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
@@ -270,12 +271,23 @@ func (conn *SSHConn) GetName() string {
 func (conn *SSHConn) OpenDomainSocketListener(ctx context.Context) error {
 	conn.Infof(ctx, "running OpenDomainSocketListener...\n")
 	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 != "" {
+			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 conn.DomainSockListener != nil && conn.DomainSockName != "" {
+		conn.Infof(ctx, "domain socket already active (%s)\n", conn.DomainSockName)
+		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 +1087,7 @@ 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 +1138,37 @@ 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()
+					return wshutil.DefaultRouter.WaitForRegister(waitCtx, routeId)
+				}
+				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 +108,93 @@ func ExitCodeFromWaitErr(err error) int {
 
 }
 
+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()
+}
+
+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)
+}
+
+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 $HOME being correct on the remote shell.
+		rest := cwd[1:] // includes leading "/"
+		return "~" + sshUser + rest
+	}
+	return posixCwdExpr(cwd)
+}
+
+func fishCwdExpr(cwd string) string {
+	cwd = strings.TrimSpace(cwd)
+	if cwd == "" {
+		return ""
+	}
+	if cwd == "~" {
+		return "~"
+	}
+	if strings.HasPrefix(cwd, "~/") {
+		return cwd // fish auto-expands ~ correctly
+	}
+	return utilfn.ShellQuote(cwd, false, -1)
+}
+
+func pwshCwdExpr(cwd string) string {
+	cwd = strings.TrimSpace(cwd)
+	if cwd == "" {
+		return ""
+	}
+	// PowerShell uses ~ correctly by default
+	if cwd == "~" || strings.HasPrefix(cwd, "~/") {
+		return cwd
+	}
+	// PowerShell paths should be wrapped in single quotes to handle special characters
+	if strings.ContainsAny(cwd, " \"'`$") {
+		return "'" + strings.ReplaceAll(cwd, "'", "''") + "'"
+	}
+	return cwd
+}
+
 func checkCwd(cwd string) error {
 	if cwd == "" {
 		return fmt.Errorf("cwd is empty")

pkg/shellexec/shellexec_test.go

@@ -0,0 +1,54 @@
+// Copyright 2026, Command Line Inc.
+// SPDX-License-Identifier: Apache-2.0
+
+package shellexec
+
+import "testing"
+
+func TestPosixCwdExprNoWshRemote(t *testing.T) {
+	tests := []struct {
+		name    string
+		cwd     string
+		sshUser string
+		want    string
+	}{
+		{
+			name:    "tilde-dir-uses-username-home",
+			cwd:     "~/.ssh",
+			sshUser: "root",
+			want:    "~root/.ssh",
+		},
+		{
+			name:    "tilde-root-uses-username-home",
+			cwd:     "~",
+			sshUser: "root",
+			want:    "~root",
+		},
+		{
+			name:    "tilde-slash-uses-username-home",
+			cwd:     "~/",
+			sshUser: "root",
+			want:    "~root/",
+		},
+		{
+			name:    "non-tilde-falls-back",
+			cwd:     "/var/log",
+			sshUser: "root",
+			want:    "/var/log",
+		},
+		{
+			name:    "missing-user-falls-back-to-home-var",
+			cwd:     "~/.ssh",
+			sshUser: "",
+			want:    "\"$HOME/.ssh\"",
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := posixCwdExprNoWshRemote(tt.cwd, tt.sshUser)
+			if got != tt.want {
+				t.Fatalf("posixCwdExprNoWshRemote(%q, %q)=%q, want %q", tt.cwd, tt.sshUser, got, tt.want)
+			}
+		})
+	}
+}