Wait for child on signal death for aliases to builtins

When you hit ^C all the processes in the tree receives it. When a git
command uses a pager, git ignores this and waits until the pager quits.
However, when using an alias there is an additional process in the tree
which didn't ignore the signal. That caused it to exit which in turn
caused the pager to exit. This fixes that for aliases to builtins.

This was originally fixed in 46df690 (execv_dashed_external: wait
for child on signal death, 2017-01-06), but was broken by ee4512e
(trace2: create new combined trace facility, 2019-02-22) and then
b914084 (git: avoid calling aliased builtins via their dashed form,
2019-07-29).

Signed-off-by: Trygve Aaberge <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: trygveaa

git.c

@@ -768,7 +768,7 @@ static int run_argv(int *argcp, const char ***argv)
 			 * OK to return. Otherwise, we just pass along the status code.
 			 */
 			i = run_command_v_opt_tr2(args.argv, RUN_SILENT_EXEC_FAILURE |
-						  RUN_CLEAN_ON_EXIT, "git_alias");
+						  RUN_CLEAN_ON_EXIT | RUN_WAIT_AFTER_CLEAN, "git_alias");
 			if (i >= 0 || errno != ENOENT)
 				exit(i);
 			die("could not execute builtin %s", **argv);

run-command.c

@@ -1039,6 +1039,7 @@ int run_command_v_opt_cd_env_tr2(const char **argv, int opt, const char *dir,
 	cmd.silent_exec_failure = opt & RUN_SILENT_EXEC_FAILURE ? 1 : 0;
 	cmd.use_shell = opt & RUN_USING_SHELL ? 1 : 0;
 	cmd.clean_on_exit = opt & RUN_CLEAN_ON_EXIT ? 1 : 0;
+	cmd.wait_after_clean = opt & RUN_WAIT_AFTER_CLEAN ? 1 : 0;
 	cmd.dir = dir;
 	cmd.env = env;
 	cmd.trace2_child_class = tr2_class;

run-command.h

@@ -224,6 +224,7 @@ int run_hook_ve(const char *const *env, const char *name, va_list args);
 #define RUN_SILENT_EXEC_FAILURE 8
 #define RUN_USING_SHELL 16
 #define RUN_CLEAN_ON_EXIT 32
+#define RUN_WAIT_AFTER_CLEAN 64
 
 /**
  * Convenience functions that encapsulate a sequence of