Firelink/TAURI3_SPIKE.md

Tauri 3 compatibility spike

• Date: 2026-10-14
• Status: report-only, isolated non-production experiment
• Production decision: Firelink remains on stable Tauri 2

This report records the result of an isolated Tauri 3 alpha experiment. The alpha dependency and source changes used for the experiment are intentionally not part of the production refresh.

Findings

The main migration shape is tractable: add a direct runtime crate, select Wry on the builder, and replace tauri::Wry type parameters with tauri::DynRuntime. Firelink's command dispatcher, setup, tray/menu code, capability files, and macOS run-event handling compiled with that model.

The blocking incompatibility is tauri-plugin-shell alpha.2. Firelink relies on .set_process_group(true) for media subprocesses and tests that killing a launcher also kills its descendants. The alpha crate has no such method or process-group/job-object implementation. A normal cargo check --lib failed at src/lib.rs:2779 with:

error[E0599]: no method named `set_process_group` found for struct `tauri_plugin_shell::process::Command`

The same API is used by the shell regression test and tests/shell_process_group.rs. Removing those calls only for diagnosis let the remaining code compile, but would discard Unix process-group and Windows Job Object behavior. The calls were restored; the alpha migration is not release-safe until the plugin restores that contract or Firelink adopts a separately validated process supervisor.

Dependency and runtime surface

The official Tauri 2-to-3 alpha migration guide requires Rust 1.95 or newer, explicit runtime selection, and v3 alpha plugins. The registry versions were staggered on 2026-10-14:

Component	Spike version
tauri / tauri-runtime-wry	3.0.0-alpha.4
tauri-build	3.0.0-alpha.3
Rust dialog plugin	3.0.0-alpha.3
Rust opener, shell, notification, clipboard-manager, deep-link, single-instance, log plugins	3.0.0-alpha.2
@tauri-apps/api / CLI	3.0.0-alpha.2 / 3.0.0-alpha.4

The installed Rust toolchain was 1.99.0, above the documented MSRV. The selected runtime was Wry; tauri info reported Wry 0.57.0 and Tao 0.37.1, with no CEF runtime detected. The generated Firelink TypeScript bindings are ts-rs domain types rather than Tauri invoke-handler types and needed no regeneration.

Migration surface by feature

• Plugins and capabilities resolved at their v3 alpha versions. Existing default.json and properties.json permissions passed the Tauri config check; no capability edit was needed.
• The main and Properties windows, menus, tray, and macOS run-event path compiled with DynRuntime.
• The firelink and magnet schemes plus deep-link and single-instance plugins resolved on macOS. Windows/Linux protocol forwarding was not runtime-tested.
• Notification and clipboard plugins compiled. The shell plugin's process ownership contract is the blocker above.
• The existing THIRD_PARTY_NOTICES.md and engine-dist/ resource mappings were accepted by configuration checks, but resource lookup was not exercised in a running or packaged app.
• Wry still uses WKWebView on macOS, WebView2 on Windows, and WebKitGTK on Linux. The current release matrix remains macOS arm64 DMG, Windows x64 NSIS, and Linux x64 AppImage/deb/rpm. Linux tray behavior still needs native desktop-environment validation; the current workflow's libappindicator dependency should only be removed after that validation.

Probes and limits

• npm run build passed with the v3 alpha JS packages.
• Tauri CLI version/config/runtime detection passed.
• cargo check --lib and cargo check --all-targets failed only at the restored shell process-group calls; with those calls temporarily removed for diagnosis, both checks passed after updating tauri::Wry references.
• A Windows cross-target check stopped in ring because this macOS host lacks Windows SDK headers. Linux package checks were unavailable because this host lacks WebKitGTK/GTK/Ayatana AppIndicator development modules.
• No app launch or native package was produced. Package size, startup, resource placement, deep-link delivery, clipboard/notification behavior, and Windows/Linux packaging remain unmeasured.

Required next validation

Preserve process-group/job-object cancellation semantics while resolving the shell-plugin gap, then run the existing Rust tests and packaged smoke checks on native macOS arm64, Windows x64, and Ubuntu 22.04 Linux x64. Include Linux tray validation, deep-link/single-instance launch checks, staged-engine resource-path verification, and before/after artifact-size measurements. Keep the alpha dependency/configuration experiment isolated until those results and upstream plugin compatibility are resolved.