all: CI's enforcement of clean go generate is lacking

[Jorropo]

Go version

go version devel go1.24-110ab1aaf4 Sat Dec 21 08:22:08 2024 -0800 linux/amd64

Output of go env in your module/workspace:

AR='ar'
CC='gcc'
CGO_CFLAGS='-O2 -g'
CGO_CPPFLAGS=''
CGO_CXXFLAGS='-O2 -g'
CGO_ENABLED='1'
CGO_FFLAGS='-O2 -g'
CGO_LDFLAGS='-O2 -g'
CXX='g++'
GCCGO='gccgo'
GO111MODULE=''
GOAMD64='v3'
GOARCH='amd64'
GOAUTH='netrc'
GOBIN=''
GOCACHE='/tmp/go-build'
GODEBUG=''
GOENV='/home/hugo/.config/go/env'
GOEXE=''
GOEXPERIMENT=''
GOFIPS140='off'
GOFLAGS=''
GOGCCFLAGS='-fPIC -m64 -pthread -Wl,--no-gc-sections -fmessage-length=0 -ffile-prefix-map=/tmp/go-build610608568=/tmp/go-build -gno-record-gcc-switches'
GOHOSTARCH='amd64'
GOHOSTOS='linux'
GOINSECURE=''
GOMOD='/home/hugo/k/go/src/go.mod'
GOMODCACHE='/home/hugo/go/pkg/mod'
GONOPROXY=''
GONOSUMDB=''
GOOS='linux'
GOPATH='/home/hugo/go'
GOPRIVATE=''
GOPROXY='https://proxy.golang.org,direct'
GOROOT='/home/hugo/k/go'
GOSUMDB='sum.golang.org'
GOTELEMETRY='local'
GOTELEMETRYDIR='/home/hugo/.config/go/telemetry'
GOTMPDIR=''
GOTOOLCHAIN='local'
GOTOOLDIR='/home/hugo/k/go/pkg/tool/linux_amd64'
GOVCS=''
GOVERSION='devel go1.24-110ab1aaf4 Sat Dec 21 08:22:08 2024 -0800'
GOWORK=''
PKG_CONFIG='pkg-config'

What did you do?

In the go repo:

cd src
./make.bash
cd internal/goexperiment/ && go generate .
git status

What did you see happen?

On branch master
Your branch is up to date with 'origin/master'.

Untracked files:
  (use "git add <file>..." to include in what will be committed)
	exp_synctest_off.go
	exp_synctest_on.go

nothing added to commit but untracked files present (use "git add" to track)

What did you expect to see?

On branch master
Your branch is up to date with 'origin/master'.

nothing to commit, working tree clean

[gabyhelp]

Related Issues

• x/tools/internal/modindex: TestIncremental failures #70121 (closed)
• test: "buildrundir", "builddir" directives leave untracked go_asm.h files #28781 (closed)
• cmd/go: git shallow fetches broken at CL 556358 #66147 (closed)
• cmd/go: go1.11rc2 failed test: FAIL: TestScript/mod_get_commit #27170 (closed)
• go.mod shows changed in Git on Windows #32491 (closed)
• cmd/go: tests fail when GOROOT is stale #48698 (closed)
• x/build/cmd/gitmirror: fails if global git config has safe.bareRepository set to 'explicit' #66202 (closed)
• Untracked cmd/go/zosarch.go, cmd/go/zdefaultcc.go appear #19053 (closed)
• cmd/go/internal/script: fix build tags of isETXTBSY #67356 (closed)

Related Discussions

• 'go build' over writing source code.

_{(Emoji vote if this was helpful or unhelpful; more detailed feedback welcome in this discussion.)}

[Jorropo]

cc @neild ¿ 76e4efd ?

[gopherbot]

Change https://go.dev/cl/638355 mentions this issue: internal/goexperiment: run go generate for synctest

[Jorropo]

I am opening this issue to question our testing procedure around go generate, this is the second time I was working on something and I first need to fix go generate: https://go-review.googlesource.com/c/go/+/603995

It looks to me like we lack some go generate none diff checks in CI even for slowbots.

[dmitshur]

Some packages have their own test that checks that generated files are up to date (for example, see here and here). Generally, tests in GOROOT shouldn't write to GOROOT itself, so these tests take care not to do that, and instead make that functionality optionally available via a -fix/-write flag.

There's also the cmd/internal/moddeps test which copies the entire tree to a temporary directory to make it easy to check for inconsistencies and report them, without writing to GOROOT itself. As the name implies, these tests are intended to check things that need to be regenerated and/or kept in sync after pulling in newer versions of dependencies. It can be easily added there. It'd be a bit odd to check these things there, but the advantage is that it's effortless and wouldn't require copying the tree an additional time.

[gopherbot]

Change https://go.dev/cl/638582 mentions this issue: cmd/internal/moddeps: check that goexperiment is generated