kubernetes/test/typecheck
Ryan Hitchman dd40e612dd Add test/typecheck, a fast typecheck for all build platforms.
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
2018-02-27 13:53:32 -08:00
..
srcimporter Add test/typecheck, a fast typecheck for all build platforms. 2018-02-27 13:53:32 -08:00
BUILD Add test/typecheck, a fast typecheck for all build platforms. 2018-02-27 13:53:32 -08:00
main_test.go Add test/typecheck, a fast typecheck for all build platforms. 2018-02-27 13:53:32 -08:00
main.go Add test/typecheck, a fast typecheck for all build platforms. 2018-02-27 13:53:32 -08:00
README Add test/typecheck, a fast typecheck for all build platforms. 2018-02-27 13:53:32 -08:00

Typecheck does cross-platform typechecking of source code for all Go build
platforms.

The primary benefit is speed: a full Kubernetes cross-build takes 20 minutes
and >40GB of RAM, while this takes under 2 minutes and <8GB of RAM.

It uses Go's built-in parsing and typechecking libraries (go/parser and
go/types), which unfortunately are not what the go compiler uses. Occasional
mismatches will occur, but overall they correspond closely.

Failures can be ignored if they don't block the build:

Things go/types errors on that go build doesn't:
  True errors (according to the spec):
    These should be fixed whenever possible. Ignore if a fix isn't possible
    or is in progress (e.g., vendored code).
    - unused variables in closures
  False errors:
    These should be ignored and reported upstream if applicable.
    - type checking mismatches between staging and generated types
Things go build fails on that we don't:
  Please send examples of this to rmmh@ and extend this list.
  - CGo errors, including syntax and linker errors.