cmd/go: set go.work path using GOWORK, and remove -workfile flag

This change removes the -workfile flag and allows the go.work file path
to be set using GOWORK (which was previously read-only). This removes
the potential discrepancy and confusion between the flag and environment
variable.

GOWORK will still return the actual path of the go.work file found if it
is set to '' or 'auto'. GOWORK will return 'off' if it is set to 'off'.

For #45713
Fixes #51171

Change-Id: I72eed65d47c63c81433f2b54158d514daeaa1ab3
Reviewed-on: https://go-review.googlesource.com/c/go/+/385995
Trust: Michael Matloob <[email protected]>
Run-TryBot: Michael Matloob <[email protected]>
TryBot-Result: Gopher Robot <[email protected]>
Reviewed-by: Bryan Mills <[email protected]>

doc/go1.18.html

@@ -345,8 +345,8 @@ <h3 id="go-command">Go command</h3>
 <p><!-- https://golang.org/issue/45713 -->
   The <code>go</code> command now supports a "Workspace" mode. If a
   <code>go.work</code> file is found in the working directory or a
-  parent directory, or one is specified using the <code>-workfile</code>
-  flag, it will put the <code>go</code> command into workspace mode.
+  parent directory, or one is specified using the <code>GOWORK</code>
+  environment variable, it will put the <code>go</code> command into workspace mode.
   In workspace mode, the <code>go.work</code> file will be used to
   determine the set of main modules used as the roots for module
   resolution, instead of using the normally-found <code>go.mod</code>

src/cmd/go/internal/base/flag.go

@@ -62,13 +62,6 @@ func AddModFlag(flags *flag.FlagSet) {
 	flags.Var(explicitStringFlag{value: &cfg.BuildMod, explicit: &cfg.BuildModExplicit}, "mod", "")
 }
 
-// AddWorkfileFlag adds the workfile flag to the flag set. It enables workspace
-// mode for commands that support it by resetting the cfg.WorkFile variable
-// to "" (equivalent to auto) rather than off.
-func AddWorkfileFlag(flags *flag.FlagSet) {
-	flags.Var(explicitStringFlag{value: &cfg.WorkFile, explicit: &cfg.WorkFileExplicit}, "workfile", "")
-}
-
 // AddModCommonFlags adds the module-related flags common to build commands
 // and 'go mod' subcommands.
 func AddModCommonFlags(flags *flag.FlagSet) {

src/cmd/go/internal/cfg/cfg.go

@@ -49,10 +49,8 @@ var (
 	BuildWork              bool // -work flag
 	BuildX                 bool // -x flag
 
-	ModCacheRW       bool   // -modcacherw flag
-	ModFile          string // -modfile flag
-	WorkFile         string // -workfile flag
-	WorkFileExplicit bool   // whether -workfile was set explicitly
+	ModCacheRW bool   // -modcacherw flag
+	ModFile    string // -modfile flag
 
 	CmdName string // "build", "install", "list", "mod tidy", etc.
 

src/cmd/go/internal/envcmd/env.go

@@ -154,6 +154,10 @@ func ExtraEnvVars() []cfg.EnvVar {
 	}
 	modload.InitWorkfile()
 	gowork := modload.WorkFilePath()
+	// As a special case, if a user set off explicitly, report that in GOWORK.
+	if cfg.Getenv("GOWORK") == "off" {
+		gowork = "off"
+	}
 	return []cfg.EnvVar{
 		{Name: "GOMOD", Value: gomod},
 		{Name: "GOWORK", Value: gowork},

src/cmd/go/internal/help/helpdoc.go

@@ -545,6 +545,14 @@ General-purpose environment variables:
 	GOVCS
 		Lists version control commands that may be used with matching servers.
 		See 'go help vcs'.
+	GOWORK
+		In module aware mode, use the given go.work file as a workspace file.
+		By default or when GOWORK is "auto", the go command searches for a
+		file named go.work in the current directory and then containing directories
+		until one is found. If a valid go.work file is found, the modules
+		specified will collectively be used as the main modules. If GOWORK
+		is "off", or a go.work file is not found in "auto" mode, workspace
+		mode is disabled.
 
