Problem:
Applications running inside :terminal that use DEC private mode 2026
(synchronized output) to batch screen updates get garbled rendering.
Neovim's embedded libvterm does not handle mode 2026, so the
synchronization sequences are ignored and intermediate screen states
leak through as visual corruption.
Solution:
Add mode 2026 support to libvterm's state machine and wire it through
to terminal.c. When an application enables mode 2026, invalidation of
the terminal buffer is deferred until the application disables it,
causing all accumulated screen updates to flush as a single
atomic refresh.
* fix(terminal): harden sync output redraw gating
Problem:
The initial mode 2026 implementation gated invalidate_terminal()
but missed three other redraw paths: term_sb_push/term_sb_pop
bypassed the gate by directly adding to invalidated_terminals,
refresh_timer_cb could fire mid-sync flushing partial state, and
the 10ms timer delay after sync-end left a window for stale
repaints.
Solution:
- Gate term_sb_push/term_sb_pop during synchronized output
- Skip syncing terminals in refresh_timer_cb
- On sync end, schedule a zero-delay full-screen refresh via
sync_flush_pending flag in terminal_receive()
- Add news.txt entry for mode 2026 support
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
* test(terminal): add vterm unit tests for mode 2026
Add unit-level tests for synchronized output (mode 2026) to
vterm_spec.lua, covering settermprop callbacks and DECRQM
query/response.
Suggested-by: justinmk
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
* fix(terminal): address review feedback for mode 2026
- Use multiqueue_put(main_loop.events) instead of restarting the
global refresh timer on sync end, to avoid affecting other
invalidated terminals.
- Add screen:expect_unchanged() to verify screen doesn't update
during sync mode.
- Merge buffer-lines test into existing test.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Problem:
libvterm doesn't support parsing the dim and overline attributes, so when a program running in the embedded terminal emits one of these escape codes, we ignore it and don't surface it to the outer terminal.
Solution: tweak libvterm to add support for both attributes.
Problem:
Recombining composing chars in terminal doesn't work at right edge.
Solution:
Check for the case where printing the previous char didn't advance the
cursor. Reset at_phantom when returning to combine_pos.
Problem:
Terminals should respond with the terminator (either BEL or ST) used in
the query so that clients can reliably parse the responses. The
`TermRequest` autocmd used to handle background color requests in the
terminal does not have access to the original sequence terminator, so it
always uses BEL. #37018
Solution:
Update vterm parsing to include the terminator type, then forward this
data into the emitted `TermRequest` events for OSC/DCS/APC sequences.
Update the foreground/background `TermRequest` callback to use the same
terminator as the original request.
Details:
I didn't add the terminator to the `TermResponse` event. However, I
assume the `TermResponse` event doesn't care about the terminator
because the sequence is already parsed. I also didn't update any of the
functions in `src/nvim/vterm/state.c` that write out responses. It
looked like those all pretty much used ST, and it would be a much larger
set of changes. In that same file, there's also logic for 8 bit ST
sequences, but from what I can tell, 8 bit doesn't really work (see `:h
xterm-8bit`), so I didn't use the 8 bit ST at all.
These are not needed after #35129 but making uncrustify still play nice
with them was a bit tricky.
Unfortunately `uncrustify --update-config-with-doc` breaks strings
with backslashes. This issue has been reported upstream,
and in the meanwhile auto-update on every single run has been disabled.
Many terminals now include support for OSC 52 in their Primary Device
Attributes (DA1) response. This is preferable to using XTGETTCAP because
DA1 is _much_ more broadly supported.
Problem:
Currently undefined behavior can occur when `string_fragment()` is
called with `OSC_COMMAND`. This is because when the state changes to
`OSC_COMMAND`, `string_initial` is set to true. Then in some cases,
directly after this `string_initial` will be set back to false before
the on_osc callback is called, this leads to `term_settermprop()` never
initializing the title.
Solution:
In all of the no-op cases in `string_fragment()` currently, we continue
to the end of the function where `vt->parser.string_initial` is set to
false. This change returns in the no-op cases instead since in these
cases the string has not yet been terminated and sent to the callback.
Note:
This change also adds a test with a byte sequence from the file
in #34028 that caused nvim to crash. This byte sequences is the shortest
sequence I could trim down from that file that still would trigger the
crash. There are also two other tests I added which validate that
setting the title with OSC-0 and OSC-2 still works.
Fixes: #34028
This commit adds basic support for the kitty keyboard protocol to
Neovim's builtin terminal. For now only the first mode ("Disambiguate
escape codes") is supported.
