fix(sandbox): resolve bundled boxlite via real executable path

- use the resolved executable path when locating the sibling bundled `boxlite` binary
- add a regression test for the symlinked install layout

Author: RussellLuo

internal/sandbox/boxlitecli/resolve.go

@@ -32,10 +32,33 @@ func bundledPath() string {
 	if err != nil {
 		return ""
 	}
-	candidate := filepath.Join(filepath.Dir(exe), defaultCLIPath)
+
+	for _, exePath := range executablePathCandidates(exe) {
+		candidate := filepath.Join(filepath.Dir(exePath), defaultCLIPath)
+		if isExecutableFile(candidate) {
+			return candidate
+		}
+	}
+	return ""
+}
+
+func executablePathCandidates(exe string) []string {
+	exe = strings.TrimSpace(exe)
+	if exe == "" {
+		return nil
+	}
+
+	candidates := []string{exe}
+	if resolved, err := filepath.EvalSymlinks(exe); err == nil && resolved != "" && resolved != exe {
+		candidates = append(candidates, resolved)
+	}
+	return candidates
+}
+
+func isExecutableFile(candidate string) bool {
 	info, err := os.Stat(candidate)
 	if err != nil || info.IsDir() {
-		return ""
+		return false
 	}
-	return candidate
+	return info.Mode()&0o111 != 0
 }

internal/sandbox/boxlitecli/resolve_test.go

@@ -51,6 +51,41 @@ func TestResolvePathUsesBundledBinaryWhenUnset(t *testing.T) {
 	}
 }
 
+func TestResolvePathUsesBundledBinaryBehindExecutableSymlink(t *testing.T) {
+	dir := t.TempDir()
+	installBinDir := filepath.Join(dir, "local", "bin")
+	bundleBinDir := filepath.Join(dir, "local", "lib", "csgclaw", "v0.2.6", "csgclaw", "bin")
+	if err := os.MkdirAll(installBinDir, 0o755); err != nil {
+		t.Fatalf("MkdirAll(install) error = %v", err)
+	}
+	if err := os.MkdirAll(bundleBinDir, 0o755); err != nil {
+		t.Fatalf("MkdirAll(bundle) error = %v", err)
+	}
+
+	realExecutable := filepath.Join(bundleBinDir, "csgclaw")
+	if err := os.WriteFile(realExecutable, []byte(""), 0o755); err != nil {
+		t.Fatalf("WriteFile(csgclaw) error = %v", err)
+	}
+	bundled := filepath.Join(bundleBinDir, defaultCLIPath)
+	if err := os.WriteFile(bundled, []byte(""), 0o755); err != nil {
+		t.Fatalf("WriteFile(boxlite) error = %v", err)
+	}
+	executableSymlink := filepath.Join(installBinDir, "csgclaw")
+	if err := os.Symlink(realExecutable, executableSymlink); err != nil {
+		t.Fatalf("Symlink() error = %v", err)
+	}
+	restore := stubExecutablePath(t, executableSymlink)
+	defer restore()
+
+	want, err := filepath.EvalSymlinks(bundled)
+	if err != nil {
+		t.Fatalf("EvalSymlinks(boxlite) error = %v", err)
+	}
+	if got := ResolvePath(""); got != want {
+		t.Fatalf("ResolvePath(\"\") = %q, want %q", got, want)
+	}
+}
+
 func TestResolvePathFallsBackToPATHValue(t *testing.T) {
 	restore := stubExecutablePath(t, filepath.Join(t.TempDir(), "bin", "csgclaw"))
 	defer restore()