 Environment variables for use with cgo:
 

src/cmd/go/internal/list/list.go

@@ -316,7 +316,6 @@ For more about modules, see https://golang.org/ref/mod.
 func init() {
 	CmdList.Run = runList // break init cycle
 	work.AddBuildFlags(CmdList, work.DefaultBuildFlags)
-	base.AddWorkfileFlag(&CmdList.Flag)
 }
 
 var (

src/cmd/go/internal/modcmd/download.go

@@ -70,7 +70,6 @@ func init() {
 	// TODO(jayconrod): https://golang.org/issue/35849 Apply -x to other 'go mod' commands.
 	cmdDownload.Flag.BoolVar(&cfg.BuildX, "x", false, "")
 	base.AddModCommonFlags(&cmdDownload.Flag)
-	base.AddWorkfileFlag(&cmdDownload.Flag)
 }
 
 type moduleJSON struct {

src/cmd/go/internal/modcmd/graph.go

@@ -42,7 +42,6 @@ var (
 func init() {
 	cmdGraph.Flag.Var(&graphGo, "go", "")
 	base.AddModCommonFlags(&cmdGraph.Flag)
-	base.AddWorkfileFlag(&cmdGraph.Flag)
 }
 
 func runGraph(ctx context.Context, cmd *base.Command, args []string) {

src/cmd/go/internal/modcmd/verify.go

@@ -39,7 +39,6 @@ See https://golang.org/ref/mod#go-mod-verify for more about 'go mod verify'.
 
 func init() {
 	base.AddModCommonFlags(&cmdVerify.Flag)
-	base.AddWorkfileFlag(&cmdVerify.Flag)
 }
 
 func runVerify(ctx context.Context, cmd *base.Command, args []string) {

src/cmd/go/internal/modcmd/why.go

@@ -59,7 +59,6 @@ var (
 func init() {
 	cmdWhy.Run = runWhy // break init cycle
 	base.AddModCommonFlags(&cmdWhy.Flag)
-	base.AddWorkfileFlag(&cmdWhy.Flag)
 }
 
 func runWhy(ctx context.Context, cmd *base.Command, args []string) {

src/cmd/go/internal/modload/init.go

@@ -288,16 +288,16 @@ func BinDir() string {
 // operate in workspace mode. It should not be called by other commands,
 // for example 'go mod tidy', that don't operate in workspace mode.
 func InitWorkfile() {
-	switch cfg.WorkFile {
+	switch gowork := cfg.Getenv("GOWORK"); gowork {
 	case "off":
 		workFilePath = ""
 	case "", "auto":
 		workFilePath = findWorkspaceFile(base.Cwd())
 	default:
-		if !filepath.IsAbs(cfg.WorkFile) {
-			base.Fatalf("the path provided to -workfile must be an absolute path")
+		if !filepath.IsAbs(gowork) {
+			base.Fatalf("the path provided to GOWORK must be an absolute path")
 		}
-		workFilePath = cfg.WorkFile
+		workFilePath = gowork
 	}
 }
 
@@ -1109,7 +1109,7 @@ func setDefaultBuildMod() {
 		if inWorkspaceMode() && cfg.BuildMod != "readonly" {
 			base.Fatalf("go: -mod may only be set to readonly when in workspace mode, but it is set to %q"+
 				"\n\tRemove the -mod flag to use the default readonly value,"+
-				"\n\tor set -workfile=off to disable workspace mode.", cfg.BuildMod)
+				"\n\tor set GOWORK=off to disable workspace mode.", cfg.BuildMod)
 		}
 		// Don't override an explicit '-mod=' argument.
 		return

src/cmd/go/internal/run/run.go

@@ -65,7 +65,6 @@ func init() {
 	CmdRun.Run = runRun // break init loop
 
 	work.AddBuildFlags(CmdRun, work.DefaultBuildFlags)
-	base.AddWorkfileFlag(&CmdRun.Flag)
 	CmdRun.Flag.Var((*base.StringsFlag)(&work.ExecCmd), "exec", "")
 }
 

src/cmd/go/internal/test/testflag.go

@@ -28,7 +28,6 @@ import (
 
 func init() {
 	work.AddBuildFlags(CmdTest, work.OmitVFlag)
-	base.AddWorkfileFlag(&CmdTest.Flag)
 
 	cf := CmdTest.Flag
 	cf.BoolVar(&testC, "c", false, "")

src/cmd/go/internal/work/build.go

@@ -130,14 +130,6 @@ and test commands:
 		directory, but it is not accessed. When -modfile is specified, an
 		alternate go.sum file is also used: its path is derived from the
 		-modfile flag by trimming the ".mod" extension and appending ".sum".
-	-workfile file
-		in module aware mode, use the given go.work file as a workspace file.
-		By default or when -workfile is "auto", the go command searches for a
-		file named go.work in the current directory and then containing directories
-		until one is found. If a valid go.work file is found, the modules
-		specified will collectively be used as the main modules. If -workfile
-		is "off", or a go.work file is not found in "auto" mode, workspace
-		mode is disabled.
 	-overlay file
 		read a JSON config file that provides an overlay for build operations.
 		The file is a JSON struct with a single field, named 'Replace', that
@@ -217,7 +209,6 @@ func init() {
 
