Closes#5346.
Most terminals send the same byte sequence for `Enter` and `Shift+Enter`
by default, so the application can't tell them apart — this is a terminal
protocol limitation, not something Hermes can paper over. But terminals
that implement the Kitty keyboard protocol (Kitty / foot / WezTerm /
Ghostty by default; iTerm2 / Alacritty / VS Code terminal / Warp once the
protocol is enabled) DO emit a distinct sequence for `Shift+Enter`:
- `\x1b[13;2u` — Kitty / CSI-u, modifier=2
- `\x1b[27;2;13~` — xterm modifyOtherKeys=2
Stock prompt_toolkit doesn't have the CSI-u sequence in its
`ANSI_SEQUENCES` table at all, and it maps the modifyOtherKeys variant to
plain `Keys.ControlM` (Enter) — i.e. it strips the Shift modifier, which
is the bug users actually hit on iTerm2 and friends.
This PR adds `hermes_cli/pt_input_extras.install_shift_enter_alias()`,
called once at CLI startup from `cli.py`, which inserts/overwrites those
sequences in `ANSI_SEQUENCES` so they decode to `(Keys.Escape, Keys.ControlM)`
— the same key tuple `Alt+Enter` produces. The existing Alt+Enter newline
handler (`@kb.add('escape', 'enter')` in `cli.py`) then fires unchanged,
so there is no new keybinding to register and no behavioral change for
terminals that don't emit the distinct sequences.
Files
=====
* `hermes_cli/pt_input_extras.py` — new module hosting the helper. Lives
outside `cli.py` so it's importable in tests without dragging in the
full CLI runtime (which depends on `fire`, `rich`, etc.).
* `cli.py` — calls `install_shift_enter_alias()` once at module import.
Wrapped in try/except so prompt_toolkit version drift can't break CLI
startup.
* `tests/cli/test_cli_shift_enter_newline.py` — 6 tests:
- registration of all three byte sequences
- overwrite of stock prompt_toolkit's broken modifyOtherKeys mapping
- idempotency
- parser equivalence: CSI-u Shift+Enter == Alt+Enter
- parser equivalence: modifyOtherKeys Shift+Enter == Alt+Enter
- plain Enter remains a single key (submit), distinct from the two-key
Alt+Enter / Shift+Enter tuple
* `website/docs/user-guide/cli.md` — keybinding table updated; new
"Shift+Enter compatibility" subsection with a per-terminal status table
noting macOS Terminal / stock Windows Terminal cannot distinguish the
keystroke at the protocol level.
* `website/docs/getting-started/quickstart.md`,
`website/docs/guides/tips.md` — short mention pointing readers at the
full compatibility note in `cli.md`.
Tested
======
pytest tests/cli/test_cli_shift_enter_newline.py # 6 passed
Live-tested by triggering `\x1b[13;2u` against the running Vt100Parser
(see test). Not exercised in a real terminal end-to-end because that
requires a Kitty-protocol-capable host; the test exercises the parser
path that drives the live terminal too.
