Invalid version detection when tests present

[alexdyukov]

Hey!

There is an invalid version detected with mingo on repo with tests . If i run go test by 1.16 version its work OK:

$ docker run -w /go/src -v .:/go/src golang:1.16 go test ./...
ok      github.com/alexdyukov/httpencoder   0.004s

but mingo tell me to upgrade go.mod up to 1.18 because testing.MainStart found:

$ go run github.com/bobg/mingo/cmd/mingo@latest -tests -check -v
/mnt/src/httpencoder/httpencoder.go:14:14: 7 ("context".Context)
/home/user/.cache/go-build/da/da4e65ca611572657c91072fb1a91ebac4181a9803104dff938df30632d6743c-d:57:7: 18 ("testing".MainStart)
Error scanning directory: go.mod declares version 1.16 but computed minimum is 1.18 [/home/user/.cache/go-build/da/da4e65ca611572657c91072fb1a91ebac4181a9803104dff938df30632d6743c-d:57:7: 18 ("testing".MainStart)]
exit status 1

[bobg]

Thank you for the report!

I don't have a convenient way to test my fix, would you like to help? Simply run the same command as you did above, but replace @latest with @3ed5fa8 (the commit containing the fix). Does mingo produce the right output in that case?

[alexdyukov]

Sure. Same error:

$ go run github.com/bobg/mingo/cmd/mingo@3ed5fa8 -tests -check -v
go: downloading github.com/bobg/mingo v0.9.7-0.20240705165823-3ed5fa8c1205
warning: GOPATH set to GOROOT (/home/user/go) has no effect
/mnt/c/Users/Lenovo/Downloads/FTA/src/httpencoder/decode.go:9:25: 3 ("sync".Pool)
/mnt/c/Users/Lenovo/Downloads/FTA/src/httpencoder/httpencoder.go:15:14: 7 ("context".Context)
/home/user/.cache/go-build/0e/0e70fa0823bc74d50197606763f245c57182455839ab3766d19b7bd229a94a14-d:57:7: 18 ("testing".MainStart)
Error scanning directory: go.mod declares version 1.16 but computed minimum is 1.18 [/home/user/.cache/go-build/0e/0e70fa0823bc74d50197606763f245c57182455839ab3766d19b7bd229a94a14-d:57:7: 18 ("testing".MainStart)]
exit status 1
$ go env | grep CACHE
warning: GOPATH set to GOROOT (/home/user/go) has no effect
GOCACHE='/home/user/.cache/go-build'
GOMODCACHE='/home/user/go/pkg/mod'

[alexdyukov]

I run go install and got same error:

$ go install github.com/bobg/mingo/cmd/mingo@latest
warning: GOPATH set to GOROOT (/home/user/go) has no effect
$ mingo -tests -check -v
/mnt/c/Users/Lenovo/Downloads/FTA/src/httpencoder/decode.go:9:25: 3 ("sync".Pool)
/mnt/c/Users/Lenovo/Downloads/FTA/src/httpencoder/httpencoder.go:15:14: 7 ("context".Context)
/home/user/.cache/go-build/0e/0e70fa0823bc74d50197606763f245c57182455839ab3766d19b7bd229a94a14-d:57:7: 18 ("testing".MainStart)
Error scanning directory: go.mod declares version 1.16 but computed minimum is 1.18 [/home/user/.cache/go-build/0e/0e70fa0823bc74d50197606763f245c57182455839ab3766d19b7bd229a94a14-d:57:7: 18 ("testing".MainStart)]

[alexdyukov]

I think os.Getenv() not the proper way to get GOCACHE env variable, cause i did not set it in my command line:

user@DESKTOP-D8T7N02:~/src/httpencoder$ go env | grep CACHE
warning: GOPATH set to GOROOT (/home/user/go) has no effect
GOCACHE='/home/user/.cache/go-build'
GOMODCACHE='/home/user/go/pkg/mod'
user@DESKTOP-D8T7N02:~/src/httpencoder$ echo $GOCACHE

user@DESKTOP-D8T7N02:~/src/httpencoder$

[bobg]

Derp, of course! Sorry, and thank you again.

