Vterm Stage 3 — the final vterm stage. A semantic frontend can now host a
terminal: the daemon ships complete validated cell grids, and pmacs-gpu
renders them with fixed-cell geometry, its own input path, and no document
projection at all.
Protocol v19 appends three variants after their enums' final v18 members:
InstanceMessage::TerminalFrame (daemon-gated), and FrontendEvent::
TerminalResize / TerminalPointer (frontend-gated). It is the first bump to
gate in both directions, so criterion 28 pins each filter independently and
byte pins on StatuslineSegments and MenuPointer guard the placements.
pmacs-protocol gains src/terminal.rs: the shared row/column/visible-cell/
grapheme/metadata bounds, TerminalProcessState, TerminalSelectionSpan, and
TerminalFrame::validate — the ONE structural policy the daemon runs before
emission and the frontend runs after decode. src/terminal/* re-exports them
so no duplicate type exists, and unicode-width becomes a workspace dependency
so the screen and the validator measure glyph columns with one table. A new
8 MiB aggregate glyph bound keeps the largest legal frame (measured:
13,437,863 bytes) under the unchanged 16 MiB transport cap rather than
widening every connection's allocation ceiling.
The semantic producer suppresses the whole document family for a terminal
buffer while keeping the status band, theme, font, statusline, menu, and
minibuffer, and compares the complete ordered payload rather than
screen_generation — scroll, selection, and process state all change without
advancing it.
Two things the framing did not spell out, both found by the real-daemon
acceptance:
The Viewport gate keys on the authenticated source's ACTIVE buffer, not the
buffer the message names. Viewport also aligns the window to what it
declares, so a stale document viewport in flight when a command opened a
terminal dragged the frontend straight back off it: the window oscillated,
every terminal declaration was refused, and no frame ever arrived, with
nothing logged anywhere.
The producer clears terminal mode on every exit path. The daemon uses that
flag to suppress CursorByte and the presence sweep, so an early return that
left it set kept both suppressed after the frontend returned to a document.
pmacs-gpu/src/terminal.rs is a pure cell-space paint planner, unit-testable
without a GPU. The renderer builds one shaped buffer per text run, so a wide
or cluster glyph's advance can never choose the next column's origin.
Criterion 37 needed a seam rather than a fixture: pmacs-gpu depends only on
pmacs-protocol, so attach::connect's reader sink was generalized and a
--headless-probe mode added. The acceptance drives a real daemon, a real
/bin/sh child, the real attach client, and real composited pixels in one
path — which is how both defects above were found.
Gates: fmt; strict workspace clippy; 1,757 default + 1,933 CRDT library
tests; vterm Stage 1 9/10, Stage 2 4/4, Stage 3 4/5 acceptance
(default/CRDT); statusline 7/8; M4 120; required GPU 127; workspace sweep
2,919 across 83 suites; diff check clean.
Levi Neuwirth
bdf2b6e4b4