 	AddBuildFlags(CmdBuild, DefaultBuildFlags)
 	AddBuildFlags(CmdInstall, DefaultBuildFlags)
-	base.AddWorkfileFlag(&CmdBuild.Flag)
 }
 
 // Note that flags consulted by other parts of the code

src/cmd/go/internal/workcmd/edit.go

@@ -110,8 +110,6 @@ func init() {
 	cmdEdit.Flag.Var(flagFunc(flagEditworkDropUse), "dropuse", "")
 	cmdEdit.Flag.Var(flagFunc(flagEditworkReplace), "replace", "")
 	cmdEdit.Flag.Var(flagFunc(flagEditworkDropReplace), "dropreplace", "")
-
-	base.AddWorkfileFlag(&cmdEdit.Flag)
 }
 
 func runEditwork(ctx context.Context, cmd *base.Command, args []string) {
@@ -137,7 +135,7 @@ func runEditwork(ctx context.Context, cmd *base.Command, args []string) {
 	}
 
 	if gowork == "" {
-		base.Fatalf("go: no go.work file found\n\t(run 'go work init' first or specify path using -workfile flag)")
+		base.Fatalf("go: no go.work file found\n\t(run 'go work init' first or specify path using GOWORK environment variable)")
 	}
 
 	anyFlags :=

src/cmd/go/internal/workcmd/init.go

@@ -33,19 +33,13 @@ current go version will also be listed in the go.work file.
 
 func init() {
 	base.AddModCommonFlags(&cmdInit.Flag)
-	base.AddWorkfileFlag(&cmdInit.Flag)
 }
 
 func runInit(ctx context.Context, cmd *base.Command, args []string) {
 	modload.InitWorkfile()
 
 	modload.ForceUseModules = true
 
-	// TODO(matloob): support using the -workfile path
-	// To do that properly, we'll have to make the module directories
-	// make dirs relative to workFile path before adding the paths to
-	// the directory entries
-
 	workFile := modload.WorkFilePath()
 	if workFile == "" {
 		workFile = filepath.Join(base.Cwd(), "go.work")

src/cmd/go/internal/workcmd/sync.go

@@ -39,14 +39,13 @@ that in each workspace module.
 
 func init() {
 	base.AddModCommonFlags(&cmdSync.Flag)
-	base.AddWorkfileFlag(&cmdSync.Flag)
 }
 
 func runSync(ctx context.Context, cmd *base.Command, args []string) {
 	modload.ForceUseModules = true
 	modload.InitWorkfile()
 	if modload.WorkFilePath() == "" {
-		base.Fatalf("go: no go.work file found\n\t(run 'go work init' first or specify path using -workfile flag)")
+		base.Fatalf("go: no go.work file found\n\t(run 'go work init' first or specify path using GOWORK environment variable)")
 	}
 
 	workGraph := modload.LoadModGraph(ctx, "")

src/cmd/go/internal/workcmd/use.go

@@ -42,7 +42,6 @@ func init() {
 	cmdUse.Run = runUse // break init cycle
 
 	base.AddModCommonFlags(&cmdUse.Flag)
-	base.AddWorkfileFlag(&cmdUse.Flag)
 }
 
 func runUse(ctx context.Context, cmd *base.Command, args []string) {
@@ -53,7 +52,7 @@ func runUse(ctx context.Context, cmd *base.Command, args []string) {
 	gowork = modload.WorkFilePath()
 
 	if gowork == "" {
-		base.Fatalf("go: no go.work file found\n\t(run 'go work init' first or specify path using -workfile flag)")
+		base.Fatalf("go: no go.work file found\n\t(run 'go work init' first or specify path using GOWORK environment variable)")
 	}
 	workFile, err := modload.ReadWorkFile(gowork)
 	if err != nil {

src/cmd/go/testdata/script/work.txt

@@ -32,7 +32,9 @@ stdout 'example.com/b'
 go list -mod=readonly all
 ! go list -mod=mod all
 stderr '^go: -mod may only be set to readonly when in workspace mode'
-go list -mod=mod -workfile=off all
+env GOWORK=off
+go list -mod=mod all
+env GOWORK=
 
