Instead of walking paths ourselves, just let Go's packages library do
it. This is a slight CLI change - it wants "./foo" rather than "foo".
This also flagged a few things which seem to be legit failures.
Prior to this it would download Go, setup the environment, then (maybe)
download Go again.
I renamed verify_go_version to be internal and fixed all callers.
This runs much faster than before. This change removes all of the
async status output because all of the compute time is spent inside
go/packages, with no opportunity to update the status.
Adds testdata code to prove it fails when expected.
Automatic merge from submit-queue. If you want to cherry-pick this change to another branch, please follow the instructions <a href="https://github.com/kubernetes/community/blob/master/contributors/devel/cherry-picks.md">here</a>.
Update all script shebangs to use /usr/bin/env interpreter instead of /bin/interpreter
This is required to support systems where bash doesn't reside in /bin (such as NixOS, or the *BSD family) and allow users to specify a different interpreter version through $PATH manipulation.
https://www.cyberciti.biz/tips/finding-bash-perl-python-portably-using-env.html
```release-note
Use /usr/bin/env in all script shebangs to increase portability.
```
Most of the time spent compiling is spent optimizing and linking
binary code. Most errors occur at the syntax or semantic (type) layers.
Go's compiler is importable as a normal package, so we can do fast
syntax and type checking for the 10 platforms we build on.
This currently takes ~6 minutes of CPU time (parallelized).
This makes presubmit cross builds superfluous, since it should catch
most cross-build breaks (generally Unix and 64-bit assumptions).
Example output:
$ time go run test/typecheck/main.go
type-checking: linux/amd64, windows/386, darwin/amd64, linux/arm, linux/386, windows/amd64, linux/arm64, linux/ppc64le, linux/s390x, darwin/386
ERROR(windows/amd64) pkg/proxy/ipvs/proxier.go:1708:27: ENXIO not declared by package unix
ERROR(windows/386) pkg/proxy/ipvs/proxier.go:1708:27: ENXIO not declared by package unix
real 0m45.083s
user 6m15.504s
sys 1m14.000s
