Ptyxis 50.x (the new default terminal on Ubuntu 26.04) ships with
VTE 0.84.x, which parses the `\x1b[?2026h` / `\x1b[?2026l` synchronized-
output begin/end pair but still flashes the entire viewport on every
wrapped frame instead of deferring rendering. gnome-terminal 3.58 on
the same VTE renders cleanly, so the heuristic stays narrow: trigger
only on TERM_PROGRAM matching `ptyxis` (case-insensitive) or
PTYXIS_VERSION non-empty.
Add a new `synchronized_output` setting (`auto` | `on` | `off`,
default `auto`) controlling whether the renderer wraps each frame in
DEC 2026. `apply_env_overrides` flips `auto` → `off` when Ptyxis is
detected; the four wrapping sites in ui.rs (`draw_app_frame_inner`,
`reset_terminal_viewport`, `resume_terminal`, and the early-init
viewport reset) now respect the resolved flag. Users on Ptyxis who
upgrade past an upstream fix or want to confirm one landed can
override with `/set synchronized_output on`.
8 new tests cover: default-auto resolves enabled, off disables,
on stays enabled, set/aliases, Ptyxis via TERM_PROGRAM, Ptyxis via
PTYXIS_VERSION alone, explicit `on` beats the heuristic, explicit
`off` is preserved, and no non-Ptyxis TERM_PROGRAM (including Ghostty
and VS Code, which both keep DEC 2026 on) regresses.
Reported via WeChat by Cyrux on Ubuntu 26.04 with v0.8.30 npm install;
analysis by Hunter pinpointed Ptyxis + VTE 0.84 as the cause.
Hunter Bown
fd82f85800