run-command API: have "run_processes_parallel{,_tr2}()" return void

Change the "run_processes_parallel{,_tr2}()" functions to return void,
instead of int. Ever since c553c72eed6 (run-command: add an
asynchronous parallel child processor, 2015-12-15) they have
unconditionally returned 0.

To get a "real" return value out of this function the caller needs to
get it via the "task_finished_fn" callback, see the example in hook.c
added in 96e7225b310 (hook: add 'run' subcommand, 2021-12-22).

So the "result = " and "if (!result)" code added to "builtin/fetch.c"
d54dea77dba (fetch: let --jobs=<n> parallelize --multiple, too,
2019-10-05) has always been redundant, we always took that "if"
path. Likewise the "ret =" in "t/helper/test-run-command.c" added in
be5d88e1128 (test-tool run-command: learn to run (parts of) the
testsuite, 2019-10-04) wasn't used, instead we got the return value
from the "if (suite.failed.nr > 0)" block seen in the context.

Subsequent commits will alter this API interface, getting rid of this
always-zero return value makes it easier to understand those changes.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 11 insertions, 16 deletions

diff --git a/run-command.c b/run-command.c
index 5ec3a46dcc..642e6b6e05 100644
--- a/run-command.c
+++ b/run-command.c
@@ -1783,11 +1783,11 @@ static int pp_collect_finished(struct parallel_processes *pp)
 	return result;
 }
 
-int run_processes_parallel(int n,
-			   get_next_task_fn get_next_task,
-			   start_failure_fn start_failure,
-			   task_finished_fn task_finished,
-			   void *pp_cb)
+void run_processes_parallel(int n,
+			    get_next_task_fn get_next_task,
+			    start_failure_fn start_failure,
+			    task_finished_fn task_finished,
+			    void *pp_cb)
 {
 	int i, code;
 	int output_timeout = 100;
@@ -1834,25 +1834,20 @@ int run_processes_parallel(int n,
 	}
 
 	pp_cleanup(&pp);
-	return 0;
 }
 
-int run_processes_parallel_tr2(int n, get_next_task_fn get_next_task,
-			       start_failure_fn start_failure,
-			       task_finished_fn task_finished, void *pp_cb,
-			       const char *tr2_category, const char *tr2_label)
+void run_processes_parallel_tr2(int n, get_next_task_fn get_next_task,
+				start_failure_fn start_failure,
+				task_finished_fn task_finished, void *pp_cb,
+				const char *tr2_category, const char *tr2_label)
 {
-	int result;
-
 	trace2_region_enter_printf(tr2_category, tr2_label, NULL, "max:%d",
 				   ((n < 1) ? online_cpus() : n));
 
-	result = run_processes_parallel(n, get_next_task, start_failure,
-					task_finished, pp_cb);
+	run_processes_parallel(n, get_next_task, start_failure,
+			       task_finished, pp_cb);
 
 	trace2_region_leave(tr2_category, tr2_label, NULL);
-
-	return result;
 }
 
 int run_auto_maintenance(int quiet)