Ævar Arnfjörð Bjarmason <avarab@xxxxxxxxx> writes:
> - We use this warning as a proxy for "let's not run for a day",
> otherwise we'll just grind on gc --auto trying to consolidate
> possibly many hundreds of K of loose objects only to find none of
> them can be pruned because the run into the expiry policy. With the
> warning we retry that once per day, which sucks less.
>
> - This conflation of the user-visible warning and the policy is an
> emergent effect of how the different gc pieces interact, which as I
> note in the linked thread(s) sucks.
>
> But we can't just yank one piece away (as Jonathan's patch does)
> without throwing the baby out with the bathwater.
>
> It will mean that e.g. if you have 10k loose objects in your git.git,
> and created them just now, that every time you run anything that runs
> "gc --auto" we'll fork to the background, peg a core at 100% CPU for
> 2-3 minutes or whatever it is, only do get nowhere and do the same
> thing again in ~3 minutes when you run your next command.
We probably can keep the "let's not run for a day" safety while
pretending that "git gc -auto" succeeded for callers like "git svn"
so that these callers do not hae to do "eval { ... }" to hide our
exit code, no?
I think that is what Jonathan's patch (jn/gc-auto) does.
From: Jonathan Nieder <jrnieder@xxxxxxxxx>
Date: Mon, 16 Jul 2018 23:57:40 -0700
Subject: [PATCH] gc: do not return error for prior errors in daemonized mode
diff --git a/builtin/gc.c b/builtin/gc.c
index 95c8afd07b..ce8a663a01 100644
--- a/builtin/gc.c
+++ b/builtin/gc.c
@@ -438,9 +438,15 @@ static const char *lock_repo_for_gc(int force, pid_t* ret_pid)
return NULL;
}
-static void report_last_gc_error(void)
+/*
+ * Returns 0 if there was no previous error and gc can proceed, 1 if
+ * gc should not proceed due to an error in the last run. Prints a
+ * message and returns -1 if an error occured while reading gc.log
+ */
+static int report_last_gc_error(void)
{
struct strbuf sb = STRBUF_INIT;
+ int ret = 0;
...
if (len < 0)
+ ret = error_errno(_("cannot read '%s'"), gc_log_path);
+ else if (len > 0) {
+ /*
+ * A previous gc failed. Report the error, and don't
+ * bother with an automatic gc run since it is likely
+ * to fail in the same way.
+ */
+ warning(_("The last gc run reported the following. "
"Please correct the root cause\n"
"and remove %s.\n"
"Automatic cleanup will not be performed "
"until the file is removed.\n\n"
"%s"),
gc_log_path, sb.buf);
+ ret = 1;
+ }
strbuf_release(&sb);
done:
free(gc_log_path);
+ return ret;
}
I.e. report_last_gc_error() returns 1 when finds that the previous
attempt to "gc --auto" failed. And then
@@ -561,7 +576,13 @@ int cmd_gc(int argc, const char **argv, const char *prefix)
fprintf(stderr, _("See \"git help gc\" for manual housekeeping.\n"));
}
if (detach_auto) {
- report_last_gc_error(); /* dies on error */
+ int ret = report_last_gc_error();
+ if (ret < 0)
+ /* an I/O error occured, already reported */
+ exit(128);
+ if (ret == 1)
+ /* Last gc --auto failed. Skip this one. */
+ return 0;
... it exits with 0 without bothering to rerun "gc".
So it won't get stuck for 3 minutes; the repository after "gc
--auto" punts will stay to be suboptimal for a day, and the user
kill not get an "actionable" error notice (due to this hiding of
previous error), hence cannot make changes that may help like
shortening expiry period, though.
