Handle atexit list internaly for unthreaded builds

Wrap atexit()s calls on unthreaded builds to handle callback list
internally.

This is needed because on unthreaded builds, asyncs inherits parent's
atexit() list, that gets run as soon as the async exit()s (and again at
the end of async's parent process). That led to remove temporary files
too early.

Also remove a by-atexit-callback guard against this kind of issue in
clone.c, as this patch makes it redundant.

Fixes test 5537 (temporary shallow file vanished before unpack-objects
could open it)

BTW remove an unused variable in shallow.c.

Helped-by: Duy Nguyen <pclouds@gmail.com>
Helped-by: Andreas Schwab <schwab@linux-m68k.org>
Helped-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Etienne Buira <etienne.buira@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 2 insertions, 5 deletions

diff --git a/shallow.c b/shallow.c
index 57f4afa6b..0cc3d4763 100644
--- a/shallow.c
+++ b/shallow.c
@@ -226,7 +226,6 @@ static void remove_temporary_shallow_on_signal(int signo)
 
 const char *setup_temporary_shallow(const struct sha1_array *extra)
 {
-	static int installed_handler;
 	struct strbuf sb = STRBUF_INIT;
 	int fd;
 
@@ -237,10 +236,8 @@ const char *setup_temporary_shallow(const struct sha1_array *extra)
 		strbuf_addstr(&temporary_shallow, git_path("shallow_XXXXXX"));
 		fd = xmkstemp(temporary_shallow.buf);
 
-		if (!installed_handler) {
-			atexit(remove_temporary_shallow);
-			sigchain_push_common(remove_temporary_shallow_on_signal);
-		}
+		atexit(remove_temporary_shallow);
+		sigchain_push_common(remove_temporary_shallow_on_signal);
 
 		if (write_in_full(fd, sb.buf, sb.len) != sb.len)
 			die_errno("failed to write to %s",