cmd/go: 'go test all' tests unused std lib packages when using modules

[alexedwards]

Based on #26317 (comment) and the documentation for all in go help packages, when using modules I expect go test all to test only the standard library packages which actually get built into the packages in a module.

It appears to be testing all standard library packages.

System details

go version go1.12.1 linux/amd64
GOARCH="amd64"
GOBIN=""
GOCACHE="/home/alex/.cache/go-build"
GOEXE=""
GOFLAGS=""
GOHOSTARCH="amd64"
GOHOSTOS="linux"
GOOS="linux"
GOPATH="/home/alex/go"
GOPROXY=""
GORACE=""
GOROOT="/usr/local/go"
GOTMPDIR=""
GOTOOLDIR="/usr/local/go/pkg/tool/linux_amd64"
GCCGO="gccgo"
CC="gcc"
CXX="g++"
CGO_ENABLED="1"
GOMOD=""
GOROOT/bin/go version: go version go1.12.1 linux/amd64
GOROOT/bin/go tool compile -V: compile version go1.12.1
uname -sr: Linux 4.18.0-16-generic
Distributor ID:	Ubuntu
Description:	Ubuntu 18.10
Release:	18.10
Codename:	cosmic
/lib/x86_64-linux-gnu/libc.so.6: GNU C Library (Ubuntu GLIBC 2.28-0ubuntu1) stable release version 2.28.
gdb --version: GNU gdb (Ubuntu 8.2-0ubuntu1) 8.2

What did you do?

$ mkdir /tmp/ta
$ cd /tmp/ta
$ go mod init example.com/ta
$ cat >main.go <<EOF
> package main
> 
> import "fmt"
> 
> func main() {
>         fmt.Println("hello")
> }
> EOF
$ go test all

What did you expect to see?

From go help packages:

When using modules, "all" expands to all packages in the main module and their dependencies, including dependencies needed by tests of any of those.

So I would expect to see go test all test the following standard library packages only (based on the output of go list -deps):

errors
internal/cpu
unsafe
math/bits
math
internal/bytealg
runtime/internal/atomic
runtime/internal/sys
runtime/internal/math
runtime
unicode/utf8
strconv
internal/race
sync/atomic
sync
unicode
reflect
sort
internal/fmtsort
io
syscall
time
internal/poll
internal/syscall/unix
internal/testlog
os
fmt

What did you see instead?

Running go test all appears to unnecessarily test additional standard library packages:

$ go test all
ok  	bufio	0.119s
ok  	bytes	2.426s
ok  	compress/bzip2	0.086s
ok  	compress/flate	12.565s
ok  	compress/gzip	0.047s
ok  	compress/lzw	0.086s
ok  	compress/zlib	1.020s
ok  	container/heap	0.021s
ok  	container/list	0.023s
ok  	context	2.372s
ok  	crypto	0.014s
ok  	crypto/aes	0.033s
ok  	crypto/cipher	0.299s
ok  	crypto/des	0.016s
ok  	crypto/dsa	11.754s
ok  	crypto/ecdsa	4.906s
...

[agnivade]

@bcmills @jayconrod

[bcmills]

Note from the “system details” section of the report:

GOMOD=""

That indicates that the go command is not, in fact, in module mode. What happens if you run GO111MODULE=on go test all?

[bcmills]

CC @jayconrod

go list -deps does not include the dependencies of tests of dependencies. However, all explicitly does: that accounts for the observed difference.

example.com$ go1.12.1 mod init example.com
go: creating new go.mod: module example.com

example.com$ cat >main.go <<EOF
package main

import "fmt"

