Only a visible-frame capture positions its rows absolutely, so only that frame
can be damaged by a terminal of the wrong size. A `full=1` body is linear
scrollback closed by a relative cursor move, which is relative precisely so the
browser's row count need not match the pane's, and a `history` body is the byte
stream, which carries no row alignment to protect. The geometry comparison ran
on all three, so it fired most often on the one response it cannot help:
`_fullHistoryLoaded` is empty on the first select of every non-shell session per
page, and a session whose pane a desktop tab holds too tall to ever fit then
paid a second whole-scrollback capture, reset and replay on every page load and
every first tab switch.
`framePositionsRowsAbsolutely` gates both the captured-geometry comparison and
`sizeMovedUnderLoad`. A size that moved under a byte-stream or scrollback replay
is healed by xterm's own reflow plus the SIGWINCH the trailing `sendResize`
already sends.
A pane WIDER than the terminal damages the same frame a second way, so
`captureCols` is now compared rather than only logged. `formatPaneSnapshot`
paints each row out to the pane's own width, so a narrower browser wraps every
painted row, and the wrap on the last one scrolls the whole frame up by a row.
The terminal response no longer falls back to `session.ptyCols`/`ptyRows` when
the capture reported no geometry. The cursor query is what produces the absolute
addressing in the first place, so a capture that lost it returned a raw frame
that was never positioned, and a byte-history response was never positioned
either. Naming the session's own PTY size there described a frame that does not
exist and invited a repair for damage that is not present. `_ptyCols` is also
written only by `resize()` while the PTY is spawned at the size queried from
tmux, so it can be wrong on its own terms. Both fields are now absent instead,
and the `Session` getters added for that fallback go with it.
Two browser cases cover the new behaviour and each fails without its fix: a
`mux-full-history` response with both dimensions mismatched asserts one fetch
(two without the gate), and a `mux-visible` response wider than the terminal
but short enough to fit asserts two (one without the width comparison).
Corrects a claim in the comment above `capturedGeometry` in tmux-manager.ts.
Both replay paths do not address rows absolutely; the full-history one ends in a
relative move, which is the whole reason the gate is right.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
A visible-frame capture repaints each row at an absolute position, counting up
to the pane's height. A terminal shorter than that clamps every address past its
own height onto its last line. The overflow rows then overwrite one another, and
the rows underneath are lost. Replaying a real 50-row capture into a 30-row
terminal rendered 28 lines of a 45-line command and drew the frame twice.
Nothing in the response said what height the frame was built for, so the client
could not detect this. A capture now reports the geometry it was really taken at
through `capturedGeometry` on `PaneCaptureOptions`, and the terminal response
carries it as `captureCols` and `captureRows`. When the captured pane is taller
than the terminal, or the size that produced the capture did not survive the
load, `selectSession` replays once at the size that stuck. `resizeRetry` caps
that at one attempt, so two competing fits cannot trade replays forever.
The retry re-arms the full-history flag only when the pass that ran had consumed
it. A tab switch takes the bounded tail, so its retry takes the tail too:
clearing the flag unconditionally would upgrade that switch into a fresh
scrollback capture the user never asked for, which the route's own comments put
at tens of megabytes.
What this repairs is a capture that won a race against the resize meant to
precede it. It does not repair a capture whose pane was too tall because
`Session.resize` declined the resize outright, which it does for a small
viewport while a desktop viewport's size claim is live. The retry re-sends the
same declined resize and captures the same pane, and `resizeRetry` then stops
it. Repairing that means changing who owns the pane size, which is a policy
question this does not touch. The reported geometry still helps there, because
the client can see the mismatch at all rather than being blind to it.
Follows #395, #396 and #397, which fixed the other ways the replayed frame and
the terminal could disagree.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
