Hi Junio, On Fri, 6 Dec 2019, Junio C Hamano wrote: > "Johannes Schindelin via GitGitGadget" <gitgitgadget@xxxxxxxxx> > writes: > > > From: Johannes Schindelin <johannes.schindelin@xxxxxx> > > > > Yes, yes, this is supposed to be only a band-aid option for `git add -p` > > not Doing The Right Thing. But as long as we carry the `--allow-overlap` > > option, we might just as well get it right. > > It probably depends on the definition of "right", where it may not > even exist (otherwise it wouldn't be a band-aid but be a real > feature) ;-) Indeed. My hope is that we can get rid of it once the scripted `git-add--interactive.perl` is removed in favor of the built-in add -i/-p. This is a long way off, of course. > > This fixes the case where one hunk inserts a line before the first line, > > and is followed by a hunk whose context overlaps with the first one's > > and which appends a line at the end. > > The in-code comment makes me wonder if we need to further loosen the > check in the other direction, though. What makes begin more special > than end? Can a hunk be seen that pretends to extend to the end but > no longer does because there was an overlapping hunk that has been > wiggled in? The beginning is more special than the end because it is associated with the line number 1. The end line number is flexible already. There is another difference: after splitting hunks, the first hunk is applied first, and may render the line numbers of succeeding hunks incorrect. The same is not true for the last hunk: it cannot render the preceding hunks' line numbers incorrect, as it has not been applied yet. I think that's why `--allow-overlap` works with this patch when adding lines both to the beginning and to the end after splitting a single hunk. Ciao, Dscho > > Signed-off-by: Johannes Schindelin <johannes.schindelin@xxxxxx> > > --- > > apply.c | 10 ++++++++++ > > 1 file changed, 10 insertions(+) > > > > diff --git a/apply.c b/apply.c > > index f8a046a6a5..720a631eaa 100644 > > --- a/apply.c > > +++ b/apply.c > > @@ -2661,6 +2661,16 @@ static int find_pos(struct apply_state *state, > > unsigned long backwards, forwards, current; > > int backwards_lno, forwards_lno, current_lno; > > > > + /* > > + * When running with --allow-overlap, it is possible that a hunk is > > + * seen that pretends to start at the beginning (but no longer does), > > + * and that *still* needs to match the end. So trust `match_end` more > > + * than `match_beginning`. > > + */ > > + if (state->allow_overlap && match_beginning && match_end && > > + img->nr - preimage->nr != 0) > > + match_beginning = 0; > > + > > /* > > * If match_beginning or match_end is specified, there is no > > * point starting from a wrong line that will never match and >
