testing: Don't silently ignore nested t.Cleanup calls

[prashantv]

What version of Go are you using (go version)?

$ go version
go version go1.15 linux/amd64

Does this issue reproduce with the latest release?

Yes

What operating system and processor architecture are you using (go env)?

go env Output

$ go env
GO111MODULE="on"
GOARCH="amd64"
GOBIN=""
GOCACHE="/home/user/.cache/go-build"
GOENV="/home/user/.config/go/env"
GOEXE=""
GOFLAGS=""
GOHOSTARCH="amd64"
GOHOSTOS="linux"
GOINSECURE=""
GOMODCACHE="/opt/go/path/pkg/mod"
GONOPROXY=""
GONOSUMDB=""
GOOS="linux"
GOPATH="/opt/go/path"
GOPRIVATE=""
GOPROXY="https://proxy.golang.org,direct"
GOROOT="/home/user/.gimme/versions/go"
GOSUMDB="sum.golang.org"
GOTMPDIR=""
GOTOOLDIR="/home/user/.gimme/versions/go/pkg/tool/linux_amd64"
GCCGO="gccgo"
AR="ar"
CC="gcc"
CXX="g++"
CGO_ENABLED="1"
GOMOD="/home/user/go-test/go.mod"
CGO_CFLAGS="-g -O2"
CGO_CPPFLAGS=""
CGO_CXXFLAGS="-g -O2"
CGO_FFLAGS="-g -O2"
CGO_LDFLAGS="-g -O2"
PKG_CONFIG="pkg-config"
GOGCCFLAGS="-fPIC -m64 -pthread -fmessage-length=0 -fdebug-prefix-map=/tmp/go-build146632005=/tmp/go-build -gno-record-gcc-switches"

What did you do?

Call t.Cleanup from inside of a cleanup function,

package main

import (
	"fmt"
	"testing"
)

func TestCleanup(t *testing.T) {
	t.Cleanup(func() {
		fmt.Println("cleanup initial")
		t.Cleanup(func() {
			fmt.Println("nested cleanup")
		})
	})

	fmt.Println("run test")
}

What did you expect to see?

Either the newly added Cleanup function to be run immediately after the initial clean up (to respect LIFO order) or for the Cleanup call to cause the test to be marked as failed.

What did you see instead?

The nested cleanup function is ignored silently,

=== RUN   TestCleanup
run test
cleanup initial
--- PASS: TestCleanup (0.00s)
PASS
ok  	command-line-arguments	0.004s

[seankhliao]

I believe this is a misuse of t.Cleanup, your second call is only registered when the first one is run (at the end of the tests) and not at the beginning of the test

[cagedmantis]

This does seem like a misuse of t.Cleanup. Silently failing seems odd though.

/cc @mpvl

[ianlancetaylor]

CC @rogpeppe

[ianlancetaylor]

I'll send a CL.

[gopherbot]

Change https://golang.org/cl/251457 mentions this issue: testing: run a Cleanup registered by a Cleanup