Swift 6 language mode and a consistent macOS 14 baseline

[matijazezelj]

Stacked on #63. The first two commits here are that PR; only the last two are new. It won't compile without #63, because the scrollEdgeEffectHidden rename lives there. Merge #63 first and this rebases cleanly — or close this if the tradeoff below isn't one you want.

The one thing to decide first

This raises the minimum macOS from 13 to 14. That is a product call, not a technical one, so it's entirely yours — everything else here follows from it, and I've kept it in separate commits so you can take the parts you want.

Worth knowing: the current setting is already inconsistent. MACOSX_DEPLOYMENT_TARGET is 14.4 in both project-level configs but 13.0 in both target-level ones, and target-level wins — so the effective minimum today is 13.0, while the project level advertises 14.4. Whichever way you go, those four values should agree.

What raising it buys

Two availability shims become dead code and are deleted outright — 90 lines, including a whole NSViewRepresentable keyboard fallback:

• View+OnKeyPress.swift → call onKeyPress directly
• View+FocusEffectDisabled.swift → call focusEffectDisabled directly

The deprecated single-parameter onChange(of:perform:) at ShortcutButton.swift:25 and GeneralTab.swift:203 moves to the two-parameter form, which needs macOS 14.

Two overrides declared in extensions

These are worth a look regardless of the baseline question. Overriding a method from an extension of an Objective-C class is undefined behaviour in Swift — if more than one such override exists, which one wins is not defined.

• BrowserinoWindow.swift:51 forced canBecomeKey to true on every NSPanel in the process, which includes the open and save panels behind fileImporter. Moved onto BrowserinoWindow, the only panel that actually needs it (its .nonactivatingPanel style is what refuses key status).
• PreferencesView.swift:12 overrode NSTableView.viewDidMoveToWindow app-wide to clear List backgrounds. Replaced with .scrollContentBackground(.hidden) on the four Lists it existed to serve — the sanctioned API, available since macOS 13.

Swift 6 language mode

SWIFT_VERSION 5.0 → 6.0. AppDelegate becomes @MainActor, which resolves 15 of 16 isolation warnings. The sixteenth is observeValue, deliberately left nonisolated with a hop to the main actor inside: defaults written by another process deliver KVO off the main thread, so MainActor.assumeIsolated would trap there. That isn't hypothetical — it fires if you edit Browserino's rules with defaults write while the app is running.

Three further fixes that only appear in a full compile, never in -typecheck:

• BrowserUtil's static @AppStorage properties are nonisolated global mutable state (a hard error in Swift 6). The type is only ever used from the main actor, so it's isolated there.
• SettingsDocument held [String: Any] while FileDocument requires Sendable. It now serializes on the way in and carries Data; the exporter wrote the same pretty-printed JSON either way.
• setDefaultApplication's completion handler is a @Sendable closure and cannot touch @State or call a main-actor method, so it hops before updating isDefault.

Verification

Compiles with 0 errors and 0 warnings in Swift 6 mode against the macOS 26.5 SDK, targeting macOS 14.0, and the resulting app has been running as my default browser on macOS 27.

Not verified, and worth your eyes: the List backgrounds under scrollContentBackground(.hidden), shortcut recording via the direct onKeyPress, and the menu-bar toggle, which is now one main-actor hop later than before. I had no way to screenshot the running UI on this machine.

LastUpgradeCheck is deliberately untouched — Xcode rewrites it itself when you accept its recommended-settings prompt, and setting it by hand without Xcode validating those settings would be a lie in the file.

Disclosure

Written with AI assistance (Claude Code), same as #63. Everything above was compiled and run before submitting. This one is much more opinionated than #63, so treat it as a proposal rather than a fix — no hard feelings if the baseline bump isn't where you want to go.