extension: update go to go1.23.1

We want to use the latest go when developing our own
release/testing support tools and scripts.
So, let's update go.mod to do so.

After go1.21, we shouldn't use `go run` to run
the extension/tools/installtools script.
The purpose of `installtools` is to install tools
needed by integration tests and are compatible with
the go version in the system. We arranged the CI
systems to test with the go versions we support.
If we use `go run` from our project, the toolchain
switch will occur and may change `GOROOT`/`PATH`
to enforce the compiled script to use the upgraded
toolchain. That makes the CI setup useless.

Therefore, in this CL, we build the binary (it's ok to
build the binary with go1.23.1+), and then run
the installed binary ourselves so the execution of
the binary doesn't get affected by the modified
GOROOT/PATH.

Kokoro CI also uses the installtools script when
building the docker container. (build/Dockerfile)
There, the script source code is copied over to a
scratch space and run with `go run <go file>`
outside the vscode-go project repo. So, there is
no go toolchain version switch involved already.

And currently we test only with the latest go in
Kokoro, so this toolchain switch issue doesn't apply.

For #3411

Change-Id: I3e116cf48fb431196359ec42049e70c0b75814ef
Reviewed-on: https://go-review.googlesource.com/c/vscode-go/+/616677
kokoro-CI: kokoro <[email protected]>
Reviewed-by: Hongxiang Jiang <[email protected]>
Commit-Queue: Hyang-Ah Hana Kim <[email protected]>

Author: hyangah

Diff for: .github/workflows/test-long-all.yml

@@ -37,22 +37,19 @@ jobs:
          check-latest: true
          cache: true
 
-      - name: Install dependencies
+      - name: Install NPM dependencies
         run: npm ci
         working-directory: ./extension
 
       - name: Compile
         run: npm run vscode:prepublish
         working-directory: ./extension
 
-      - name: Install Go tools (Modules mode)
+      - name: Install tools dependencies
         run: |
-            go version
-            go run ./tools/installtools/main.go
+          go install ./tools/installtools
+          installtools
         working-directory: ./extension
-        env:
-          GO111MODULE: on
-          EXT: "${{ matrix.os == 'windows-latest' && '.exe' || ''}}"
 
       - name: Run unit tests
         run: npm run unit-test

Diff for: .github/workflows/test-long.yml

@@ -36,22 +36,19 @@ jobs:
          check-latest: true
          cache: true
 
-      - name: Install dependencies
+      - name: Install NPM dependencies
         run: npm ci
         working-directory: ./extension
 
       - name: Compile
         run: npm run vscode:prepublish
         working-directory: ./extension
 
-      - name: Install Go tools (Modules mode)
+      - name: Install tools dependencies
         run: |
-            go version
-            go run ./tools/installtools/main.go
+          go install ./tools/installtools
+          installtools
         working-directory: ./extension
-        env:
-          GO111MODULE: on
-          EXT: "${{ matrix.os == 'windows-latest' && '.exe' || ''}}"
 
       - name: Run unit tests
         run: npm run unit-test

Diff for: .github/workflows/test-smoke.yml

@@ -43,14 +43,11 @@ jobs:
         run: npm run vscode:prepublish
         working-directory: ./extension
 
-      - name: Install Go tools (Modules mode)
+      - name: Install tools dependencies
         run: |
-            go version
-            go run ./tools/installtools/main.go
+          go install ./tools/installtools
+          installtools
         working-directory: ./extension
-        env:
-          GO111MODULE: on
-          EXT: "${{ matrix.os == 'windows-latest' && '.exe' || ''}}"
 
       - name: Run unit tests
         run: npm run unit-test

Diff for: extension/go.mod

@@ -1,8 +1,6 @@
 module github.com/golang/vscode-go/extension
 
-go 1.21
-
-toolchain go1.21.9
+go 1.23.1
 
 require (
 	github.com/golang/vscode-go v0.0.0-00010101000000-000000000000

Diff for: extension/tools/installtools/main.go

@@ -3,6 +3,13 @@
 // license that can be found in the LICENSE file.
 
 // Binary installtools is a helper that installs Go tools extension tests depend on.
+// In order to allow this script to use the go version in the sytem or your choice,
+// avoid running this with `go run` (that may auto-upgrade the toolchain to meet
+// the go version requirement in extension/go.mod).
+// Instead, build this script, and run the compiled executable.
+// For example,
+//
+//	go build -o /tmp/script . && /tmp/script
 package main
 
 import (
@@ -61,6 +68,7 @@ func main() {
 	if ver < 21 {
 		exitf("unsupported go version: 1.%v", ver)
 	}
+	fmt.Printf("installing tools for go1.%d...\n", ver)
 
 	bin, err := goBin()
 	if err != nil {
@@ -80,7 +88,9 @@ func exitf(format string, args ...interface{}) {
 // goVersion returns an integer N if go's version is 1.N.
 func goVersion() (int, error) {
 	cmd := exec.Command("go", "list", "-e", "-f", `{{context.ReleaseTags}}`, "--", "unsafe")
-	cmd.Env = append(os.Environ(), "GO111MODULE=off")
+	// GO111MODULE=off implicitly disables GOTOOLCHAIN switch,
+	// but let's make sure it doesn't change.
+	cmd.Env = append(os.Environ(), "GO111MODULE=off", "GOTOOLCHAIN=local")
 	out, err := cmd.Output()
 	if err != nil {
 		return 0, fmt.Errorf("go list error: %v", err)
@@ -106,7 +116,8 @@ func goBin() (string, error) {
 	if gobin := os.Getenv("GOBIN"); gobin != "" {
 		return gobin, nil
 	}
-	out, err := exec.Command("go", "env", "GOPATH").Output()
+	cmd := exec.Command("go", "env", "GOPATH")
+	out, err := cmd.Output()
 	if err != nil {
 		return "", err
 	}
@@ -119,21 +130,14 @@ func goBin() (string, error) {
 
 func installTools(binDir string, goMinorVersion int) error {
 	installCmd := "install"
-	if goMinorVersion < 16 {
-		installCmd = "get"
-	}
 
-	dir := ""
-	if installCmd == "get" { // run `go get` command from an empty directory.
-		dir = os.TempDir()
-	}
-	env := append(os.Environ(), "GO111MODULE=on")
+	// For tools installation, ensure GOTOOLCHAIN=auto.
+	env := append(os.Environ(), "GO111MODULE=on", "GOTOOLCHAIN=auto")
 	for _, tool := range tools {
 		ver := pickVersion(goMinorVersion, tool.versions, pickLatest(tool.path, tool.preferPreview))
 		path := tool.path + "@" + ver
 		cmd := exec.Command("go", installCmd, path)
 		cmd.Env = env
-		cmd.Dir = dir
 		fmt.Println("go", installCmd, path)
 		if out, err := cmd.CombinedOutput(); err != nil {
 			return fmt.Errorf("installing %v: %s\n%v", path, out, err)