rev-list: use hdr_termination instead of a always using a newline

When adding support for prefixing output of log and other commands using
--line-prefix, commit 660e113ce118 ("graph: add support for
--line-prefix on all graph-aware output", 2016-08-31) accidentally
broke rev-list --header output.

In order to make the output appear with a line-prefix, the flow was
changed to always use the graph subsystem for display. Unfortunately
the graph flow in rev-list did not use info->hdr_termination as it was
assumed that graph output would never need to putput NULs.

Since we now always use the graph code in order to handle the case of
line-prefix, simply replace putchar('\n') with
putchar(info->hdr_termination) which will correct this issue.

Add a test for the --header case to make sure we don't break it in the
future.

Reported-by: Dennis Kaarsemaker <dennis@kaarsemaker.net>
Signed-off-by: Jacob Keller <jacob.keller@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Jacob Keller <jacob.keller@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

2 files changed, 15 insertions, 1 deletions

diff --git a/builtin/rev-list.c b/builtin/rev-list.c
index 8479f6ed28..c43decda70 100644
--- a/builtin/rev-list.c
+++ b/builtin/rev-list.c
@@ -145,7 +145,7 @@ static void show_commit(struct commit *commit, void *data)
                          */
                         if (buf.len && buf.buf[buf.len - 1] == '\n')
                                 graph_show_padding(revs->graph);
-                        putchar('\n');
+                        putchar(info->hdr_termination);
                 } else {
                         /*
                          * If the message buffer is empty, just show
diff --git a/t/t6000-rev-list-misc.sh b/t/t6000-rev-list-misc.sh
index 3e752ce032..969e4e9e52 100755
--- a/t/t6000-rev-list-misc.sh
+++ b/t/t6000-rev-list-misc.sh
@@ -100,4 +100,18 @@ test_expect_success '--bisect and --first-parent can not be combined' '
         test_must_fail git rev-list --bisect --first-parent HEAD
 '
 
+test_expect_success '--header shows a NUL after each commit' '
+        # We know that there is no Q in the true payload; names and
+        # addresses of the authors and the committers do not have
+        # any, and object names or header names do not, either.
+        git rev-list --header --max-count=2 HEAD |
+        nul_to_q |
+        grep "^Q" >actual &&
+        cat >expect <<-EOF &&
+        Q$(git rev-parse HEAD~1)
+        Q
+        EOF
+        test_cmp expect actual
+'
+
 test_done