Go 1.21 Upgrade

Fixes #11351

tpl/internal/go_templates/testenv/testenv_notwin.go

@@ -7,13 +7,39 @@
 package testenv
 
 import (
+	"fmt"
+	"os"
+	"path/filepath"
 	"runtime"
 )
 
 func hasSymlink() (ok bool, reason string) {
 	switch runtime.GOOS {
-	case "android", "plan9":
+	case "plan9":
 		return false, ""
+	case "android", "wasip1":
+		// For wasip1, some runtimes forbid absolute symlinks,
+		// or symlinks that escape the current working directory.
+		// Perform a simple test to see whether the runtime
+		// supports symlinks or not. If we get a permission
+		// error, the runtime does not support symlinks.
+		dir, err := os.MkdirTemp("", "")
+		if err != nil {
+			return false, ""
+		}
+		defer func() {
+			_ = os.RemoveAll(dir)
+		}()
+		fpath := filepath.Join(dir, "testfile.txt")
+		if err := os.WriteFile(fpath, nil, 0644); err != nil {
+			return false, ""
+		}
+		if err := os.Symlink(fpath, filepath.Join(dir, "testlink")); err != nil {
+			if SyscallIsNotSupported(err) {
+				return false, fmt.Sprintf("symlinks unsupported: %s", err.Error())
+			}
+			return false, ""
+		}
 	}
 
 	return true, ""