lib/PublicInbox/V2Writable.pm | 9 ++-------
 t/xcpdb-reshard.t             | 2 +-

diff --git a/lib/PublicInbox/V2Writable.pm b/lib/PublicInbox/V2Writable.pm
index 8ad71b54ee6fe7088a64e95637309ce914e9c790..37d27302565e17b66586b00e5742a6b2ef451f41 100644
--- a/lib/PublicInbox/V2Writable.pm
+++ b/lib/PublicInbox/V2Writable.pm
@@ -34,13 +34,8 @@ our $NPROC_MAX_DEFAULT = 4;
 
 sub nproc_shards ($) {
 	my ($creat_opt) = @_;
-	if (ref($creat_opt) eq 'HASH') {
-		if (defined(my $n = $creat_opt->{nproc})) {
-			return $n
-		}
-	}
-
-	my $n = $ENV{NPROC};
+	my $n = $creat_opt->{nproc} if ref($creat_opt) eq 'HASH';
+	$n //= $ENV{NPROC};
 	if (!$n) {
 		chomp($n = `nproc 2>/dev/null`);
 		# assume 2 cores if GNU nproc(1) is not available
diff --git a/t/xcpdb-reshard.t b/t/xcpdb-reshard.t
index 9f0034f1581305b5c32ab29f463876385087790a..5fce5ead7612b1b81aa5a80bfd93db9cfdc03ee7 100644
--- a/t/xcpdb-reshard.t
+++ b/t/xcpdb-reshard.t
@@ -40,7 +40,7 @@ 	ok($im->add($mime), "message $i added");
 }
 $im->done;
 my @shards = grep(m!/\d+\z!, glob("$ibx->{inboxdir}/xap*/*"));
-is(scalar(@shards), $nproc, 'got expected shards');
+is(scalar(@shards), $nproc - 1, 'got expected shards');
 my $orig = $ibx->over->query_xover(1, $ndoc);
 my %nums = map {; "$_->{num}" => 1 } @$orig;