Re: [PATCH 2/2] add-patch: update hunk splitability after editing

> From: Phillip Wood <phillip.wood@dunelm.org.uk>
> 
> When the users edits a hunk if they change deletion lines to context
> lines or vice versa then the number of hunks that the edited hunk can be
> split into may differ from the unedited hunk and so we need to update
> hunk->splittable_into. In practice users are unlikely to hit this bug as
> it is doubtful that a user who has edited a hunk will split it
> afterwards.

> 
> Signed-off-by: Phillip Wood <phillip.wood@dunelm.org.uk>
> ---
>  add-patch.c                | 12 +++++++++++-
>  t/t3701-add-interactive.sh | 21 +++++++++++++++++++++
>  2 files changed, 32 insertions(+), 1 deletion(-)
> 
> diff --git a/add-patch.c b/add-patch.c
> index f44f98275cc..982745373df 100644
> --- a/add-patch.c
> +++ b/add-patch.c
> @@ -1182,19 +1182,29 @@ static ssize_t recount_edited_hunk(struct add_p_state *s, struct hunk *hunk,
>  {
>  	struct hunk_header *header = &hunk->header;
>  	size_t i;
> +	char ch, marker = ' ';
>  
> +	hunk->splittable_into = 0;
>  	header->old_count = header->new_count = 0;
>  	for (i = hunk->start; i < hunk->end; ) {
> -		switch(normalize_marker(&s->plain.buf[i])) {
> +		ch = normalize_marker(&s->plain.buf[i]);
> +		switch (ch) {
>  		case '-':
>  			header->old_count++;
> +			if (marker == ' ')
> +				hunk->splittable_into++;
> +			marker = ch;
>  			break;
>  		case '+':
>  			header->new_count++;
> +			if (marker == ' ')
> +				hunk->splittable_into++;
> +			marker = ch;
>  			break;
>  		case ' ':
>  			header->old_count++;
>  			header->new_count++;
> +			marker = ch;
>  			break;
>  		}