panic: bad mutations size: 2 ([{/_sanity/key [118 97 108 117 101] [2 0 0 0 0 0 0 0]} {/_sanity/key [110 101 119 32 118 97 108 117 101] [3 0 0 0 0 0 0 0]}])

With Go 1.10 x86_64 and

• couchbase-clog dcae662
• couchbase a064ca4
• gomemcached db8741d
• couchbase-cbauth 7de3ac3
• couchbase-goutils a8bc32b
• davecgh-spew 8991bc2
• pallinder-randomdata- 0eb4fb8
• pkg-errors 0.8.0
• pmezard-difflib 1.0.0
• stretchr-objx 8a3f715
• stretchr-testify 1.2.1
• golang-x-crypt 88942b9
• golang-x-sys-unix- 91ee8cd

I'm getting:

+ GOPATH=/builddir/build/BUILD/cbauth-7de3ac3566b1be6200e58ed9b1e68653b0606ad8/_build:/usr/share/gocode
+ go test -buildmode pie -compiler gc -ldflags '-extldflags '\''-Wl,-z,relro  '\'''
2018/03/26 04:52:02 Waiting for rows
2018/03/26 04:52:02 Observed {/_sanity/key, value, ^B^@^@^@^@^@^@^@}
2018/03/26 04:52:02 Observed {/_sanity/key, new value, ^C^@^@^@^@^@^@^@}
2018/03/26 04:52:02 Observed {/_sanity/key, , %!s(<nil>)}
2018/03/26 04:52:02 receiver is dead
--- FAIL: TestSanity (0.00s)
        metakv_test.go:291: Starting basic sanity test
        metakv_test.go:291: cleaned up /_sanity/ subspace
        metakv_test.go:291: Sanity observe loop exited
panic: bad mutations size: 2 ([{/_sanity/key [118 97 108 117 101] [2 0 0 0 0 0 0 0]} {/_sanity/key [110 101 119 32 118 97 108 117 101] [3 0 0 0 0 0 0
 0]}]) [recovered]
        panic: bad mutations size: 2 ([{/_sanity/key [118 97 108 117 101] [2 0 0 0 0 0 0 0]} {/_sanity/key [110 101 119 32 118 97 108 117 101] [3 0 0
 0 0 0 0 0]}])

goroutine 5 [running]:
testing.tRunner.func1(0xc42021a000)
        /usr/lib/golang/src/testing/testing.go:742 +0x29f
panic(0x5557316a3620, 0xc420010600)
        /usr/lib/golang/src/runtime/panic.go:505 +0x22d
github.com/couchbase/cbauth/metakv.doExecuteBasicSanityTest(0xc42016c1e0, 0xc420010100)
        /builddir/build/BUILD/cbauth-7de3ac3566b1be6200e58ed9b1e68653b0606ad8/_build/src/github.com/couchbase/cbauth/metakv/sanity.go:115 +0x1521
github.com/couchbase/cbauth/metakv.TestSanity(0xc42021a000)
        /builddir/build/BUILD/cbauth-7de3ac3566b1be6200e58ed9b1e68653b0606ad8/_build/src/github.com/couchbase/cbauth/metakv/metakv_test.go:291 +0x236
testing.tRunner(0xc42021a000, 0x55573173f338)
        /usr/lib/golang/src/testing/testing.go:777 +0xd2
created by testing.(*T).Run
        /usr/lib/golang/src/testing/testing.go:824 +0x2e2
exit status 2
FAIL    github.com/couchbase/cbauth/metakv      0.021s

Start by running the metakv package tests, focusing on metakv/sanity.go around line 115 and metakv/metakv_test.go around line 291. Trace the observed mutations and the bad-mutations-size panic under Go 1.10. Done means TestSanity completes without the panic and the reported mutation sequence is handled correctly.