anomalyco / anomalyco/opencode
--mini wipes scrollback and replays the whole session on every terminal resize
@simonklee is already working on this.
Since Jul 22, 2026.
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Description
Description
Resizing the terminal in --mini (tmux pane split, window drag, any SIGWINCH) makes the UI:
- wipe the screen and the terminal's saved scrollback (
ESC[2J+ESC[3J) - refetch the whole session from the server
- reprint every message from the beginning
Every resize re-scrolls the entire session. Scroll position is lost, along with any scrollback from before opencode started.
A second bug hides under it: widen the terminal while a response is streaming and the output after the resize is silently dropped (scrollback entries commit by layout row; the old row offset is invalid at the new width).
The reprint exists to re-wrap history at the new width. Only terminals that don't reflow scrollback themselves need that: plain xterm, and partially GNU screen. Everything modern reflows on its own, so by default everyone else pays the wipe-and-reprint for nothing.
Fix available: make resize replay opt-in, resume replay unchanged. #37973 (dev), #37974 (v2 port).
Reflow behavior by terminal, local measurements use a cursor-position probe (print a 150-char line, record cursor row;col via CSI 6n, resize, record again; a reflowing terminal moves the cursor to the re-wrapped position):
| Terminal | Reflows on resize? | Verified by |
|---|---|---|
| xterm (patch 378) | No: cursor frozen through both resizes (2;51→2;51, 3;31→3;31) |
measured (headless Xvfb); FAQ documents no reflow feature |
| GNU screen 4.00.03 | Partial: re-wraps the active line only | measured |
| tmux 3.6 | Yes (2;51→2;31, 3;31→2;51) |
measured; tmux#1269 |
| VTE (GNOME Terminal, xfce4-terminal) | Yes, since VTE 0.36 / GNOME 3.12 (2014) | GNOME/vte#135 |
| Konsole | Yes (default on), since 21.04 | KDE blog, bug 196998 |
| Windows conhost | Yes, "Wrap text output on resize", default on since Windows 10 | Windows Dev Blog 2014 |
| Windows Terminal | Yes | microsoft/terminal#4741 |
| alacritty | Yes, since 0.3.0 | changelog |
| kitty, ghostty, iTerm2, Terminal.app | Yes | maintainer threads; no primary source for the last two |
Plugins
none
OpenCode version
v1.18.0 (mechanism also present on the v2 branch in packages/tui/src/mini/)
Steps to reproduce
- Resume a long session:
opencode --mini -s <session>(or--continue) - Resize the terminal: split a tmux pane or drag the window
- The whole session re-scrolls past;
tmux display -p '#{history_size}'shows pane scrollback wiped to 0 and rebuilt;tmux pipe-paneshowsESC[2J+ESC[3Jemitted per resize
Screenshot and/or share link
Operating System
macOS 14 (Darwin 23.6)
Terminal
tmux 3.6 (any terminal; easiest to see under tmux)
Contributor guide
First steps
- Read the whole issue, then the project's contributing guide.
- Comment on the issue to say you are picking it up — it saves two people doing the same work.
- Fork the repository and make your change on a branch.
- Open a pull request that references the issue number.
Assessment
This issue has not been assessed yet.