[PATCH] vi: correctly detect when a deletion empties the buffer

[Denys Vlasenko]

Applied, thanks!
On Fri, Nov 30, 2018 at 6:41 PM Ron Yorston <rmy at pobox.com> wrote:
>
> Michał Berger has reported two issues:
>
> - Repeatedly deleting and undoing the deletion of the last line
>   results in characters being lost from the end of the line.
>
> - Deleting the bottom line twice then attempting to undo each of
>   these deletions results in a segfault.
>
> The problem seems to be an incorrect test for whether the text buffer
> is empty.
>
> Reported-by: Michał Berger <michallinuxstuff at gmail.com>
> Signed-off-by: Ron Yorston <rmy at pobox.com>
> ---
>  editors/vi.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/editors/vi.c b/editors/vi.c
> index ee3c7feb2..271529404 100644
> --- a/editors/vi.c
> +++ b/editors/vi.c
> @@ -2364,7 +2364,7 @@ static void undo_push(char *src, unsigned int length, uint8_t u_type)     // Add to
>         // Allocate a new undo object
>         if (u_type == UNDO_DEL || u_type == UNDO_DEL_CHAIN) {
>                 // For UNDO_DEL objects, save deleted text
> -               if ((src + length) == end)
> +               if ((text + length) == end)
>                         length--;
>                 // If this deletion empties text[], strip the newline. When the buffer becomes
>                 // zero-length, a newline is added back, which requires this to compensate.
> --
> 2.19.2
>
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