cmd/go: upgrade go install pkg@version's go using local mod, work

This CL changes the toolchain selection behavior for go install pkg@v
and go run pkg@v to also take into account the go and toolchain version
lines in the containing go.mod and go.work file.

Before this change, the go command would detect that go install
pkg@version or go run pkg@version was being run and skip the standard
behavior that would select the toolchain based on the go version in the
go.mod or go.work file. It would instead check the go line of the module
being downloaded and switch to that version if necessary.

With this change, the go command does not skip the standard behavior. It
proceeds to determine if an upgrade is required based on the containing
go.mod or go.work file's go and toolchain lines. Then, it checks the
module being installed to see if it would require a higher version than
the determined upgrade (or the local version if no upgrade was
determined). If it does require a higher version, then a switch happens
to that version, and if not the upgrade logic proceeds as usual doing
the upgrade if one was determined.

Fixes #66518

Change-Id: I00d96170e8713c451cc0fd2203be521585418842
Reviewed-on: https://go-review.googlesource.com/c/go/+/660035
Reviewed-by: Junyang Shao <[email protected]>
LUCI-TryBot-Result: Go LUCI <[email protected]>

Author: matloob

src/cmd/go/internal/toolchain/select.go

@@ -169,7 +169,7 @@ func Select() {
 	}
 
 	gotoolchain = minToolchain
-	if (mode == "auto" || mode == "path") && !goInstallVersion(minVers) {
+	if mode == "auto" || mode == "path" {
 		// Read go.mod to find new minimum and suggested toolchain.
 		file, goVers, toolchain := modGoToolchain()
 		gover.Startup.AutoFile = file
@@ -212,6 +212,7 @@ func Select() {
 			}
 			if gover.Compare(goVers, minVers) > 0 {
 				gotoolchain = "go" + goVers
+				minVers = goVers
 				// Starting with Go 1.21, the first released version has a .0 patch version suffix.
 				// Don't try to download a language version (sans patch component), such as go1.22.
 				// Instead, use the first toolchain of that language version, such as 1.22.0.
@@ -230,6 +231,7 @@ func Select() {
 				}
 			}
 		}
+		maybeSwitchForGoInstallVersion(minVers)
 	}
 
 	// If we are invoked as a target toolchain, confirm that
@@ -547,21 +549,21 @@ func modGoToolchain() (file, goVers, toolchain string) {
 	return file, gover.GoModLookup(data, "go"), gover.GoModLookup(data, "toolchain")
 }
 
-// goInstallVersion reports whether the command line is go install m@v or go run m@v.
-// If so, Select must not read the go.mod or go.work file in "auto" or "path" mode.
-func goInstallVersion(minVers string) bool {
+// maybeSwitchForGoInstallVersion reports whether the command line is go install m@v or go run m@v.
+// If so, switch to the go version required to build m@v if it's higher than minVers.
+func maybeSwitchForGoInstallVersion(minVers string) {
 	// Note: We assume there are no flags between 'go' and 'install' or 'run'.
 	// During testing there are some debugging flags that are accepted
 	// in that position, but in production go binaries there are not.
 	if len(os.Args) < 3 {
-		return false
+		return
 	}
 
 	var cmdFlags *flag.FlagSet
 	switch os.Args[1] {
 	default:
 		// Command doesn't support a pkg@version as the main module.
-		return false
+		return
 	case "install":
 		cmdFlags = &work.CmdInstall.Flag
 	case "run":
@@ -595,7 +597,7 @@ func goInstallVersion(minVers string) bool {
 		args = args[1:]
 		if a == "--" {
 			if len(args) == 0 {
-				return false
+				return
 			}
 			pkgArg = args[0]
 			break
@@ -616,7 +618,7 @@ func goInstallVersion(minVers string) bool {
 				val = "true"
 			}
 			if err := modcacherwVal.Set(val); err != nil {
-				return false
+				return
 			}
 			modcacherwSeen = true
 			continue
@@ -636,8 +638,8 @@ func goInstallVersion(minVers string) bool {
 				// because it is preceded by run flags and followed by arguments to the
 				// program being run. Since we don't know whether this flag takes
 				// an argument, we can't reliably identify the end of the run flags.
-				// Just give up and let the user clarify using the "=" form..
-				return false
+				// Just give up and let the user clarify using the "=" form.
+				return
 			}
 
 			// We would like to let 'go install -newflag pkg@version' work even
@@ -666,11 +668,11 @@ func goInstallVersion(minVers string) bool {
 	}
 
 	if !strings.Contains(pkgArg, "@") || build.IsLocalImport(pkgArg) || filepath.IsAbs(pkgArg) {
-		return false
+		return
 	}
 	path, version, _ := strings.Cut(pkgArg, "@")
 	if path == "" || version == "" || gover.IsToolchain(path) {
-		return false
+		return
 	}
 
 	if !modcacherwSeen && base.InGOFLAGS("-modcacherw") {
@@ -679,9 +681,8 @@ func goInstallVersion(minVers string) bool {
 		base.SetFromGOFLAGS(fs)
 	}
 
