cmd/go/internal/test: stale flagdefs.go not detected by tests

[empire]

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

$ go version # installed Go
go version go1.19.5 darwin/arm64

$ go version # built Go
go version devel go1.21-1a09d57de5 Wed Feb 8 14:52:12 2023 +0000 darwin/arm64

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="on"
GOARCH="arm64"
GOBIN=""
GOCACHE="/Users/hossein/Library/Caches/go-build"
GOENV="/Users/hossein/Library/Application Support/go/env"
GOEXE=""
GOEXPERIMENT=""
GOFLAGS=""
GOHOSTARCH="arm64"
GOHOSTOS="darwin"
GOINSECURE=""
GOMODCACHE="/Users/hossein/.local/share/go/pkg/mod"
GONOPROXY=""
GONOSUMDB="gitlab.snapp.ir"
GOOS="darwin"
GOPATH="/Users/hossein/.local/share/go"
GOPRIVATE=""
GOPROXY="https://repo.snapp.tech/repository/goproxy/,goproxy.cn,goproxy.io,direct"
GOROOT="/opt/homebrew/Cellar/go/1.19.5/libexec"
GOSUMDB="sum.golang.org"
GOTMPDIR=""
GOTOOLDIR="/opt/homebrew/Cellar/go/1.19.5/libexec/pkg/tool/darwin_arm64"
GOVCS=""
GOVERSION="go1.19.5"
GCCGO="gccgo"
AR="ar"
CC="clang"
CXX="clang++"
CGO_ENABLED="1"
GOMOD="/Users/hossein/Projects/github.com/golang/go/src/cmd/go.mod"
GOWORK=""
CGO_CFLAGS="-g -O2"
CGO_CPPFLAGS=""
CGO_CXXFLAGS="-g -O2"
CGO_FFLAGS="-g -O2"
CGO_LDFLAGS="-g -O2"
PKG_CONFIG="pkg-config"
GOGCCFLAGS="-fPIC -arch arm64 -pthread -fno-caret-diagnostics -Qunused-arguments -fmessage-length=0 -fdebug-prefix-map=/var/folders/28/0tv7m8993k3859p1zrmyr0th0000gn/T/go-build4070024279=/tmp/go-build -gno-record-gcc-switches -fno-common"

What did you do?

In order to implement #37708, I ran the following command to generate the needed files, but the command also changed unrelated lines. This behavior is strange, so I filled this issue based on @ianlancetaylor 's feedback.

The output remains the same when using the built version of Go.

cd src/cmd/go/internal/test
go generate ./...

git diff Output

$ git diff
diff --git a/src/cmd/go/internal/test/flagdefs.go b/src/cmd/go/internal/test/flagdefs.go
index 1e0772fe9c..93681498cb 100644
--- a/src/cmd/go/internal/test/flagdefs.go
+++ b/src/cmd/go/internal/test/flagdefs.go
@@ -23,6 +23,7 @@ var passFlagToTest = map[string]bool{
 	"fuzz":                 true,
 	"fuzzminimizetime":     true,
 	"fuzztime":             true,
+	"gocoverdir":           true,
 	"list":                 true,
 	"memprofile":           true,
 	"memprofilerate":       true,
@@ -50,6 +51,7 @@ var passAnalyzersToVet = map[string]bool{
 	"cgocall":          true,
 	"composites":       true,
 	"copylocks":        true,
+	"directive":        true,
 	"errorsas":         true,
 	"framepointer":     true,
 	"httpresponse":     true,
@@ -67,6 +69,7 @@ var passAnalyzersToVet = map[string]bool{
 	"structtag":        true,
 	"testinggoroutine": true,
 	"tests":            true,
+	"timeformat":       true,
 	"unmarshal":        true,
 	"unreachable":      true,
 	"unsafeptr":        true,

I ran the following command to generate the alldocs.go content. When using the built Go command, everything seems fine, but when using the installed Go command, non-related lines are also changed.

cd src/cmd/go
./mkalldocs.sh

git diff Output

$ git diff
diff --git a/src/cmd/go/alldocs.go b/src/cmd/go/alldocs.go
index 84afcab7a0..a3c1fecb91 100644
--- a/src/cmd/go/alldocs.go
+++ b/src/cmd/go/alldocs.go
@@ -97,13 +97,12 @@
 // ends with a slash or backslash, then any resulting executables
 // will be written to that directory.
 //
+// The -i flag installs the packages that are dependencies of the target.
+// The -i flag is deprecated. Compiled packages are cached automatically.
+//
 // The build flags are shared by the build, clean, get, install, list, run,
 // and test commands:
 //
-//	-C dir
-//		Change to dir before running the command.
-//		Any files named on the command line are interpreted after
-//		changing directories.
 //	-a
 //		force rebuilding of packages that are already up-to-date.
 ... (more output is truncated)

What did you expect to see?

No diff when running the git diff command and the extra lines do not need to be modified.

What did you see instead?

Lines not related to the CL are modified.

[bcmills]

It looks like some changes in the standard library needed to update flagdefs.go but didn't.

We have tests that are supposed to catch that, but for some reason they didn't.

[bcmills]

@gopherbot, please backport to Go 1.20. This masked two missing vet analyzer flags that should be added.

[gopherbot]

Change https://go.dev/cl/466635 mentions this issue: cmd/go/internal/test: refresh flagdefs.go and fix test

[gopherbot]

Backport issue(s) opened: #58421 (for 1.20).

Remember to create the cherry-pick CL(s) as soon as the patch is submitted to master, according to https://go.dev/wiki/MinorReleases.

[gopherbot]

Change https://go.dev/cl/466695 mentions this issue: cmd/go: rewrite generate tests using the new maps package

[gopherbot]

Change https://go.dev/cl/466855 mentions this issue: [release-branch.go1.20] cmd/go/internal/test: refresh flagdefs.go and fix test