exec-server: carry filesystem sandbox profiles

codex-rs/exec-server/tests/file_system.rs

@@ -25,6 +25,7 @@ use codex_protocol::models::FileSystemPermissions;
 use codex_protocol::models::PermissionProfile;
 use codex_protocol::protocol::ReadOnlyAccess;
 use codex_protocol::protocol::SandboxPolicy;
+use codex_sandboxing::policy_transforms::merge_permission_profiles;
 use codex_utils_absolute_path::AbsolutePathBuf;
 use pretty_assertions::assert_eq;
 use tempfile::TempDir;
@@ -567,13 +568,19 @@ async fn file_system_sandboxed_write_allows_additional_write_root(use_remote: bo
     std::fs::create_dir_all(&writable_dir)?;
 
     let mut sandbox = read_only_sandbox(readable_dir);
-    sandbox.additional_permissions = Some(PermissionProfile {
+    let additional_permissions = PermissionProfile {
         network: None,
         file_system: Some(FileSystemPermissions::from_read_write_roots(
             /*read*/ None,
             Some(vec![absolute_path(writable_dir)]),
         )),
-    });
+    };
+    let Some(permissions) =
+        merge_permission_profiles(Some(&sandbox.permissions), Some(&additional_permissions))
+    else {
+        panic!("merged permissions should not be empty");
+    };
+    sandbox.permissions = permissions;
 
     file_system
         .write_file(