fix: keep permissions profiles forward compatible (#14107)

## Summary
- preserve unknown `:special_path` tokens, including nested entries, so
older Codex builds warn and ignore instead of failing config load
- fail closed with a startup warning when a permissions profile has
missing or empty filesystem entries instead of aborting profile
compilation
- normalize Windows verbatim paths like `\?\C:\...` before absolute-path
validation while keeping explicit errors for truly invalid paths

## Testing
- just fmt
- cargo test -p codex-core permissions_profiles_allow
- cargo test -p codex-core
normalize_absolute_path_for_platform_simplifies_windows_verbatim_paths
- cargo test -p codex-protocol
unknown_special_paths_are_ignored_by_legacy_bridge
- cargo clippy -p codex-core -p codex-protocol --all-targets -- -D
warnings
- cargo clean

codex-rs/core/src/config/config_tests.rs

@@ -574,6 +574,156 @@ fn permissions_profiles_reject_nested_entries_for_non_project_roots() -> std::io
     Ok(())
 }
 
+fn load_workspace_permission_profile(profile: PermissionProfileToml) -> std::io::Result<Config> {
+    let codex_home = TempDir::new()?;
+    let cwd = TempDir::new()?;
+    std::fs::write(cwd.path().join(".git"), "gitdir: nowhere")?;
+
+    Config::load_from_base_config_with_overrides(
+        ConfigToml {
+            default_permissions: Some("workspace".to_string()),
+            permissions: Some(PermissionsToml {
+                entries: BTreeMap::from([("workspace".to_string(), profile)]),
+            }),
+            ..Default::default()
+        },
+        ConfigOverrides {
+            cwd: Some(cwd.path().to_path_buf()),
+            ..Default::default()
+        },
+        codex_home.path().to_path_buf(),
+    )
+}
+
+#[test]
+fn permissions_profiles_allow_unknown_special_paths() -> std::io::Result<()> {
+    let config = load_workspace_permission_profile(PermissionProfileToml {
+        filesystem: Some(FilesystemPermissionsToml {
+            entries: BTreeMap::from([(
+                ":future_special_path".to_string(),
+                FilesystemPermissionToml::Access(FileSystemAccessMode::Read),
+            )]),
+        }),
+        network: None,
+    })?;
+
+    assert_eq!(
+        config.permissions.file_system_sandbox_policy,
+        FileSystemSandboxPolicy::restricted(vec![FileSystemSandboxEntry {
+            path: FileSystemPath::Special {
+                value: FileSystemSpecialPath::unknown(":future_special_path", None),
+            },
+            access: FileSystemAccessMode::Read,
+        }]),
+    );
+    assert_eq!(
+        config.permissions.sandbox_policy.get(),
+        &SandboxPolicy::ReadOnly {
+            access: ReadOnlyAccess::Restricted {
+                include_platform_defaults: false,
+                readable_roots: Vec::new(),
+            },
+            network_access: false,
+        }
+    );
+    assert!(
+        config.startup_warnings.iter().any(|warning| warning.contains(
+            "Configured filesystem path `:future_special_path` is not recognized by this version of Codex and will be ignored."
+        )),
+        "{:?}",
+        config.startup_warnings
+    );
+    Ok(())
+}
+
+#[test]
+fn permissions_profiles_allow_unknown_special_paths_with_nested_entries() -> std::io::Result<()> {
+    let config = load_workspace_permission_profile(PermissionProfileToml {
+        filesystem: Some(FilesystemPermissionsToml {
+            entries: BTreeMap::from([(
+                ":future_special_path".to_string(),
+                FilesystemPermissionToml::Scoped(BTreeMap::from([(
+                    "docs".to_string(),
+                    FileSystemAccessMode::Read,
+                )])),
+            )]),
+        }),
+        network: None,
+    })?;
+
+    assert_eq!(
+        config.permissions.file_system_sandbox_policy,
+        FileSystemSandboxPolicy::restricted(vec![FileSystemSandboxEntry {
+            path: FileSystemPath::Special {
+                value: FileSystemSpecialPath::unknown(":future_special_path", Some("docs".into())),
+            },
+            access: FileSystemAccessMode::Read,
+        }]),
+    );
+    assert!(
+        config.startup_warnings.iter().any(|warning| warning.contains(
+            "Configured filesystem path `:future_special_path` with nested entry `docs` is not recognized by this version of Codex and will be ignored."
+        )),
+        "{:?}",
+        config.startup_warnings
+    );
+    Ok(())
+}
+
+#[test]
+fn permissions_profiles_allow_missing_filesystem_with_warning() -> std::io::Result<()> {
+    let config = load_workspace_permission_profile(PermissionProfileToml {
+        filesystem: None,
+        network: None,
+    })?;
+
+    assert_eq!(
+        config.permissions.file_system_sandbox_policy,
+        FileSystemSandboxPolicy::restricted(Vec::new())
+    );
+    assert_eq!(
+        config.permissions.sandbox_policy.get(),
+        &SandboxPolicy::ReadOnly {
+            access: ReadOnlyAccess::Restricted {
+                include_platform_defaults: false,
+                readable_roots: Vec::new(),
+            },
+            network_access: false,
+        }
+    );
+    assert!(
+        config.startup_warnings.iter().any(|warning| warning.contains(
+            "Permissions profile `workspace` does not define any recognized filesystem entries for this version of Codex."
+        )),
+        "{:?}",
+        config.startup_warnings
+    );
+    Ok(())
+}
+
+#[test]
+fn permissions_profiles_allow_empty_filesystem_with_warning() -> std::io::Result<()> {
+    let config = load_workspace_permission_profile(PermissionProfileToml {
+        filesystem: Some(FilesystemPermissionsToml {
+            entries: BTreeMap::new(),
+        }),
+        network: None,
+    })?;
+
+    assert_eq!(
+        config.permissions.file_system_sandbox_policy,
+        FileSystemSandboxPolicy::restricted(Vec::new())
+    );
+    assert!(
+        config.startup_warnings.iter().any(|warning| warning.contains(
+            "Permissions profile `workspace` does not define any recognized filesystem entries for this version of Codex."
+        )),
+        "{:?}",
+        config.startup_warnings
+    );
+    Ok(())
+}
+
 #[test]
 fn permissions_profiles_reject_project_root_parent_traversal() -> std::io::Result<()> {
     let codex_home = TempDir::new()?;