cmd/go: fails to run test in generics-using package that has a dep not in go.mod #59980
Closed as not planned
Description
What version of Go are you using (go version)?
Both:
- go version go1.20.4 darwin/arm64
- go version devel go1.21-5c51e9f45b Thu May 4 18:03:04 2023 +0000 darwin/arm64
Does this issue reproduce with the latest release?
Yes
What did you do?
I tried to run tests of a package in another module, where my current module didn't have those test deps in go.mod.
You get weird -lang mismatches (is it synthesizing some fake module behind the scenes and not filling something out?) instead of either working or failing nicely.
Repro at https://github.com/bradfitz/go-test-bug-repro
$ go version
go version go1.20.4 darwin/arm64
$ go test tailscale.com/net/dns/resolver
# github.com/miekg/dns
embedding interface element ~[]string requires go1.18 or later (-lang was set to go1.16; check go.mod)
../go/pkg/mod/github.com/miekg/[email protected]/msg.go:549:12: type parameter requires go1.18 or later (-lang was set to go1.16; check go.mod)
../go/pkg/mod/github.com/miekg/[email protected]/msg.go:549:14: embedding interface element ~[]byte | ~string requires go1.18 or later (-lang was set to go1.16; check go.mod)
../go/pkg/mod/github.com/miekg/[email protected]/msg.go:553:16: type parameter requires go1.18 or later (-lang was set to go1.16; check go.mod)
../go/pkg/mod/github.com/miekg/[email protected]/types.go:1605:17: type parameter requires go1.18 or later (-lang was set to go1.16; check go.mod)
../go/pkg/mod/github.com/miekg/[email protected]/types.go:1605:19: predeclared any requires go1.18 or later (-lang was set to go1.16; check go.mod)
../go/pkg/mod/github.com/miekg/[email protected]/types.go:1605:26: embedding interface element ~[]E requires go1.18 or later (-lang was set to go1.16; check go.mod)
../go/pkg/mod/github.com/miekg/[email protected]/clientconfig.go:71:25: implicit function instantiation requires go1.18 or later (-lang was set to go1.16; check go.mod)
../go/pkg/mod/github.com/miekg/[email protected]/defaults.go:211:12: implicit function instantiation requires go1.18 or later (-lang was set to go1.16; check go.mod)
../go/pkg/mod/github.com/miekg/[email protected]/edns.go:523:63: implicit function instantiation requires go1.18 or later (-lang was set to go1.16; check go.mod)
../go/pkg/mod/github.com/miekg/[email protected]/edns.go:523:63: too many errors
FAIL tailscale.com/net/dns/resolver [build failed]
FAIL
$ go get github.com/miekg/[email protected] # <---- the workaround
$ go test tailscale.com/net/dns/resolver
ok tailscale.com/net/dns/resolver 0.160s
$ go mod tidy
$ go test tailscale.com/net/dns/resolver
# github.com/miekg/dns
embedding interface element ~[]string requires go1.18 or later (-lang was set to go1.16; check go.mod)
../go/pkg/mod/github.com/miekg/[email protected]/msg.go:549:12: type parameter requires go1.18 or later (-lang was set to go1.16; check go.mod)
../go/pkg/mod/github.com/miekg/[email protected]/msg.go:549:14: embedding interface element ~[]byte | ~string requires go1.18 or later (-lang was set to go1.16; check go.mod)
../go/pkg/mod/github.com/miekg/[email protected]/msg.go:553:16: type parameter requires go1.18 or later (-lang was set to go1.16; check go.mod)
../go/pkg/mod/github.com/miekg/[email protected]/types.go:1605:17: type parameter requires go1.18 or later (-lang was set to go1.16; check go.mod)
../go/pkg/mod/github.com/miekg/[email protected]/types.go:1605:19: predeclared any requires go1.18 or later (-lang was set to go1.16; check go.mod)
../go/pkg/mod/github.com/miekg/[email protected]/types.go:1605:26: embedding interface element ~[]E requires go1.18 or later (-lang was set to go1.16; check go.mod)
../go/pkg/mod/github.com/miekg/[email protected]/clientconfig.go:71:25: implicit function instantiation requires go1.18 or later (-lang was set to go1.16; check go.mod)
../go/pkg/mod/github.com/miekg/[email protected]/defaults.go:211:12: implicit function instantiation requires go1.18 or later (-lang was set to go1.16; check go.mod)
../go/pkg/mod/github.com/miekg/[email protected]/edns.go:523:63: implicit function instantiation requires go1.18 or later (-lang was set to go1.16; check go.mod)
../go/pkg/mod/github.com/miekg/[email protected]/edns.go:523:63: too many errors
FAIL tailscale.com/net/dns/resolver [build failed]
FAIL