fix: prevent "no route for conn:..." errors and add shell path expansion

- Auto-recover wsh routes after connserver restart
- Allow domain socket listener reuse when already established
- Add WshEnsuring flag to prevent thundering herd
- Add shell-specific path expansion (posix, fish, pwsh) with tilde (~) support
- Add escapeForPosixDoubleQuotes for safe path quoting
- Add unit tests for path expansion logic

Author: re2zero

pkg/remote/conncontroller/conncontroller.go

@@ -80,6 +80,7 @@ type SSHConn struct {
 	Status             string
 	ConnHealthStatus   string
 	WshEnabled         *atomic.Bool
+	WshEnsuring        *atomic.Bool
 	Opts               *remote.SSHOpts
 	Client             *ssh.Client
 	DomainSockName     string // if "", then no domain socket
@@ -269,13 +270,28 @@ func (conn *SSHConn) GetName() string {
 
 func (conn *SSHConn) OpenDomainSocketListener(ctx context.Context) error {
 	conn.Infof(ctx, "running OpenDomainSocketListener...\n")
+	var existingListener net.Listener
+	var existingSockName string
 	allowed := WithLockRtn(conn, func() bool {
+		// If it's already set up, allow callers to reuse it even if the conn is already connected.
+		if conn.DomainSockListener != nil && conn.DomainSockName != "" {
+			existingListener = conn.DomainSockListener
+			existingSockName = conn.DomainSockName
+			return true
+		}
 		return conn.Status == Status_Connecting
 	})
 	if !allowed {
 		return fmt.Errorf("cannot open domain socket for %q when status is %q", conn.GetName(), conn.GetStatus())
 	}
+	if existingListener != nil && existingSockName != "" {
+		conn.Infof(ctx, "domain socket already active (%s)\n", existingSockName)
+		return nil
+	}
 	client := conn.GetClient()
+	if client == nil {
+		return fmt.Errorf("cannot open domain socket for %q: ssh client is not connected", conn.GetName())
+	}
 	randStr, err := utilfn.RandomHexString(16) // 64-bits of randomness
 	if err != nil {
 		return fmt.Errorf("error generating random string: %w", err)
@@ -1075,6 +1091,7 @@ func getConnInternal(opts *remote.SSHOpts, createIfNotExists bool) *SSHConn {
 			Status:           Status_Init,
 			ConnHealthStatus: ConnHealthStatus_Good,
 			WshEnabled:       &atomic.Bool{},
+			WshEnsuring:      &atomic.Bool{},
 			Opts:             opts,
 		}
 		clientControllerMap[*opts] = rtn
@@ -1125,6 +1142,40 @@ func EnsureConnection(ctx context.Context, connName string) error {
 	connStatus := conn.DeriveConnStatus()
 	switch connStatus.Status {
 	case Status_Connected:
+		// If wsh is enabled for this connection, ensure the connserver route exists.
+		// This prevents "no route for \"conn:...\"" errors when using remote file browsing after a
+		// connserver restart/termination.
+		enableWsh, _ := conn.getConnWshSettings()
+		if enableWsh {
+			routeId := wshutil.MakeConnectionRouteId(conn.GetName())
+			fastCtx, cancelFn := context.WithTimeout(ctx, 75*time.Millisecond)
+			fastErr := wshutil.DefaultRouter.WaitForRegister(fastCtx, routeId)
+			cancelFn()
+			if fastErr != nil {
+				// Avoid a thundering herd when multiple blocks ensure concurrently.
+				if conn.WshEnsuring != nil && !conn.WshEnsuring.CompareAndSwap(false, true) {
+					waitCtx, cancelWait := context.WithTimeout(ctx, 5*time.Second)
+					defer cancelWait()
+					if err := wshutil.DefaultRouter.WaitForRegister(waitCtx, routeId); err != nil {
+						return fmt.Errorf("waiting for concurrent wsh setup for %q: %w", conn.GetName(), err)
+					}
+					return nil
+				}
+				if conn.WshEnsuring != nil {
+					defer conn.WshEnsuring.Store(false)
+				}
+				wshResult := conn.tryEnableWsh(ctx, conn.GetName())
+				conn.persistWshInstalled(ctx, wshResult)
+				if !wshResult.WshEnabled {
+					if wshResult.WshError != nil {
+						return wshResult.WshError
+					}
+					if wshResult.NoWshReason != "" {
+						return fmt.Errorf("wsh unavailable for %q: %s", conn.GetName(), wshResult.NoWshReason)
+					}
+				}
+			}
+		}
 		return nil
 	case Status_Connecting:
 		return conn.WaitForConnect(ctx)

pkg/shellexec/shellexec.go

@@ -26,6 +26,7 @@ import (
 	"github.com/wavetermdev/waveterm/pkg/remote/conncontroller"
 	"github.com/wavetermdev/waveterm/pkg/util/pamparse"
 	"github.com/wavetermdev/waveterm/pkg/util/shellutil"
+	"github.com/wavetermdev/waveterm/pkg/util/utilfn"
 	"github.com/wavetermdev/waveterm/pkg/wavebase"
 	"github.com/wavetermdev/waveterm/pkg/waveobj"
 	"github.com/wavetermdev/waveterm/pkg/wshrpc"
@@ -107,6 +108,115 @@ func ExitCodeFromWaitErr(err error) int {
 