 # Test that duplicates in the use list return an error
 cp go.work go.work.backup
@@ -53,7 +55,9 @@ go run example.com/d
 # This exercises the code that determines which module command-line-arguments
 # belongs to.
 go list ./b/main.go
-go build -n -workfile=off -o foo foo.go
+env GOWORK=off
+go build -n -o foo foo.go
+env GOWORK=
 go build -n -o foo foo.go
 
 -- go.work.dup --

src/cmd/go/testdata/script/work_edit.txt

@@ -30,7 +30,8 @@ cmp stdout go.work.want_print
 go work edit -json -go 1.19 -use b -dropuse c -replace '[email protected] = ../z' -dropreplace x.1 -dropreplace [email protected]
 cmp stdout go.work.want_json
 
-go work edit -print -fmt -workfile $GOPATH/src/unformatted
+env GOWORK=$GOPATH/src/unformatted
+go work edit -print -fmt
 cmp stdout formatted
 
 -- m/go.mod --

src/cmd/go/testdata/script/work_env.txt

@@ -13,6 +13,10 @@ cd src
 go env GOWORK
 stdout 'go.work'
 
+env GOWORK='off'
+go env GOWORK
+stdout 'off'
+
 ! go env -w GOWORK=off
 stderr '^go: GOWORK cannot be modified$'
 

src/cmd/go/testdata/script/work_gowork.txt

@@ -0,0 +1,24 @@
+env GOWORK=stop.work
+! go list a # require absolute path
+! stderr panic
+env GOWORK=doesnotexist
+! go list a
+! stderr panic
+
+env GOWORK=$GOPATH/src/stop.work
+go list -n a
+go build -n a
+go test -n a
+
+-- stop.work --
+go 1.18
+
+use ./a
+-- a/a.go --
+package a
+-- a/a_test.go --
+package a
+-- a/go.mod --
+module a
+
+go 1.18

src/cmd/go/testdata/script/work_init_workfile.txt → src/cmd/go/testdata/script/work_init_gowork.txt

@@ -1,11 +1,15 @@
-# Test that the workfile flag is used by go work init.
+# Test that the GOWORK environment variable flag is used by go work init.
 
+! exists go.work
 go work init
 exists go.work
 
-go work init -workfile=$GOPATH/src/foo/foo.work
+env GOWORK=$GOPATH/src/foo/foo.work
+! exists foo/foo.work
+go work init
 exists foo/foo.work
 
+env GOWORK=
 cd foo/bar
 ! go work init
 stderr 'already exists'

src/cmd/go/testdata/script/work_nowork.txt

@@ -1,17 +1,17 @@
 ! go work use
-stderr '^go: no go\.work file found\n\t\(run ''go work init'' first or specify path using -workfile flag\)$'
+stderr '^go: no go\.work file found\n\t\(run ''go work init'' first or specify path using GOWORK environment variable\)$'
 
 ! go work use .
-stderr '^go: no go\.work file found\n\t\(run ''go work init'' first or specify path using -workfile flag\)$'
+stderr '^go: no go\.work file found\n\t\(run ''go work init'' first or specify path using GOWORK environment variable\)$'
 
 ! go work edit
-stderr '^go: no go\.work file found\n\t\(run ''go work init'' first or specify path using -workfile flag\)$'
+stderr '^go: no go\.work file found\n\t\(run ''go work init'' first or specify path using GOWORK environment variable\)$'
 
 ! go work edit -go=1.18
-stderr '^go: no go\.work file found\n\t\(run ''go work init'' first or specify path using -workfile flag\)$'
+stderr '^go: no go\.work file found\n\t\(run ''go work init'' first or specify path using GOWORK environment variable\)$'
 
 ! go work sync
-stderr '^go: no go\.work file found\n\t\(run ''go work init'' first or specify path using -workfile flag\)$'
+stderr '^go: no go\.work file found\n\t\(run ''go work init'' first or specify path using GOWORK environment variable\)$'
 
 -- go.mod --
 module example