Leaked OSC 11 background-color reply appears in the TUI input line at launch (Orca terminal, macOS)

Leaked OSC 11 background-color reply appears in the TUI input line at launch (Orca terminal, macOS)

Environment

• jcode: v0.76.0 (bbef1f6a8)
• OS: macOS 15, Apple Silicon
• Terminal: Orca.app's built-in Electron terminal (Orca 1.4.183)
• TERM as seen by jcode: Orca-managed PTY inside the app

What happens

When launching jcode in Orca's terminal, the tail of the terminal's OSC 11
response is parsed as keystrokes and shows up in the input line:

11;rgb:3030/3434/4646

3030/3434/4646 is #303446, Orca's terminal background. It appears right
after whatever I type first, so the first prompt of every session starts with
this junk in the composer (and can be accidentally submitted).

Repro

1. Launch jcode in Orca's terminal pane.
2. As soon as the TUI is up, the input line contains 11;rgb:3030/3434/4646 (or
   it gets prepended to the first thing typed).
3. Reproduces on most launches in Orca; I have not seen it in other terminals.

Analysis

At startup jcode queries the terminal background color for theme detection
(ESC ] 11 ; ?, the jcode-theme-detect path; the binary also contains
osc11-silent-terminals caching and a
"Skipping terminal background query for a terminal without OSC query support"
message). The terminal replies ESC ] 11 ; rgb:.... ST.

In Orca's Electron terminal the reply arrives after jcode has already given up
waiting for it and switched into raw TUI input mode, so the leftover bytes
(the part after ESC ]) are fed to the key handler and typed into the composer.

Two things stand out:

• The late-reply path doesn't seem to be consumed/discarded anywhere, so a slow
  answering terminal leaks visible text. A race-free approach would be to keep
  a small window where an unsolicited-looking OSC 11 reply is still swallowed,
  or to filter ESC ] 11 ; rgb:... (plus both ST/BEL terminators) in the input
  parser after the query window closes.
• The osc11-silent-terminals cache only helps for terminals that never answer.
  Orca does answer, just after the timeout, so the cache never engages and
  the leak repeats every launch.

Same class of issue has hit other multiplexers/terminal wrappers (e.g. replies
to OSC 11 echoing as literal text after the requester stopped reading).

Expected

The reply to jcode's own startup query should never surface as user input,
regardless of how late the terminal answers.

Workaround

None found; no flag to skip the background query was visible in jcode --help.

Made with Orca 🐋

Start with the jcode-theme-detect path, the osc11-silent-terminals cache, and the input parser described in the report. Reproduce the launch in Orca, trace the late OSC 11 response after the query timeout, and verify that both ST and BEL-terminated replies no longer appear as user input.