fix(terminal): place cursor correctly after restart for persistent TUIs#1324
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fix(terminal): place cursor correctly after restart for persistent TUIs#1324
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SerializeAddon emits a relative cursor-move tail (\x1b[NA\x1b[MD)
computed from the last content cell it serialized to the terminal's real
cursor. That math drifts when a TUI drew rows below the cursor (border,
status lines) and then parked the cursor back on an input prompt above
— on replay the cursor lands one row below the prompt.
Append an authoritative absolute CSI row;col H after SerializeAddon
output at both capture sites (renderer captureBuffers and daemon
HeadlessEmulator.getSnapshot) using the terminal's live
buffer.active.cursorY/cursorX. The absolute positioner is the last
cursor-move seen on replay, overriding SerializeAddon's drifty relative
tail.
Also remove two cooperating bugs in restoreScrollbackBuffers and
document the contract:
1. Alt-screen trim (slice(0, lastIndexOf('\x1b[?1049h'))) discarded
not only alt-buffer content but the cursor-position tail, mode
bits, and scroll region — fueling the "cursor lands below input
box" bug for Claude Code, vim, lazygit.
2. Unconditional trailing \r\n append for PROMPT_EOL_MARK pushed the
cursor one extra row down on top of the alt-trim drift.
The reattach path in pty-connection.ts is authoritative when it has
data; restoreScrollbackBuffers is the pre-paint and must replay the
serialized buffer verbatim + POST_REPLAY_MODE_RESET only.
Co-authored-by: Orca <help@stably.ai>
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Summary
CSI row;col Hcursor positioner afterSerializeAddonoutput in both capture sites (renderercaptureBuffers, daemonHeadlessEmulator.getSnapshot). SerializeAddon's relative cursor-move tail drifts when a TUI drew rows below the cursor (border/status lines) and parked the cursor back on an input prompt above — on replay the cursor lands one row below the prompt.\r\nappend inrestoreScrollbackBuffers(both contributed to the drift) and document the pre-paint/authoritative-reattach contract on the function.docs/design/fix-persistent-terminal-cursor-after-restart.mdcaptures the two restore paths, root cause, and chosen fix.Test plan
pnpm test—src/main/daemon/headless-emulator.test.ts(23 pass, +2 new) andsrc/renderer/src/components/terminal-pane/layout-serialization.test.ts(26 pass, +3 new)shell-readyfailures unchanged from baseline)pnpm tsc --noEmitcleanvim/lazygitin alt-screen — cursor lands where it wasMade with Orca 🐋