cmd/go: "go generate" appears to be a silent no-op when given a missing package #60079
Description
What version of Go are you using (go version)?
$ go version go version devel go1.21-8d5065ce6e Tue May 9 01:28:10 2023 +0000 linux/amd64
Does this issue reproduce with the latest release?
Yes; appears to happen with 1.20.4 as well.
What operating system and processor architecture are you using (go env)?
go env Output
$ go env GO111MODULE='' GOARCH='amd64' GOBIN='' GOCACHE='/home/mvdan/.cache/go-build' GOENV='/home/mvdan/.config/go/env' GOEXE='' GOEXPERIMENT='' GOFLAGS='' GOHOSTARCH='amd64' GOHOSTOS='linux' GOINSECURE='' GOMODCACHE='/home/mvdan/go/pkg/mod' GONOPROXY='github.com/cue-unity' GONOSUMDB='github.com/cue-unity' GOOS='linux' GOPATH='/home/mvdan/go' GOPRIVATE='github.com/cue-unity' GOPROXY='https://proxy.golang.org,direct' GOROOT='/home/mvdan/tip' GOSUMDB='sum.golang.org' GOTMPDIR='' GOTOOLDIR='/home/mvdan/tip/pkg/tool/linux_amd64' GOVCS='' GOVERSION='devel go1.21-8d5065ce6e Tue May 9 01:28:10 2023 +0000' GCCGO='gccgo' GOAMD64='v3' AR='ar' CC='gcc' CXX='g++' CGO_ENABLED='1' GOMOD='/home/mvdan/tip/src/go.mod' GOWORK='' CGO_CFLAGS='-O2 -g' CGO_CPPFLAGS='' CGO_CXXFLAGS='-O2 -g' CGO_FFLAGS='-O2 -g' CGO_LDFLAGS='-O2 -g' PKG_CONFIG='pkg-config' GOGCCFLAGS='-fPIC -m64 -pthread -Wl,--no-gc-sections -fmessage-length=0 -ffile-prefix-map=/tmp/go-build1520120181=/tmp/go-build -gno-record-gcc-switches'
What did you do?
$ cd $(go env GOROOT)/src
$ go list ./cmd/missing
stat /home/mvdan/tip/src/cmd/missing: directory not found
$ go generate ./cmd/missing
$ echo $?
0
What did you expect to see?
Both commands should fail on a missing package.
What did you see instead?
go generate appears to happily do nothing.
It could be due to its nature of working with broken packages, for example if the generated files are required for the package to typecheck but they are missing. However, if the package can't be located at all, that should clearly be an error. I had a weird issue at work where I thought my generator wasn't working, simply because I was making a typo when writing go generate ./some/pkg.