[PATCH v3 01/12] sequencer: avoid using errno clobbered by rollback_lock_file()

[Johannes Schindelin <johannes.schindelin@xxxxxx>]

As pointed out in a review of the `--recreate-merges` patch series,
`rollback_lock_file()` clobbers errno. Therefore, we have to report the
error message that uses errno before calling said function.

Signed-off-by: Johannes Schindelin <johannes.schindelin@xxxxxx>
---
 sequencer.c | 13 ++++++++-----
 1 file changed, 8 insertions(+), 5 deletions(-)

diff --git a/sequencer.c b/sequencer.c
index 4d3f60594cb..114db3b2775 100644
--- a/sequencer.c
+++ b/sequencer.c
@@ -296,12 +296,14 @@ static int write_message(const void *buf, size_t len, const char *filename,
 	if (msg_fd < 0)
 		return error_errno(_("could not lock '%s'"), filename);
 	if (write_in_full(msg_fd, buf, len) < 0) {
+		error_errno(_("could not write to '%s'"), filename);
 		rollback_lock_file(&msg_file);
-		return error_errno(_("could not write to '%s'"), filename);
+		return -1;
 	}
 	if (append_eol && write(msg_fd, "\n", 1) < 0) {
+		error_errno(_("could not write eol to '%s'"), filename);
 		rollback_lock_file(&msg_file);
-		return error_errno(_("could not write eol to '%s'"), filename);
+		return -1;
 	}
 	if (commit_lock_file(&msg_file) < 0) {
 		rollback_lock_file(&msg_file);
@@ -1584,16 +1586,17 @@ static int save_head(const char *head)
 
 	fd = hold_lock_file_for_update(&head_lock, git_path_head_file(), 0);
 	if (fd < 0) {
+		error_errno(_("could not lock HEAD"));
 		rollback_lock_file(&head_lock);
-		return error_errno(_("could not lock HEAD"));
+		return -1;
 	}
 	strbuf_addf(&buf, "%s\n", head);
 	written = write_in_full(fd, buf.buf, buf.len);
 	strbuf_release(&buf);
 	if (written < 0) {
+		error_errno(_("could not write to '%s'"), git_path_head_file());
 		rollback_lock_file(&head_lock);
-		return error_errno(_("could not write to '%s'"),
-				   git_path_head_file());
+		return -1;
 	}
 	if (commit_lock_file(&head_lock) < 0) {
 		rollback_lock_file(&head_lock);
-- 
2.16.1.windows.1