cmd/go: -cover flag documentation out of date

[enrichman]

While playing with the new -cover flag I was trying to see how to switch to the covermod=count.

Running the go help build I've seen no available flag for it, but still the -covermod flag is available and working fine.

I've seen also that the -cover flag is showing a probably old message (the GOEXPERIMENT env var is not required).

-cover
	enable code coverage instrumentation (requires
	that GOEXPERIMENT=coverageredesign be set).

I'm willing to help about this if is confirmed as an issue, or just a doc misalignment.

The docs says that it's generated with a mkalldocs.sh script, but I haven't found it.

What version of Go are you using (go version)?

$ go version
go version go1.20.4 darwin/amd64

Does this issue reproduce with the latest release?

Yes.

What operating system and processor architecture are you using (go env)?

go env Output

$ go env
GO111MODULE=""
GOARCH="amd64"
GOBIN="/Users/enrico/Development/go/bin"
GOCACHE="/Users/enrico/Library/Caches/go-build"
GOENV="/Users/enrico/Library/Application Support/go/env"
GOEXE=""
GOEXPERIMENT=""
GOFLAGS=""
GOHOSTARCH="amd64"
GOHOSTOS="darwin"
GOINSECURE=""
GOMODCACHE="/Users/enrico/Development/go/pkg/mod"
GONOPROXY=""
GONOSUMDB=""
GOOS="darwin"
GOPATH="/Users/enrico/Development/go"
GOPRIVATE=""
GOPROXY="https://proxy.golang.org,direct"
GOROOT="/usr/local/go"
GOSUMDB="sum.golang.org"
GOTMPDIR=""
GOTOOLDIR="/usr/local/go/pkg/tool/darwin_amd64"
GOVCS=""
GOVERSION="go1.20.4"
GCCGO="gccgo"
GOAMD64="v1"
AR="ar"
CC="clang"
CXX="clang++"
CGO_ENABLED="1"
GOMOD="/dev/null"
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 -arch x86_64 -m64 -pthread -fno-caret-diagnostics -Qunused-arguments -fmessage-length=0 -fdebug-prefix-map=/var/folders/dg/xjrxmyds5p7_7xm9r12m79xw0000gn/T/go-build3135499840=/tmp/go-build -gno-record-gcc-switches -fno-common"

What did you do?

Run a go help build.

What did you expect to see?

The "right" -cover flag message, and the missing -covermod flag message.

[enrichman]

Thanks @seankhliao for the title, I hit return too early. 😄

[seankhliao]

feel free to submit a PR/CL
if you run go test with the version you edited, it should output instructions on keeping everything up to date

[ianlancetaylor]

CC @thanm

[enrichman]

I'm not sure if this could be the chance to drop the goexperiment.CoverageRedesign flag.
Maybe in a separate PR, keeping this one only for the doc?

[gopherbot]

Change https://go.dev/cl/498415 mentions this issue: cmd/go: update cover flag documentation