Flaky test on CI pipeline

[liunyl]

What happened?

http://35.222.141.150:8080/teams/main/pipelines/eloqkv_main_ent/jobs/compile-test/builds/73
Tcl test failed at mono/list.tcl

*** [err]: BRPOP: with single empty list argument in tests//unit/mono/list.tcl
Expected 'blist1 foo' to be equal to '' (context: type eval line 7 cmd {assert_equal {blist1 foo} [$rd read]} proc ::test)

Steps to Reproduce

Environment

• OS:
• Version:
• Any other relevant details:

[yi-xmu]

Try to reproduce.

[yi-xmu]

Another CI failed info:

http://35.222.141.150:8080/teams/main/pipelines/eloqkv_main_ent/jobs/compile-test/builds/78

is_cluster=false


[err]: BLMPOP_RIGHT: arguments are empty in tests//unit/mono/list.tcl
Expected 'blist1{t} foo' to be equal to '' (context: type eval line 8 cmd {assert_equal {blist1{t} foo} [$rd read]} proc ::test)

[yi-xmu]

For the test case:

foreach {pop} {BLPOP BRPOP BLMPOP_LEFT BLMPOP_RIGHT} 
...
        test "$pop: with single empty list argument" {
            set rd [redis_deferring_client]
            r del blist1
            bpop_command $rd $pop blist1 1
            wait_for_blocked_client
            r rpush blist1 foo
            assert_equal {blist1 foo} [$rd read]
            assert_equal 0 [r exists blist1]
            $rd close
        }

It is speculated that the rpush command has not been completed before the bpop command times out, causing bpop to return a null value.

Then, add debug log and try to reproduce it.

But, after several times, can not reproduce this bug.

[yi-xmu]

Can not reproduce neither in local machine nor CI pipeline.

[MrGuin]

This happens frequently recently. Added some debug log in #148.