> Le 30 mai 2025 à 10:05, Patrick Steinhardt <ps@xxxxxx> a écrit : > > On Fri, May 30, 2025 at 08:55:49AM -0400, Ben Knoble wrote: >>> @@ -1240,6 +1251,7 @@ static int maintenance_task_gc(struct maintenance_run_opts *opts, >>> else >>> strvec_push(&child.args, "--no-quiet"); >>> strvec_push(&child.args, "--no-detach"); >>> + strvec_push(&child.args, "--skip-maintenance-before-detach"); >> >> I suspect this would be more obvious to me if I had the manual >> available right now, but if we are not detaching (« --no-detach ») why >> do we need to skip something before detaching (that presumably won’t >> happen)? > > We have two levels here: git-maintenance(1) and git-gc(1), where the > former executes the latter when the "gc" task is configured. What is > important to realize is that in this setup it is not git-gc(1) which > detaches -- it is git-maintenance(1). So git-maintenance(1) runs in the > background, but any tasks it invokes itself must run synchronously in > the foreground. > > The flow thus looks like this: > > 1. git-maintenance(1) starts. > 2. We perform the pre-detach tasks from git-gc(1) in the same process. > 3. We detach and thus the main process exits. > 4. We execute git-gc(1) in the already-detached process. > 5. We wait for git-gc(1) to exit. > 6. The detached git-maintenance(1) exits. > > So because (4) is running in the already-detached process we ask > git-gc(1) to not detach again. And because we already ran the pre-detach > tasks we also ask it to not run those again. > > Patrick Aha, thanks! I thought I understood the sequence, but I was wrong about some details. I was wondering if not detaching should just imply skipping work before a (non-existent) detach—if there’s no detach, should we do any pre-detach work at all? But presumably that does the wrong thing for (non-detaching) invocations that come from outside git-maintenance, doesn’t it? Hm. Maybe the flip-around for me is that « pre-detach work » here actually refers to « foreground work », which we obviously want to do even if we aren’t detaching, and which maintenance (which has already done this) needs to skip.
