Merge branch 'rs/xdiff-hunk-with-func-line' into maint

"git show -W" (extend hunks to cover the entire function, delimited
by lines that match the "funcname" pattern) used to show the entire
file when a change added an entire function at the end of the file,
which has been fixed.

* rs/xdiff-hunk-with-func-line:
  xdiff: fix merging of appended hunk with -W
  grep: -W: don't extend context to trailing empty lines
  t7810: add test for grep -W and trailing empty context lines
  xdiff: don't trim common tail with -W
  xdiff: -W: don't include common trailing empty lines in context
  xdiff: ignore empty lines before added functions with -W
  xdiff: handle appended chunks better with -W
  xdiff: factor out match_func_rec()
  t4051: rewrite, add more tests

1 files changed, 4 insertions, 6 deletions

diff --git a/xdiff-interface.c b/xdiff-interface.c
index 54236f24b9..f34ea762e4 100644
--- a/xdiff-interface.c
+++ b/xdiff-interface.c
@@ -100,9 +100,9 @@ static int xdiff_outf(void *priv_, mmbuffer_t *mb, int nbuf)
 
 /*
  * Trim down common substring at the end of the buffers,
- * but leave at least ctx lines at the end.
+ * but end on a complete line.
  */
-static void trim_common_tail(mmfile_t *a, mmfile_t *b, long ctx)
+static void trim_common_tail(mmfile_t *a, mmfile_t *b)
 {
 	const int blk = 1024;
 	long trimmed = 0, recovered = 0;
@@ -110,9 +110,6 @@ static void trim_common_tail(mmfile_t *a, mmfile_t *b, long ctx)
 	char *bp = b->ptr + b->size;
 	long smaller = (a->size < b->size) ? a->size : b->size;
 
-	if (ctx)
-		return;
-
 	while (blk + trimmed <= smaller && !memcmp(ap - blk, bp - blk, blk)) {
 		trimmed += blk;
 		ap -= blk;
@@ -134,7 +131,8 @@ int xdi_diff(mmfile_t *mf1, mmfile_t *mf2, xpparam_t const *xpp, xdemitconf_t co
 	if (mf1->size > MAX_XDIFF_SIZE || mf2->size > MAX_XDIFF_SIZE)
 		return -1;
 
-	trim_common_tail(&a, &b, xecfg->ctxlen);
+	if (!xecfg->ctxlen && !(xecfg->flags & XDL_EMIT_FUNCCONTEXT))
+		trim_common_tail(&a, &b);
 
 	return xdl_diff(&a, &b, xpp, xecfg, xecb);
 }