From: Tom Clegg <tom@curii.com>
Date: Tue, 30 Nov 2021 21:01:19 +0000 (-0500)
Subject: Fix deadlock in skip-on-error case.
X-Git-Url: https://git.arvados.org/lightning.git/commitdiff_plain/6b9d7d362961d257277641bfb57f3fa89e1345dc

Fix deadlock in skip-on-error case.

No issue #

Arvados-DCO-1.1-Signed-off-by: Tom Clegg <tom@curii.com>
---

diff --git a/throttle.go b/throttle.go
index ce3279dd33..8b087eeae2 100644
--- a/throttle.go
+++ b/throttle.go
@@ -19,7 +19,12 @@ type throttle struct {
 }
 
 func (t *throttle) Acquire() {
-	t.setupOnce.Do(func() { t.ch = make(chan bool, t.Max) })
+	t.setupOnce.Do(func() {
+		if t.Max < 1 {
+			panic("throttle.Max < 1")
+		}
+		t.ch = make(chan bool, t.Max)
+	})
 	t.wg.Add(1)
 	t.ch <- true
 }
@@ -48,6 +53,7 @@ func (t *throttle) Wait() error {
 func (t *throttle) Go(f func() error) error {
 	t.Acquire()
 	if t.Err() != nil {
+		t.Release()
 		return t.Err()
 	}
 	go func() {