func main() {
        fmt.Println("hello")
}
EOF

example.com$ go1.12.1 list -deps >deps.txt

example.com$ go1.12.1 list -deps -test $(<deps.txt) | sort -u
bufio
bufio [internal/cpu.test]
bufio [runtime.test]
bufio [sync.test]
bytes
bytes [internal/cpu.test]
bytes [runtime.test]
bytes [sync.test]
compress/flate
compress/flate [fmt.test]
compress/flate [internal/cpu.test]
compress/flate [internal/fmtsort.test]
compress/flate [internal/poll.test]
compress/flate [math/bits.test]
compress/flate [math.test]
compress/flate [os.test]
compress/flate [reflect.test]
compress/flate [runtime.test]
compress/flate [sort.test]
compress/flate [strconv.test]
compress/flate [sync.test]
compress/flate [syscall.test]
compress/flate [time.test]
compress/gzip
compress/gzip [fmt.test]
compress/gzip [internal/cpu.test]
compress/gzip [internal/fmtsort.test]
compress/gzip [internal/poll.test]
compress/gzip [math/bits.test]
compress/gzip [math.test]
compress/gzip [os.test]
compress/gzip [reflect.test]
compress/gzip [runtime.test]
compress/gzip [sort.test]
compress/gzip [strconv.test]
compress/gzip [sync.test]
compress/gzip [syscall.test]
compress/gzip [time.test]
context
context [fmt.test]
context [internal/cpu.test]
context [internal/fmtsort.test]
context [internal/poll.test]
context [math/bits.test]
context [math.test]
context [os.test]
context [reflect.test]
context [runtime.test]
context [sort.test]
context [strconv.test]
context [sync.test]
context [syscall.test]
context [time.test]
crypto
crypto/aes [runtime.test]
crypto/cipher [runtime.test]
crypto/internal/subtle
crypto/rand [runtime.test]
crypto/sha1
crypto/subtle
encoding
encoding/base64
encoding/base64 [reflect.test]
encoding/binary
encoding/binary [internal/cpu.test]
encoding/binary [math/bits.test]
encoding/binary [math.test]
encoding/binary [reflect.test]
encoding/binary [runtime.test]
encoding/binary [strconv.test]
encoding/binary [sync.test]
encoding/gob [time.test]
encoding/json [reflect.test]
encoding/json [time.test]
errors
errors.test
errors_test [errors.test]
example.com
flag
flag [fmt.test]
flag [internal/cpu.test]
flag [internal/fmtsort.test]
flag [internal/poll.test]
flag [math/bits.test]
flag [math.test]
flag [os.test]
flag [reflect.test]
flag [runtime.test]
flag [sort.test]
flag [strconv.test]
flag [sync.test]
flag [syscall.test]
flag [time.test]
fmt
fmt [fmt.test]
fmt [internal/cpu.test]
fmt [internal/fmtsort.test]
fmt [internal/poll.test]
fmt [math/bits.test]
fmt [math.test]
fmt [os.test]
fmt [reflect.test]
fmt [runtime.test]
fmt [sort.test]
fmt [strconv.test]
fmt [sync.test]
fmt [syscall.test]
fmt.test
fmt_test [fmt.test]
fmt [time.test]
go/ast [reflect.test]
go/ast [runtime.test]
go/build [runtime.test]
go/doc [runtime.test]
go/parser [runtime.test]
go/scanner [reflect.test]
go/scanner [runtime.test]
go/token [reflect.test]
go/token [runtime.test]
hash
hash/crc32
hash/crc32 [internal/cpu.test]
hash/crc32 [runtime.test]
hash/crc32 [sync.test]
hash [internal/cpu.test]
hash [runtime.test]
hash [sync.test]
internal/bytealg
internal/bytealg [internal/cpu.test]
internal/cpu
internal/cpu [internal/cpu.test]
internal/cpu.test
internal/cpu_test [internal/cpu.test]
internal/fmtsort
internal/fmtsort [internal/cpu.test]
internal/fmtsort [internal/fmtsort.test]
internal/fmtsort [math/bits.test]
internal/fmtsort [math.test]
internal/fmtsort [reflect.test]
internal/fmtsort [runtime.test]
internal/fmtsort [sort.test]
internal/fmtsort [strconv.test]
