// Copyright 2016 The Go Authors. All rights reserved. // Use of this source code is governed by a BSD-style // license that can be found in the LICENSE file. //go:build !windows package testenv import ( "fmt" "os" "path/filepath" "runtime" "sync" ) var hasSymlink = sync.OnceValues(func() (ok bool, reason string) { switch runtime.GOOS { 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, "" })