in general the
> Andrew> commands are pretty bad at cleaning up after themselves, so I don't
> Andrew> think this is a huge problem).
>
> This looks ok to me.
> Maybe an add_prefix_cmd overload that takes a unique_xmalloc_ptr would
> be the way to go eventually.

I agree being able to pass a unique_xmalloc_ptr to the commands would
improve things.

That said, I've pushed this patch as is for now, as I feel improving the
memory management for cmds is a bigger, separate, task.

Thanks,
Andrew