[PATCH 2/2] combine-diff: abort if --output is given

["René Scharfe" <l.s.r@web.de>]

The code for combined diffs currently only writes to stdout.  Abort and
report that fact instead of silently ignoring the --output option.  The
(empty) output file has already been created at that point, though.

Reported-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: René Scharfe <l.s.r@web.de>
---
 combine-diff.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/combine-diff.c b/combine-diff.c
index 11df1d7f39..b0ece95480 100644
--- a/combine-diff.c
+++ b/combine-diff.c
@@ -1501,6 +1501,9 @@ void diff_tree_combined(const struct object_id *oid,
 	if (opt->ignore_regex_nr)
 		die("combined diff and '%s' cannot be used together",
 		    "--ignore-matching-lines");
+	if (opt->close_file)
+		die("combined diff and '%s' cannot be used together",
+		    "--output");

 	/* nothing to do, if no parents */
 	if (!num_parent)
--
2.36.1