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F14 — Window state & vetoable close ​

Minimize/maximize/fullscreen, focus, and the close request — the lifecycle edges. The exact event sequences for each transition are the deliverable; they feed event-sequences.md directly.

Requirements ​

  1. Keyboard shortcuts trigger: maximize toggle, minimize, fullscreen toggle, restore. Log the request AND every resulting event until the state settles:
    • Wayland: xdg_toplevel.set_maximized/set_fullscreen/set_minimized and the resulting configure states array (note: minimized is fire-and-forget — no state echo; that asymmetry is a finding).
    • X11: _NET_WM_STATE ClientMessages + WM_CHANGE_STATE; track _NET_WM_STATE property notifies and ConfigureNotify.
    • Win32: ShowWindow(SW_MAXIMIZE/SW_MINIMIZE), WM_SIZE wParams, WM_WINDOWPOSCHANGING/CHANGED order; fullscreen via the borderless-resize idiom (document it — Win32 has no fullscreen state).
    • macOS: zoom:, miniaturize:, toggleFullScreen: and the NSWindowDelegate/notification sequence (fullscreen is a Space transition — log its duration).
  2. Log focus/activation events (focus state=in|out reason=…) including which surface object carries focus (Wayland: wl_keyboard.enter vs xdg_toplevel activated state).
  3. Vetoable close: the demo has a "dirty" flag (toggled by a key). On close request (xdg_toplevel.close / WM_DELETE_WINDOW ClientMessage / WM_CLOSE / windowShouldClose:), if dirty: refuse once, log close_requested veto=1, clear the flag; second request closes. Record per platform whether veto is a first-class concept or an app-side convention (Wayland/X11: the request is purely advisory; Win32/macOS: explicit return-value contracts).
  4. Programmatic self-close paths must tear down cleanly (no protocol error, exit 0).

Instrumentation ​

state_request kind=…, state_changed states=[…], focus state=… , close_requested veto=0|1, plus configure/resize events.

Findings to record ​

  • One ordered sequence diagram (as a log excerpt) per transition per platform.
  • Which transitions echo back a state and which are fire-and-forget.
  • Who owns "fullscreen" (a real state vs a geometry idiom).
  • The veto contract per platform.

Verification ​

Wayland/X11: Tier A (headless weston honors state requests; Xvfb + a lightweight WM — run one, e.g. via nix shell nixpkgs#icewm — since bare Xvfb has no WM to answer _NET_WM_STATE; the no-WM behavior is itself worth one log). Win32: A[wine]. macOS: A[ssh] (fullscreen Space animation timing needs a real session — Tier C note).