Public Access
jaap-jan
53ff15ba86
The phone's terminal was blank whenever it was connected. Not slow, not mis-sized, not disconnected: a live session accepting keystrokes, acknowledging output and drawing nothing at all. ◆ THE WEBGL ADDON DOES NOT RECOVER FROM A LOST CONTEXT AND DOES NOT FAIL LOUDLY. It stays loaded over a dead context and renders an empty rectangle, which is xterm's documented behaviour and the reason its guidance is to subscribe to onContextLoss and dispose. This page never did, and until there was a phone there was no reason to notice. Losing the context is ordinary on Android and nearly unheard of on Windows, which is what made this a one-head bug in shared code. Collapsing the renderer sets the native view to GONE — Avalonia's AndroidNativeControlHostImpl.HideWithSize, read out of the assembly rather than guessed at — and a WebView with no surface has no GL context. The shell collapses it every time a tab starts connecting, every time the connect sheet opens and every time the app is backgrounded. Worse, the ordering guarantees it for the first session on every launch: OpenSessionAsync sends SESSION_OPENED before the tab reports a session, so IsTerminalShowing is still false and the pane, the terminal and its GL context are all built inside a collapsed WebView. WebView2 hides a child HWND and keeps rendering throughout, which docs/platform-flags.md measured at length. The addon is not reloaded after a loss. A pane that lost the context once is on a surface that will do it again, and thrashing between renderers is worse than being slow — the DOM renderer is what the existing fallback comment already argues for, because a blank pane is not usable and a slow one is. The comment above MINIMUM_FITTABLE_PIXELS was wrong for this head and is corrected with it. It asserted that collapsing the WebView leaves this page's viewport alone, so no observer fires and the guard protects nothing — true of a hidden child HWND, false of a GONE view, which its parent's layout skips outright. On the phone the guard is the only thing standing between a lock, a connect sheet or a trip to the background and a remote pty reflowed to 2x1. Also on the way past: the renderer-timeout message told phone users to install the Microsoft Edge WebView2 runtime. That is the other blank-terminal failure mode's message, and naming a runtime that cannot exist on the device is worse than saying nothing at the one moment somebody is trying to work out what went wrong. It now names Android's own WebView on that head, as a runtime check for the reason MainWindowViewModel.GestureWait records beside its own. Not verified on a device — there is no handset or emulator here, and no test covers this page. The diagnosis is the decompiled hide path plus xterm's own requirement, not an observation. 523 tests over the shell and the terminal pass, and both heads build.