internal/fmtsort [sync.test]
internal/fmtsort.test
internal/fmtsort_test [internal/fmtsort.test]
internal/goroot [runtime.test]
internal/nettrace
internal/poll
internal/poll [internal/cpu.test]
internal/poll [internal/poll.test]
internal/poll [runtime.test]
internal/poll [sync.test]
internal/poll [syscall.test]
internal/poll.test
internal/poll_test [internal/poll.test]
internal/poll [time.test]
internal/race
internal/singleflight
internal/singleflight [runtime.test]
internal/syscall/unix
internal/syscall/unix [internal/cpu.test]
internal/syscall/unix [runtime.test]
internal/syscall/unix [sync.test]
internal/syscall/unix [syscall.test]
internal/testenv [internal/cpu.test]
internal/testenv [os.test]
internal/testenv [runtime.test]
internal/testenv [sort.test]
internal/testenv [sync.test]
internal/testenv [syscall.test]
internal/testlog
internal/x/net/dns/dnsmessage
io
io [internal/cpu.test]
io/ioutil
io/ioutil [internal/cpu.test]
io/ioutil [internal/poll.test]
io/ioutil [math/bits.test]
io/ioutil [math.test]
io/ioutil [os.test]
io/ioutil [reflect.test]
io/ioutil [runtime.test]
io/ioutil [sort.test]
io/ioutil [strconv.test]
io/ioutil [sync.test]
io/ioutil [syscall.test]
io/ioutil [time.test]
io [runtime.test]
io [sync.test]
io.test
io_test [io.test]
log
log [fmt.test]
log [os.test]
log [runtime.test]
log [strconv.test]
math
math/big [runtime.test]
math/big [time.test]
math/bits
math/bits [math/bits.test]
math/bits.test
math/bits_test [math/bits.test]
math/cmplx
math [internal/cpu.test]
math [math/bits.test]
math [math.test]
math/rand
math/rand [runtime.test]
math/rand [sync.test]
math.test
math_test [math.test]
net [runtime.test]
net [syscall.test]
net/url [runtime.test]
os
os/exec [internal/cpu.test]
os/exec [os.test]
os/exec [runtime.test]
os/exec [sort.test]
os/exec [sync.test]
os/exec [syscall.test]
os [internal/cpu.test]
os [internal/poll.test]
os [os.test]
os [runtime.test]
os/signal [os.test]
os/signal [syscall.test]
os [sync.test]
os [syscall.test]
os.test
os_test [os.test]
os [time.test]
os/user [syscall.test]
path/filepath
path/filepath [internal/cpu.test]
path/filepath [internal/poll.test]
path/filepath [math/bits.test]
path/filepath [math.test]
path/filepath [os.test]
path/filepath [reflect.test]
path/filepath [runtime.test]
path/filepath [sort.test]
path/filepath [strconv.test]
path/filepath [sync.test]
path/filepath [syscall.test]
path/filepath [time.test]
path [runtime.test]
reflect
reflect [internal/cpu.test]
reflect [math/bits.test]
reflect [math.test]
reflect [reflect.test]
reflect [runtime.test]
reflect [strconv.test]
reflect [sync.test]
reflect.test
reflect_test [reflect.test]
regexp
regexp [internal/cpu.test]
regexp [math/bits.test]
regexp [math.test]
regexp [reflect.test]
regexp [runtime.test]
regexp [sort.test]
regexp [strconv.test]
regexp [sync.test]
regexp/syntax
regexp/syntax [internal/cpu.test]
regexp/syntax [math/bits.test]
regexp/syntax [math.test]
regexp/syntax [reflect.test]
regexp/syntax [runtime.test]
regexp/syntax [sort.test]
regexp/syntax [strconv.test]
regexp/syntax [sync.test]
runtime
runtime/cgo
runtime/debug
runtime/debug [internal/cpu.test]
runtime/debug [internal/poll.test]
runtime/debug [math/bits.test]
runtime/debug [math.test]
runtime/debug [os.test]
runtime/debug [reflect.test]
runtime/debug [runtime.test]
runtime/debug [sort.test]
runtime/debug [strconv.test]
runtime/debug [sync.test]
runtime/debug [syscall.test]
runtime/debug [time.test]
runtime/internal/atomic
