On Fri, 19 Mar 2010 06:45:12 +0200 Jari Aalto <jari.aa...@cante.net> wrote:
> Would you have any insight on this bug: > > http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=271766 > > Unfortunately there is no test cases to try, so it's a long shot. Fortunately there is enough of a test-case. I found a suitable xfaces.c at http://www.opensource.apple.com/source/emacs/emacs-60/emacs/src/xfaces.c?txt I have fixed the problem and the fix can be found at http://neil.brown.name/git?p=wiggle;a=commitdiff;h=8420e684cf3736de120db8f7828408d06240566c Running "wiggle -d" on just the .rej file is quite telling. The diff that is generated has no end context. This confuses wiggle's merge routine. It probably shouldn't but it does. I fixed the diff fixup code to restore the end context. The important part of the patch is below. Thanks for the report. (pity it has taken over 5 years to find out about this bug and fix it ... I really should spend more time on wiggle!) NeilBrown diff --git a/diff.c b/diff.c index 49f87d1..9e3e7cc 100644 --- a/diff.c +++ b/diff.c @@ -243,45 +243,58 @@ static struct csl *lcsl(struct file *a, int alo, int ahi, return csl; } -/* if two common sequences are separated by only an add or remove, +/* If two common sequences are separated by only an add or remove, * and the first common ends the same as the middle text, * extend the second and contract the first in the hope that the * first might become empty. This ameliorates against the greedyness * of the 'diff' algorithm. + * We treat the final zero-length 'csl' as a common sequence which + * can be extended so we much make sure to add a new zero-length csl + * to the end. * Once this is done, repeat the process but extend the first - * in favour of the second. The acknowledges that semantic units - * more often end with common text ("return 0;\n}\n", "\n") than - * start with it. + * in favour of the second but only up to the last newline. This + * acknowledges that semantic units more often end with common + * text ("return 0;\n}\n", "\n") than start with it. */ static void fixup(struct file *a, struct file *b, struct csl *list) { struct csl *list1, *orig; int lasteol = -1; + int found_end = 0; if (!list) return; orig = list; list1 = list+1; - while (list->len && list1->len) { + while (list->len) { + if (list1->len == 0) + found_end = 1; + if ((list->a+list->len == list1->a && + list->b+list->len != list1->b && /* text at b inserted */ match(&b->list[list->b+list->len-1], &b->list[list1->b-1]) - ) + ) || (list->b+list->len == list1->b && + list->a+list->len != list1->a && /* text at a deleted */ match(&a->list[list->a+list->len-1], &a->list[list1->a-1]) ) ) { -/* printword(a->list[list1->a-1]); +#if 0 + printword(stderr, a->list[list1->a-1]); printf("fixup %d,%d %d : %d,%d %d\n", list->a,list->b,list->len, list1->a,list1->b,list1->len); -*/ if (ends_line(a->list[list->a+list->len-1]) +#endif + if (ends_line(a->list[list->a+list->len-1]) && a->list[list->a+list->len-1].len==1 && lasteol == -1 ) { -/* printf("E\n");*/ +#if 0 + printf("E\n"); +#endif lasteol = list1->a-1; } list1->a--; @@ -290,7 +303,12 @@ static void fixup(struct file *a, struct file *b, struct csl *list) list->len--; if (list->len == 0) { lasteol = -1; - if (list > orig) + if (found_end) { + *list = *list1; + list1->a += list1->len; + list1->b += list1->len; + list1->len = 0; + } else if (list > orig) list--; else { *list = *list1++; @@ -300,7 +318,8 @@ static void fixup(struct file *a, struct file *b, struct csl *list) } else { if (lasteol >= 0) { /* printf("seek %d\n", lasteol);*/ - while (list1->a <= lasteol && list1->len>1) { + while (list1->a <= lasteol && (list1->len>1 || + (found_end && list1->len > 0))) { list1->a++; list1->b++; list1->len--; @@ -308,10 +327,17 @@ static void fixup(struct file *a, struct file *b, struct csl *list) } lasteol=-1; } - *++list = *list1++; + *++list = *list1; + if (found_end) { + list1->a += list1->len; + list1->b += list1->len; + list1->len = 0; + } else + list1++; } + if (list->len && list1 == list) abort(); } - list[1] = list1[0]; + // list[1] = list1[0]; } struct csl *diff(struct file a, struct file b) -- To UNSUBSCRIBE, email to debian-bugs-dist-requ...@lists.debian.org with a subject of "unsubscribe". Trouble? Contact listmas...@lists.debian.org
