From: Matt Hunter <m@lfurio.us>
Date: Sun, 05 Jul 2026 22:23:52 GMT
Subject: Re: [PATCH] rebase -i: introduce `pick -x` to add "cherry picked from commit ..."
Message-ID: <DJQZMN6UIPBY.Z6WBNUP1E3U2@lfurio.us>
In-Reply-To: <xmqqldbpclhh.fsf@gitster.g>

On Sun Jul 5, 2026 at 2:58 PM EDT, Junio C Hamano wrote:
> Trevor Gross <tg@trevorgross.com> writes:
>> @@ -5524,7 +5533,7 @@ static int single_pick(struct repository *r,
>>  		       struct replay_opts *opts)
>>  {
>>  	int check_todo;
>> -	struct todo_item item;
>> +	struct todo_item item = { 0 };
>
> This may be a good change, but I do not think the proposed commit log
> message touched upon it.  It should.  Is it a bug that we somehow were
> lucky that nobody made an access to uninitialized piece of memory here?

On a first glance, do_pick_commit() was only referencing the 'command'
and 'commit' fields of struct todo_item.  Trevor added a reference to
item->flags which created the need to initialize it here.

However, on a second glance, there _is_ a pre-existing reference to
item->flags in do_pick_commit() as well, at line 2410 on master
(e9019fcafe00):

    if (command == TODO_REWORD)
        reword = 1;
    else if (is_fixup(command)) {
        if (update_squash_messages(r, command, commit,
                       opts, item->flags)) {
            res = -1;
            goto leave;
        }

It doesn't look like this code is actually reachable from single_pick()
as written, since it is guarded by is_fixup(command) and single_pick()
doesn't set such a command.