The version I'm using is go1.22.6.
To reproduce the issue, I created a repository. This repository does not
contain a go.mod, but it could still be imported. Since the modules within
the same repository can be used without placing a go.mod in each of them, I
mistakenly thought that an external module uploaded to GitHub also wouldn’t
need a go.mod.
What I tried to do was to import this external module in main.go and run it.
```
$ go mod tidy
go: finding module for package github.com/kitsne241/samplemod
go: found github.com/kitsne241/samplemod in github.com/kitsne241/samplemod
v0.0.0-20241023023417-c2f6a03a5a85
$ go run main.go
# github.com/kitsne241/samplemod
../../go/pkg/mod/github.com/kitsne241/samplemod@v0.0.0-20241023023417-c2f6a03a5a85/samplemod.go:4:6:
predeclared any requires go1.18 or later (-lang was set to go1.16; check
go.mod)
```
main.go
```
package main
import (
"log"
"github.com/kitsne241/samplemod"
)
func main() {
date := samplemod.Date{
Day: "Sunday",
}
log.Print(date)
}
```
go.mod
```
module sample
go 1.22.6
require github.com/kitsne241/samplemod v0.0.0-20241023023417-c2f6a03a5a85
```
I felt that just finding the error message difficult to understand wasn’t
enough to report it as a bug, so I posted here in case someone else had
experienced the same confusion.
Thanks,
2024年10月23日水曜日 2:01:56 UTC+9 Ian Lance Taylor:
> On Tue, Oct 22, 2024 at 8:39 AM rojiu <azure...@gmail.com> wrote:
> >
> > I ran into this error when trying to create a module with a single Go
> file and import it from GitHub:
> >
> > ```
> > predeclared any requires go1.18 or later (-lang was set to go1.16; check
> go.mod)
> > ```
> >
> > After some digging, I learned that since Go 1.18, external modules need
> a go.mod file. Without one, the language spec defaults to Go 1.16. The
> tricky part is, it's not obvious at first glance that this error is caused
> by a missing go.mod file in the module you're trying to import. I was
> thrown off because the go.mod file in my main project had 'go 1.22.6' in
> it. It'll be helpful if the error message could specifically mention that
> it's looking for a go.mod file in the module being imported. What do you
> think?
>
> Thanks. Want to file a bug report at https://go.dev/issue ? Be sure
> to say exactly what you did and what Go version you are using. It's
> not immediately clear to me how you are importing a package that
> doesn't have a go.mod file.
>
> Ian
>
--
You received this message because you are subscribed to the Google Groups
"golang-nuts" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to golang-nuts+unsubscr...@googlegroups.com.
To view this discussion on the web visit
https://groups.google.com/d/msgid/golang-nuts/2283f081-d8ba-4653-b1ae-b51c2593c5b1n%40googlegroups.com.
