[PATCH v3 33/38] sequencer (rebase -i): show only failed `git commit`'s output

[Johannes Schindelin]

This is the behavior of the shell script version of the interactive
rebase, by using the `output` function defined in `git-rebase.sh`.

Signed-off-by: Johannes Schindelin <johannes.schinde...@gmx.de>
---
 sequencer.c | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/sequencer.c b/sequencer.c
index c7dc5a2ad4..a501dfce38 100644
--- a/sequencer.c
+++ b/sequencer.c
@@ -610,6 +610,11 @@ static int run_git_commit(const char *defmsg, struct 
replay_opts *opts,
        cmd.git_cmd = 1;
 
        if (is_rebase_i(opts)) {
+               if (!edit) {
+                       cmd.stdout_to_stderr = 1;
+                       cmd.err = -1;
+               }
+
                if (read_env_script(&cmd.env_array)) {
                        const char *gpg_opt = gpg_sign_opt_quoted(opts);
 
@@ -644,6 +649,19 @@ static int run_git_commit(const char *defmsg, struct 
replay_opts *opts,
        if (opts->allow_empty_message)
                argv_array_push(&cmd.args, "--allow-empty-message");
 
+       if (cmd.err == -1) {
+               /* hide stderr on success */
+               struct strbuf buf = STRBUF_INIT;
+               int rc = pipe_command(&cmd,
+                                     NULL, 0,
+                                     /* stdout is already redirected */
+                                     NULL, 0,
+                                     &buf, 0);
+               if (rc)
+                       fputs(buf.buf, stderr);
+               strbuf_release(&buf);
+               return rc;
+       }
 
        return run_command(&cmd);
 }
-- 
2.11.0.rc3.windows.1