如果编译器只是一个点发布版本太旧，有没有办法使Golang编译失败？

Question

Specifically, for our next software release, I want to make sure to catch a bug fix that was released in go 1.5.2; is there a way to make the build fail if our build server tries to build my code using Go 1.5.1 or earlier?

I know about Build Constraints, and I can see how I can add a build constraint of "go1.5" to make sure the "1.5 or greater" compiler is used, but "go1.5.2" doesn't work (it appears that build tags go1.5.1 and go1.5.2 are not defined.)

On a related note, I also can't find a way to dump out the build tags that apply for a build, and yet this seems to be a pretty useful thing to do.

Answer 1

You can use the -ldflags to pass the configured min golang build and check at init() time if the runtime matches the specified version.

package main

import "runtime"

// go run -ldflags "-X main.minGoVersion=go1.5.1" main.go

// from http://stackoverflow.com/questions/18409373/how-to-compare-two-version-number-strings-in-golang
func VersionOrdinal(version string) string {
    // ISO/IEC 14651:2011
    const maxByte = 1<<8 - 1
    vo := make([]byte, 0, len(version)+8)
    j := -1
    for i := 0; i < len(version); i++ {
        b := version[i]
        if '0' > b || b > '9' {
            vo = append(vo, b)
            j = -1
            continue
        }
        if j == -1 {
            vo = append(vo, 0x00)
            j = len(vo) - 1
        }
        if vo[j] == 1 && vo[j+1] == '0' {
            vo[j+1] = b
            continue
        }
        if vo[j]+1 > maxByte {
            panic("VersionOrdinal: invalid version")
        }
        vo = append(vo, b)
        vo[j]++
    }
    return string(vo)
}

var minGoVersion string

func init() {
    if minGoVersion == "" {
        panic("please pass  -ldflags \"-X main.minGoVersion=<version string> flag\"")
    }

    current := VersionOrdinal(runtime.Version())
    desired := VersionOrdinal(minGoVersion)
    if current < desired {
        panic("unsupported golang runtime " + current + " < " + desired)
    }
}

func main() {

}