runtime/internal/atomic.test
runtime/internal/atomic_test [runtime/internal/atomic.test]
runtime [internal/cpu.test]
runtime/internal/math
runtime/internal/math.test
runtime/internal/math_test [runtime/internal/math.test]
runtime/internal/sys
runtime/internal/sys.test
runtime/internal/sys_test [runtime/internal/sys.test]
runtime/pprof
runtime/pprof [fmt.test]
runtime/pprof [internal/cpu.test]
runtime/pprof [internal/fmtsort.test]
runtime/pprof [internal/poll.test]
runtime/pprof [math/bits.test]
runtime/pprof [math.test]
runtime/pprof [os.test]
runtime/pprof [reflect.test]
runtime/pprof [runtime.test]
runtime/pprof [sort.test]
runtime/pprof [strconv.test]
runtime/pprof [sync.test]
runtime/pprof [syscall.test]
runtime/pprof [time.test]
runtime [runtime.test]
runtime.test
runtime_test [runtime.test]
runtime/trace
runtime/trace [fmt.test]
runtime/trace [internal/cpu.test]
runtime/trace [internal/fmtsort.test]
runtime/trace [internal/poll.test]
runtime/trace [math/bits.test]
runtime/trace [math.test]
runtime/trace [os.test]
runtime/trace [reflect.test]
runtime/trace [runtime.test]
runtime/trace [sort.test]
runtime/trace [strconv.test]
runtime/trace [sync.test]
runtime/trace [syscall.test]
runtime/trace [time.test]
sort
sort [internal/cpu.test]
sort [math/bits.test]
sort [math.test]
sort [reflect.test]
sort [runtime.test]
sort [sort.test]
sort [strconv.test]
sort [sync.test]
sort.test
sort_test [sort.test]
strconv
strconv [internal/cpu.test]
strconv [math/bits.test]
strconv [math.test]
strconv [strconv.test]
strconv.test
strconv_test [strconv.test]
strings
strings [internal/cpu.test]
strings [runtime.test]
strings [sync.test]
sync
sync/atomic
sync/atomic.test
sync/atomic_test [sync/atomic.test]
sync [internal/cpu.test]
sync [runtime.test]
sync [sync.test]
sync.test
sync_test [sync.test]
syscall
syscall [internal/cpu.test]
syscall [runtime.test]
syscall [sync.test]
syscall [syscall.test]
syscall.test
syscall_test [syscall.test]
testing
testing [fmt.test]
testing [internal/cpu.test]
testing [internal/fmtsort.test]
testing [internal/poll.test]
testing/internal/testdeps
testing/internal/testdeps [fmt.test]
testing/internal/testdeps [internal/cpu.test]
testing/internal/testdeps [internal/fmtsort.test]
testing/internal/testdeps [internal/poll.test]
testing/internal/testdeps [math/bits.test]
testing/internal/testdeps [math.test]
testing/internal/testdeps [os.test]
testing/internal/testdeps [reflect.test]
testing/internal/testdeps [runtime.test]
testing/internal/testdeps [sort.test]
testing/internal/testdeps [strconv.test]
testing/internal/testdeps [sync.test]
testing/internal/testdeps [syscall.test]
testing/internal/testdeps [time.test]
testing/iotest [fmt.test]
testing [math/bits.test]
testing [math.test]
testing [os.test]
testing/quick [sync.test]
testing/quick [time.test]
testing [reflect.test]
testing [runtime.test]
testing [sort.test]
testing [strconv.test]
testing [sync.test]
testing [syscall.test]
testing [time.test]
text/tabwriter
text/tabwriter [internal/cpu.test]
text/tabwriter [runtime.test]
text/tabwriter [sync.test]
text/template/parse [runtime.test]
text/template [runtime.test]
time
time [internal/cpu.test]
time [runtime.test]
time [sync.test]
time [syscall.test]
time.test
time_test [time.test]
time [time.test]
unicode
unicode.test
unicode_test [unicode.test]
unicode/utf16
unicode/utf8
unicode/utf8.test
unicode/utf8_test [unicode/utf8.test]
unsafe

[alexedwards]

Ah, I see.

Thank you.