- v17.0.1 (#5476) rewrote the normal buffer in place per SIGWINCH, so
the terminal's own width reflow pushed wrapped fragments into native
scrollback mid-drag and resize smoothness collapsed.
- Throwaway drag frames paint on the alternate screen again; the settle
full paint fuses the buffer exit ahead of its destructive repaint.
- Kept the #5319 fixes: deferred overlay alt-exit fusing, confirmed-only
DECRPM 2026 handling, and Warp's in-place resize path.
The non-multiplexer resize fast path borrows the alternate screen for
throwaway drag frames. Warp reports a terminal height one row different
for the alt buffer, so each alt enter/leave emits a fresh SIGWINCH that
re-enters the fast path — a self-sustaining loop that floods ED3 full
repaints with completely stable geometry (observed ~130
fullPaint(clearScrollback) frames over 15s, continuing after the drag
stopped). PI_FORCE_SYNC_OUTPUT cannot help (it is a loop, not tearing);
tmux works because the multiplexer path never toggles the alt buffer.
Route resize through the in-place repaint path (no alt-screen borrow, no
ED3 rewrap) for multiplexers and for terminals that re-report size on
alt-screen toggles, via resizeRepaintsInPlace(). Default-on for Warp,
overridable with PI_TUI_RESIZE_IN_PLACE=1|0. Tradeoff matches a
multiplexer: scrollback above the window keeps its old wrap.
Tests assert no alt-screen borrow / no ED3 across a Warp resize burst and
that the override toggles both ways; existing direct-terminal resize
tests now pin TERM_PROGRAM so they stay deterministic under Warp.
- Updated `tui-runtime-internals.md` and `tui/README.md` to describe the `requestComponentRender` API and its partial compose reuse behavior.
- Added an entry to `packages/coding-agent/CHANGELOG.md` explaining how the component-scoped render path resolves input lag caused by frequent full TUI re-compositions from animated loaders.
- Handled frame shrink by re-anchoring windowTop and chunkTo at commit boundaries.
- Reset committedRows when the frame shrank into committed content to keep history immutable.
- Treated geometryChanged like overlay when advancing chunkTo to stabilize repaint commit timing.
- Updated regressions to assert stable scrollback prefixes and no clear-home/dclear repaint bytes.
- Removed the built-in `background` (`bg`) slash command and its `handleBackgroundCommand` path from the interactive flow.
- Deleted background event subscription and shutdown handling by removing `handleBackgroundEvent` from the event, input, and interactive controllers.
- Simplified `InteractiveModeContext` by dropping background-only fields and helpers such as `isBackgrounded`, background UI context creation, and background event callbacks.
- Added tui-core-renderer.md covering yank/corruption/flash/width faults.
- Linked the new doc from runtime internals and the tui.ts header.
- Refreshed runtime-internals to match current boot and render-intent flow.
- Moved documentation files from packages/coding-agent/docs/ to root docs/ directory to flatten the documentation structure.
- Updated all internal documentation links to account for the new file locations, adjusting relative paths to maintain correct references across the monorepo.
- Updated README.md and issue template configuration to reference documentation at the new root docs/ location instead of packages/coding-agent/docs/.
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