Re: [PATCH 2/3] xdiff: -W: include immediately preceding non-empty lines in context
Am 15.01.2017 um 03:39 schrieb Junio C Hamano:
Show 27 quoted lines
> René Scharfe <l.s.r@web.de> writes:
>
>>> I am also more focused on keeping the codebase maintainable in good
>>> health by making sure that we made an effort to find a solution that
>>> is general-enough before solving a single specific problem you have
>>> today. We may end up deciding that a blank-line heuristics gives us
>>> good enough tradeoff, but I do not want us to make a decision before
>>> thinking.
>>
>> How about extending the context upward only up to and excluding a line
>> that is either empty *or* a function line? That would limit the extra
>> context to a single function in the worst case.
>>
>> Reducing context at the bottom with the aim to remove comments for the
>> next section is more tricky as it could remove part of the function
>> that we'd like to show if we get the boundary wrong. How bad would it
>> be to keep the southern border unchanged?
>
> I personally do not think there is any robust heuristic other than
> Vegard's "a blank line may be a signal enough that lines before that
> are not part of the beginning of the function", and I think your
> "hence we look for a blank line but if there is a line that matches
> the function header, stop there as we know we came too far back"
> will be a good-enough safety measure.
>
> I also agree with you that we probably do not want to futz with the
> southern border.
A replacement patch for 2/3 with these changes would look like this:
diff --git a/xdiff/xemit.c b/xdiff/xemit.c
index 8c88dbde38..9ed54cd318 100644
--- a/xdiff/xemit.c
+++ b/xdiff/xemit.c
@@ -174,11 +174,11 @@ int xdl_emit_diff(xdfenv_t *xe, xdchange_t *xscr, xdemitcb_t *ecb,
s2 = XDL_MAX(xch->i2 - xecfg->ctxlen, 0);
if (xecfg->flags & XDL_EMIT_FUNCCONTEXT) {
+ char dummy[1];
long fs1, i1 = xch->i1;
/* Appended chunk? */
if (i1 >= xe->xdf1.nrec) {
- char dummy[1];
long i2 = xch->i2;
/*
@@ -200,6 +200,10 @@ int xdl_emit_diff(xdfenv_t *xe, xdchange_t *xscr, xdemitcb_t *ecb,
}
fs1 = get_func_line(xe, xecfg, NULL, i1, -1);
+ while (fs1 > 0 && !is_empty_rec(&xe->xdf1, fs1 - 1) &&
+ match_func_rec(&xe->xdf1, xecfg, fs1 - 1,
+ dummy, sizeof(dummy)) < 0)
+ fs1--;
if (fs1 < 0)
fs1 = 0;
if (fs1 < s1) {
René Scharfe <l.s.r@web.de>