proposal: go/parser: deprecate parser.ParseDir (which returns deprecated type ast.Package)

[soerenkoehler]

Go version

1.23.4

Output of go env in your module/workspace:

GO111MODULE=''
GOARCH='amd64'
GOBIN=''
GOCACHE='/home/soeren/.cache/go-build'
GOENV='/home/soeren/.config/go/env'
GOEXE=''
GOEXPERIMENT='nocoverageredesign'
GOFLAGS=''
GOHOSTARCH='amd64'
GOHOSTOS='linux'
GOINSECURE=''
GOMODCACHE='/home/soeren/go/pkg/mod'
GONOPROXY=''
GONOSUMDB=''
GOOS='linux'
GOPATH='/home/soeren/go'
GOPRIVATE=''
GOPROXY='direct'
GOROOT='/opt/go'
GOSUMDB='sum.golang.org'
GOTMPDIR=''
GOTOOLCHAIN='auto'
GOTOOLDIR='/opt/go/pkg/tool/linux_amd64'
GOVCS=''
GOVERSION='go1.23.4'
GODEBUG=''
GOTELEMETRY='local'
GOTELEMETRYDIR='/home/soeren/.config/go/telemetry'
GCCGO='gccgo'
GOAMD64='v1'
AR='ar'
CC='gcc'
CXX='g++'
CGO_ENABLED='1'
GOMOD='/home/soeren/usrdev/go-util-mutation/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-build2925151345=/tmp/go-build -gno-record-gcc-switches'

What did you do?

Write some simple code using the go/ast and go/parser:

func createAST() {
	ast := map[string]*ast.Package{}
	fset := token.NewFileSet()
	chain := &util.ChainContext{}

	chain.Chain(func() {
		ast, chain.Err = parser.ParseDir(fset, ".", nil, 0)
	}).Chain(func() {
		chain.Err = format.Node(os.Stdout, fset, ast)
	}).ChainFatal("Error")
}

What did you see happen?

The IDE marks ast.Package as deprecated conforming to the comment on the type. But parser.ParseDir() nevertheless references ast.Package in its return type.

What did you expect to see?

Either:

• Having deprecated types consistently replaced in the stdlib. Thus, let ParseDir() use the recommended replacement type.

Or:

• Having ParseDir() marked as deprecated too.

[gabyhelp]

Related Issues

• x/tools/go/ast/astutil : Unparen bad use of go/ast Unparen #69361 (closed)
• go/ast: formally deprecate Object #52463 (closed)

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

[adonovan]

What did you expect to see?
Either: Having deprecated types consistently replaced in the stdlib. Thus, let ParseDir() use the recommended replacement type.

ParseDir cannot be compatibly changed to return the recommended replacement type.

Or: Having ParseDir() marked as deprecated to.

I think parser.ParseDir is almost never the best solution to a problem, and it returns deprecated data structures, so it does make sense to deprecate it. A more robust solution is to use packages.Load, which invokes go list (or the appropriate build metadata query tool) to get the correct answer.