-	// It would be correct to simply return true here, bypassing use
-	// of the current go.mod or go.work, and let "go run" or "go install"
-	// do the rest, including a toolchain switch.
+	// It would be correct to do nothing here, and let "go run" or "go install"
+	// do the toolchain switch.
 	// Our goal instead is, since we have gone to the trouble of handling
 	// unknown flags to some degree, to run the switch now, so that
 	// these commands can switch to a newer toolchain directed by the
@@ -714,6 +715,4 @@ func goInstallVersion(minVers string) bool {
 			SwitchOrFatal(ctx, err)
 		}
 	}
-
-	return true // pkg@version found
 }

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

@@ -197,6 +197,8 @@ go mod edit -go=1.501 -toolchain=none
 go version
 stdout go1.501
 
+go mod edit -go=1.21
+
 # avoid two-step switch, first from install target requirement, then from GOTOOLCHAIN min
 # instead, just jump directly to GOTOOLCHAIN min
 env TESTGO_VERSION=go1.2.3
@@ -205,21 +207,49 @@ env GOTOOLCHAIN=go1.23.0+auto
 ! go install rsc.io/fortune/[email protected]
 ! stderr 'switching to go1.22.9'
 stderr 'using go1.23.0'
-env GODEBUG=
 env GOTOOLCHAIN=auto
 
-# go install m@v and go run m@v should ignore go.mod and use m@v
+# go install m@v and go run m@v should use the go directive from m@v,
+# or the go directive in go.mod, whichever is higher.
 env TESTGO_VERSION=go1.2.3
-go mod edit -go=1.999 -toolchain=go1.998
+go mod edit -go=1.1.1 -toolchain=go1.1.1
 
 ! go install rsc.io/fortune/[email protected]
 stderr '^go: rsc.io/[email protected] requires go >= 1.21rc999; switching to go1.22.9$'
+! stderr 'upgrading toolchain'
 stderr '^go: rsc.io/fortune/[email protected]: module rsc.io/[email protected] found, but does not contain package rsc.io/fortune/nonexist'
 
 ! go run rsc.io/fortune/[email protected]
 stderr '^go: rsc.io/[email protected] requires go >= 1.21rc999; switching to go1.22.9$'
+! stderr 'upgrading toolchain'
+stderr '^go: rsc.io/fortune/[email protected]: module rsc.io/[email protected] found, but does not contain package rsc.io/fortune/nonexist'
+
+go mod edit -go=1.23rc1 -toolchain=go1.1.1
+
+! go install rsc.io/fortune/[email protected]
+stderr '^go: upgrading toolchain to go1.23rc1 \(required by go line in go.mod; upgrade allowed by GOTOOLCHAIN=auto\)'
+! stderr 'switching to'
 stderr '^go: rsc.io/fortune/[email protected]: module rsc.io/[email protected] found, but does not contain package rsc.io/fortune/nonexist'
 
+! go run rsc.io/fortune/[email protected]
+stderr '^go: upgrading toolchain to go1.23rc1 \(required by go line in go.mod; upgrade allowed by GOTOOLCHAIN=auto\)'
+! stderr 'switching to'
+stderr '^go: rsc.io/fortune/[email protected]: module rsc.io/[email protected] found, but does not contain package rsc.io/fortune/nonexist'
+
+go mod edit -go=1.23rc1 -toolchain=go1.998
+
+! go install rsc.io/fortune/[email protected]
+stderr '^go: upgrading toolchain to go1.998 \(required by toolchain line in go.mod; upgrade allowed by GOTOOLCHAIN=auto\)'
+! stderr 'switching to'
+stderr '^go: rsc.io/fortune/[email protected]: module rsc.io/[email protected] found, but does not contain package rsc.io/fortune/nonexist'
+
+! go run rsc.io/fortune/[email protected]
+stderr '^go: upgrading toolchain to go1.998 \(required by toolchain line in go.mod; upgrade allowed by GOTOOLCHAIN=auto\)'
+! stderr 'switching to'
+stderr '^go: rsc.io/fortune/[email protected]: module rsc.io/[email protected] found, but does not contain package rsc.io/fortune/nonexist'
+
+go mod edit -go=1.1.1 -toolchain=go1.1.1
+
 # go install should handle unknown flags to find m@v
 ! go install -unknownflag rsc.io/fortune/[email protected]
 stderr '^go: rsc.io/[email protected] requires go >= 1.21rc999; switching to go1.22.9$'
@@ -229,6 +259,8 @@ stderr '^flag provided but not defined: -unknownflag'
 stderr '^go: rsc.io/[email protected] requires go >= 1.21rc999; switching to go1.22.9$'
 stderr '^flag provided but not defined: -unknownflag'
 
+env GODEBUG=
+
 # go run cannot handle unknown boolean flags
 ! go run -unknownflag rsc.io/fortune/[email protected]
 ! stderr switching

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

@@ -59,8 +59,8 @@ stderr 'running go1.50.0 from PATH'
 
 # NewerToolchain should find Go 1.50.0.
 env GOTOOLCHAIN=local
-go mod edit -toolchain=none -go=1.22
-grep 'go 1.22$' go.mod
+go mod edit -toolchain=none -go=1.21
+grep 'go 1.21$' go.mod
 ! grep toolchain go.mod
 env GOTOOLCHAIN=path
 ! go run rsc.io/[email protected]