 }
 
+// escapeForPosixDoubleQuotes escapes special characters for use inside POSIX double quotes.
+// It escapes: \\, ", $, and ` to be safe inside "$HOME<rest>" where <rest> should be treated literally.
+func escapeForPosixDoubleQuotes(s string) string {
+	// Conservative escaping for the subset of chars that are special inside double quotes.
+	// This is used for "$HOME<rest>" where <rest> should be treated literally.
+	var b strings.Builder
+	b.Grow(len(s))
+	for i := 0; i < len(s); i++ {
+		switch s[i] {
+		case '\\', '"', '$', '`':
+			b.WriteByte('\\')
+			b.WriteByte(s[i])
+		default:
+			b.WriteByte(s[i])
+		}
+	}
+	return b.String()
+}
+
+// posixCwdExpr returns a POSIX shell expression for the given current working directory.
+// It handles tilde (~) expansion by using $HOME for paths starting with ~/, and quotes other paths appropriately.
+func posixCwdExpr(cwd string) string {
+	cwd = strings.TrimSpace(cwd)
+	if cwd == "" {
+		return ""
+	}
+	if cwd == "~" {
+		return "~"
+	}
+	if strings.HasPrefix(cwd, "~/") {
+		// "~" must be expanded on the target machine. Use $HOME so we can still quote paths with spaces safely.
+		rest := cwd[1:] // includes leading "/"
+		return fmt.Sprintf("\"$HOME%s\"", escapeForPosixDoubleQuotes(rest))
+	}
+	return utilfn.ShellQuote(cwd, false, -1)
+}
+
+// posixCwdExprNoWshRemote returns a POSIX shell expression for the given current working directory on a remote SSH connection.
+// It uses ~user syntax for tilde paths when an SSH username is provided, avoiding dependency on $HOME on the remote shell.
+func posixCwdExprNoWshRemote(cwd string, sshUser string) string {
+	cwd = strings.TrimSpace(cwd)
+	if cwd == "" {
+		return ""
+	}
+	sshUser = strings.TrimSpace(sshUser)
+	if sshUser == "" {
+		return posixCwdExpr(cwd)
+	}
+	if cwd == "~" {
+		// Prefer ~user so we don't depend on $HOME being correct on the remote shell.
+		return "~" + sshUser
+	}
+	if cwd == "~/" {
+		return "~" + sshUser + "/"
+	}
+	if strings.HasPrefix(cwd, "~/") {
+		// Prefer ~user so we don't depend on $HOME being correct on the remote shell.
+		rest := cwd[1:] // includes leading "/"
+		if strings.ContainsAny(rest, " \t\n\r'\"`$&|;<>()\\*[]?!") {
+			// Quote the rest to handle spaces and special characters
+			return "~" + sshUser + "'" + strings.ReplaceAll(rest, "'", "''") + "'"
+		}
+		return "~" + sshUser + rest
+	}
+	return posixCwdExpr(cwd)
+}
+
+// fishCwdExpr returns a Fish shell expression for the given current working directory.
+// Fish requires $HOME for tilde paths in double-quoted strings to handle spaces safely.
+func fishCwdExpr(cwd string) string {
+	cwd = strings.TrimSpace(cwd)
+	if cwd == "" {
+		return ""
+	}
+	if cwd == "~" {
+		return "~"
+	}
+	if strings.HasPrefix(cwd, "~/") {
+		// Fish does not expand ~ inside double quotes, use $HOME instead
+		rest := cwd[1:] // includes leading "/"
+		return fmt.Sprintf("\"$HOME%s\"", escapeForPosixDoubleQuotes(rest))
+	}
+	return utilfn.ShellQuote(cwd, false, -1)
+}
+
+// pwshCwdExpr returns a PowerShell expression for the given current working directory.
+// PowerShell uses ~ correctly by default; paths with spaces or special characters are wrapped in quotes.
+func pwshCwdExpr(cwd string) string {
+	cwd = strings.TrimSpace(cwd)
+	if cwd == "" {
+		return ""
+	}
+	if cwd == "~" {
+		return "~"
+	}
+	if strings.HasPrefix(cwd, "~/") {
+		rest := cwd[1:]
+		if strings.ContainsAny(rest, " \"'`$()[]{}") {
+			// Use single quotes for the path portion to escape special characters
+			return "~'" + strings.ReplaceAll(rest, "'", "''") + "'"
+		}
+		return cwd
+	}
+	if strings.ContainsAny(cwd, " \"'`$()[]{}") {
+		return "'" + strings.ReplaceAll(cwd, "'", "''") + "'"
+	}
+	return cwd
+}
+
 func checkCwd(cwd string) error {
 	if cwd == "" {
 		return fmt.Errorf("cwd is empty")