Two pieces:
**#1073 fix.** When a paste burst is currently being assembled, or when
the burst's Enter-suppression window is still open after a flush, the
trailing newline of the paste was firing `submit_input()` and the
in-flight burst buffer was getting destroyed by `clear_after_explicit_paste()`.
The PasteBurst module already exposed `newline_should_insert_instead_of_submit`
and `append_newline_if_active` for exactly this case, but no caller had
been wired up. Added `App::handle_composer_enter`, which checks the
suppression state and either appends `\n` to the burst buffer or inserts
it directly into the composer text — no submit. The `KeyCode::Enter`
arm in the composer event loop now dispatches through that helper.
Reproduces the Windows/PowerShell symptom from the report:
multi-line paste ending with `\n` no longer auto-submits AND the text
no longer leaks into the now-empty composer.
Four unit tests cover: active-burst Enter, post-flush window Enter,
normal Enter outside the window, and Enter with paste-burst detection
disabled (suppression must be off).
**PTY QA harness.** New `crates/tui/tests/support/qa_harness/` wraps
`portable-pty` (already a runtime dep) and `vt100` (new dev-dep) into
a small surface for scenarios that need a real PTY: spawn a binary,
send keys/paste/resize, parse the ANSI stream into a frame, assert
on visible text + filesystem state. The harness seals `$HOME` so
scenarios cannot read the developer's real `~/.deepseek/` and points
the base URL at 127.0.0.1:1 so no live request escapes. README under
`support/qa_harness/README.md` documents how to add a scenario.
Initial scenarios in `crates/tui/tests/qa_pty.rs`: smoke boot,
keystroke round-trip, and bracketed/unbracketed paste-with-trailing-
newline regression guards for #1073. The unbracketed scenario does
not deterministically reproduce the bug on macOS (single-syscall
PTY writes keep the burst continuously active), but the unit tests
above cover the path conclusively; the PTY test stands as a
regression guard for the visible-text invariant.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Hunter Bown
4e285595b0