Terminals speaking the CSI-u (kitty / fixterms) keyboard protocol -- kitty,
Ghostty, WezTerm, and terminal panes that default to it -- encode Shift+Enter
as the escape sequence "\x1b[13;2u". prompt_toolkit 3.0 has no support for
that protocol and no default mapping for the sequence, so its Vt100Parser
fails to recognise it and dumps the raw bytes ("^[[13;2u") straight into the
prompt buffer. The multiline-input work kept only Alt+Enter, so on these
terminals Shift+Enter now leaks visible escape garbage into the input.
Register "\x1b[13;2u" (absent from prompt_toolkit's default ANSI_SEQUENCES,
so setdefault() overrides nothing) and bind it to insert a newline, matching
the Alt+Enter behaviour. This is best-effort: prompt_toolkit cannot negotiate
the protocol, so we only react to a CSI-u sequence a terminal already emits;
terminals that collapse Shift+Enter into plain Enter fall back to Alt+Enter,
which stays the primary shortcut.
Add a real-PromptSession regression test asserting the sequence inserts a
newline rather than leaking raw escape bytes.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
99e04c2da2