[bin wrappers] Fixes: don't export PATH, and eval the symlink of the binary

internal/wrapnix/wrapper.go

@@ -55,15 +55,19 @@ func CreateWrappers(ctx context.Context, devbox devboxer) error {
 	if err != nil {
 		return err
 	}
+	devboxSymlinkDir := ""
+	if devboxSymlinkPath != "" { // may be empty if not possible to create symlink
+		devboxSymlinkDir = filepath.Dir(devboxSymlinkPath)
+	}
 
 	for _, bin := range bins {
 		if err = createWrapper(&createWrapperArgs{
-			devboxer:         devbox,
-			BashPath:         bashPath,
-			Command:          bin,
-			ShellEnvHash:     shellEnvHash,
-			DevboxSymlinkDir: filepath.Dir(devboxSymlinkPath),
-			destPath:         filepath.Join(destPath, filepath.Base(bin)),
+			devboxer:                 devbox,
+			BashPath:                 bashPath,
+			Command:                  bin,
+			ShellEnvHash:             shellEnvHash,
+			DevboxSymlinkDirIfExists: devboxSymlinkDir,
+			destPath:                 filepath.Join(destPath, filepath.Base(bin)),
 		}); err != nil {
 			return errors.WithStack(err)
 		}
@@ -72,7 +76,8 @@ func CreateWrappers(ctx context.Context, devbox devboxer) error {
 	return createSymlinksForSupportDirs(devbox.ProjectDir())
 }
 
-// CreateDevboxSymlink creates a symlink to the devbox binary
+// CreateDevboxSymlink creates a symlink to the devbox binary. It may return an
+// empty string if it could not create the symlink.
 //
 // Needed because:
 //
@@ -89,22 +94,33 @@ func CreateWrappers(ctx context.Context, devbox devboxer) error {
 //     So, the bin-wrappers need to use a symlink to the latest devbox binary. This
 //     symlink is updated when devbox is updated.
 func CreateDevboxSymlink() (string, error) {
+	// Get the symlink path; create the symlink directory if it doesn't exist.
 	curDir := xdg.CacheSubpath(filepath.Join("devbox", "bin", "current"))
 	if err := fileutil.EnsureDirExists(curDir, 0755, false /*chmod*/); err != nil {
 		return "", err
 	}
 	currentDevboxSymlinkPath := filepath.Join(curDir, "devbox")
 
-	devboxBinaryPath, err := os.Executable()
+	// Get the path to the devbox binary.
+	execPath, err := os.Executable()
 	if err != nil {
 		return "", errors.WithStack(err)
 	}
+	devboxBinaryPath, evalSymlinkErr := filepath.EvalSymlinks(execPath)
+	// we check the error below, because we always want to remove the symlink
 
 	// We will always re-create this symlink to ensure correctness.
 	if err := os.Remove(currentDevboxSymlinkPath); err != nil && !errors.Is(err, os.ErrNotExist) {
 		return "", errors.WithStack(err)
 	}
 
+	if evalSymlinkErr != nil {
+		// This may return an error due to symlink loops. In that case, we
+		// return an empty string, and the bin-wrapper should handle it accordingly.
+		// nolint:nilerr
+		return "", nil
+	}
+
 	// Don't return error if error is os.ErrExist to protect against race conditions.
 	if err := os.Symlink(devboxBinaryPath, currentDevboxSymlinkPath); err != nil && !errors.Is(err, os.ErrExist) {
 		return "", errors.WithStack(err)
@@ -115,11 +131,11 @@ func CreateDevboxSymlink() (string, error) {
 
 type createWrapperArgs struct {
 	devboxer
-	BashPath         string
-	Command          string
-	ShellEnvHash     string
-	DevboxSymlinkDir string
-	destPath         string
+	BashPath                 string
+	Command                  string
+	ShellEnvHash             string
+	DevboxSymlinkDirIfExists string
+	destPath                 string
 }
 
 func createWrapper(args *createWrapperArgs) error {

internal/wrapnix/wrapper.sh.tmpl

@@ -1,6 +1,8 @@
 #!{{ .BashPath }}
 
-export PATH="{{ .DevboxSymlinkDir }}:$PATH"
+{{ if ne .DevboxSymlinkDirIfExists "" }}
+PATH="{{ .DevboxSymlinkDirIfExists }}:$PATH"
+{{ end }}
 
 {{/*
 # If env variable has never been set by devbox we set it, but also