CI random failure: ChannelQueue, panic, invalid memory address or nil pointer dereference

[wxiaoguang]

https://drone.gitea.io/go-gitea/gitea/56024/2/12

2022/06/13 02:49:01 ...ueue_channel_test.go:170:func3() [I] Finally terminating
2022/06/13 02:49:01 ...eue/queue_channel.go:154:func1() [W] ChannelQueue:  Terminated before completed flushing
2022/06/13 02:49:01 ...eue/queue_channel.go:154:func1() [W] ChannelQueue: second-channel Terminated before completed flushing

panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x1 addr=0x0 pc=0xc89081]
goroutine 30 [running]:
github.com/syndtr/goleveldb/leveldb.(*DB).isClosed(...)
	/go/pkg/mod/github.com/syndtr/goleveldb@v1.0.0/leveldb/db_state.go:230
github.com/syndtr/goleveldb/leveldb.(*DB).ok(...)
	/go/pkg/mod/github.com/syndtr/goleveldb@v1.0.0/leveldb/db_state.go:235
github.com/syndtr/goleveldb/leveldb.(*DB).Get(0x0, {0xc0000f7a98, 0x8, 0x8}, 0xc00025a1e8?)
	/go/pkg/mod/github.com/syndtr/goleveldb@v1.0.0/leveldb/db.go:838 +0x81
gitea.com/lunny/levelqueue.(*Queue).RPop(0xc00012e100)
	/go/pkg/mod/gitea.com/lunny/levelqueue@v0.4.1/queue.go:198 +0x327
code.gitea.io/gitea/modules/queue.(*LevelQueueByteFIFO).Pop(0xc0003922e8, {0x0?, 0x3?})
	/drone/src/modules/queue/queue_disk.go:104 +0x52
code.gitea.io/gitea/modules/queue.(*ByteFIFOQueue).doPop(0xc000242320)
	/drone/src/modules/queue/queue_bytefifo.go:299 +0x128
code.gitea.io/gitea/modules/queue.(*ByteFIFOQueue).readToChan(0xc000242320)
	/drone/src/modules/queue/queue_bytefifo.go:234 +0x7e5
code.gitea.io/gitea/modules/queue.(*ByteFIFOQueue).Run(0xc000242320, 0x10c4880, 0x10c4888)
	/drone/src/modules/queue/queue_bytefifo.go:164 +0x413
created by code.gitea.io/gitea/modules/queue.(*PersistableChannelQueue).Run
	/drone/src/modules/queue/queue_disk_channel.go:178 +0x67d
FAIL	code.gitea.io/gitea/modules/queue	0.227s