穿线工具抱怨档案头错误

Question

I am trying to use go generate/stringer (golang.org/x/tools/cmd/stringer) to generate String() methods on enums. I have problems, which I believe, are because of slightly different format of .a packages on different systems. I have this file:

package main

import (
    "math/rand"
)

//go:generate stringer -type=Foo
type Foo int;

const (
    FooPrime Foo = iota
    FooBis
)

func main() {
    //Just use rand anywhere, otherwise we get a compiler error
    rand.Seed(1)
}

Now if I run go generate example.go on my machine everything is all right: foo_string.go is created. However, on a test machine I get:

stringer: checking package: example.go:4:2: could not import math/rand (reading export data: /usr/lib64/go/pkg/linux_amd64/math/rand.a: go archive is missing __.PKGDEF)

Now, after some digging in the code I think that I get this error, because on my machine rand.a has the following header:

!<arch>
__.PKGDEF       0           0     0     644     2051   

` while on test machine it has the following header:

!<arch>
__.PKGDEF/      0           399   399   100644  2051  

`

I think that the crucial difference is slash after PKGDEFF. gcimporter refuses to process .a file, if it doesn't have __.PKGDEF header.

To check this, I edited manually gcimporter/exportdata.go and changed one of the line from this:

if name != "__.PKGDEF"

to this:

if name != "__.PKGDEF" && name != "__.PKGDEF\"

After this change (and compiling and installing everything) I was able to run go generate on example.go.

My questions are: why do I get this problem and how do I get rid of it (other then manually editing external library)?

Answer 1

What I can see from the spec for openSUSE's packaging they are disabling reinstallation of the standard library at updates. __.PKGDEF is a Go specific informational section, and some linker OpenSUSE has used has simply produced incompatible output.

There's nothing you can do except install a healthy Go from the official source.