[PATCH v2 5/8] xdiff: -W: don't include common trailing empty lines in context

["René Scharfe" <l.s.r@web.de>]

Empty lines between functions are shown by diff -W, as it considers them
to be part of the function preceding them.  They are not interesting in
most languages.  The previous patch stopped showing them in the special
case of a function added at the end of a file.

Stop extending context to those empty lines by skipping back over them
from the start of the next function.

Signed-off-by: Rene Scharfe <l.s.r@web.de>
---
 t/t4051-diff-function-context.sh | 4 ++--
 xdiff/xemit.c                    | 2 ++
 2 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/t/t4051-diff-function-context.sh b/t/t4051-diff-function-context.sh
index b191c655..9fe590f 100755
--- a/t/t4051-diff-function-context.sh
+++ b/t/t4051-diff-function-context.sh
@@ -85,7 +85,7 @@ test_expect_success ' context does not include preceding empty lines' '
 	test "$(first_context_line <changed_hello.diff)" != " "
 '
 
-test_expect_failure ' context does not include trailing empty lines' '
+test_expect_success ' context does not include trailing empty lines' '
 	test "$(last_context_line <changed_hello.diff)" != " "
 '
 
@@ -103,7 +103,7 @@ test_expect_success ' context does not include other functions' '
 	test $(grep -c "^[ +-].*Begin" changed_includes.diff) -le 1
 '
 
-test_expect_failure ' context does not include trailing empty lines' '
+test_expect_success ' context does not include trailing empty lines' '
 	test "$(last_context_line <changed_includes.diff)" != " "
 '
 
diff --git a/xdiff/xemit.c b/xdiff/xemit.c
index 29cec12..bfa53d3 100644
--- a/xdiff/xemit.c
+++ b/xdiff/xemit.c
@@ -231,6 +231,8 @@ int xdl_emit_diff(xdfenv_t *xe, xdchange_t *xscr, xdemitcb_t *ecb,
 			long fe1 = get_func_line(xe, xecfg, NULL,
 						 xche->i1 + xche->chg1,
 						 xe->xdf1.nrec);
+			while (fe1 > 0 && is_empty_rec(&xe->xdf1, fe1 - 1))
+				fe1--;
 			if (fe1 < 0)
 				fe1 = xe->xdf1.nrec;
 			if (fe1 > e1) {
-- 
2.8.3