Here is a new commit that should work better 🤞: 44c0f53

[alexdyukov]

Nice, error is gone, but mingo computes wrong version now. Lets close this issue and open another one?

The right version should be 1.16 (i do rewrite go.mod file of course):

user@DESKTOP-D8T7N02:~/src/httpencoder$ docker run -w /go/src -v .:/go/src golang:1.16 go test ./...
ok      github.com/alexdyukov/httpencoder       0.007s
user@DESKTOP-D8T7N02:~/src/httpencoder$ docker run -w /go/src -v .:/go/src golang:1.15 go test ./...
# github.com/alexdyukov/httpencoder
./decode.go:55:18: undefined: io.NopCloser
FAIL    github.com/alexdyukov/httpencoder [build failed]
FAIL

but now it decodes as 1.7:

user@DESKTOP-D8T7N02:~/src/httpencoder$ go run github.com/bobg/mingo/cmd/mingo@44c0f53 -tests -check -v
warning: GOPATH set to GOROOT (/home/user/go) has no effect
/mnt/c/Users/Lenovo/Downloads/FTA/src/httpencoder/decode.go:9:25: 3 ("sync".Pool)
/mnt/c/Users/Lenovo/Downloads/FTA/src/httpencoder/httpencoder.go:15:14: 7 ("context".Context)
Error scanning directory: go.mod declares version 1.16 but computed minimum is 1.7 [/mnt/c/Users/Lenovo/Downloads/FTA/src/httpencoder/httpencoder.go:15:14: 7 ("context".Context)]
exit status 1

[bobg]

Thank you again for your help!

What is in your code or dependencies that makes you think the answer should be 1.16? (The version declaration in go.mod does not count.)

[bobg]

Oh never mind - I see it's io.NopCloser.

No need for a new issue, I will keep investigating. Meanwhile, it would help me if you can easily share a minimal reproducible case.

[alexdyukov]

system library uses:

sync.Pool           go1.3
bytes.Buffer{}          go1.0
context.Context         go1.7
io.Writer           go1.0
http.Request.Header.Get     go1.0
http.Handler.ServeHTTP      go1.0
bytes.Buffer.Bytes()        go1.0
http.DetectContentType      go1.0
http.ResponseWriter.WriteHeader go1.0
http.Error          go1.0
io.NopCloser            go1.16

by cmd output i see mingo detects context.Context and sync.Pool, but missing calling io.NopCloser. I make a test code with same error. Feel free debugging with it:

user@DESKTOP-D8T7N02:~/src/benchmarks$ go run github.com/bobg/mingo/cmd/mingo@44c0f53 -check -v
warning: GOPATH set to GOROOT (/home/user/go) has no effect
/mnt/c/Users/Lenovo/Downloads/FTA/src/benchmarks/main.go:10:64: 1 (function body with no final return statement)
Error scanning directory: go.mod declares version 1.18 but computed minimum is 1.1 [/mnt/c/Users/Lenovo/Downloads/FTA/src/benchmarks/main.go:10:64: 1 (function body with no final return statement)]
exit status 1
user@DESKTOP-D8T7N02:~/src/benchmarks$ cat main.go
package main

import (
        "bytes"
        "fmt"
        "io"
)

func main() {
        fmt.Println(len(customReadAll(io.NopCloser(&bytes.Buffer{}))))
}

func customReadAll(reader io.Reader) []byte {
        buf := make([]byte, 100)
        retVal := []byte{}
        for {
                n, err := reader.Read(buf)

                retVal = append(retVal, buf...)
                buf = buf[:0]

                if n < 100 || err != nil {
                        return retVal
                }
        }

        return nil
}

[bobg]

Eureka - your example helped me find that mingo was overlooking the arguments to builtin functions like len. Thank you for your help!