Fixed session picker line truncationPublic

Issue 764: Session picker crashes on narrow terminals (< 78 columns). State: open. No comments. Linked PR: #731.

Bug analysis

• Code path: /resume uses packages/coding-agent/src/cli/session-picker.ts which instantiates SessionSelectorComponent. That renders SessionSelectorHeader.render() and returns two lines. The second line is the hint string. packages/tui/src/tui.ts checks each rendered line width and throws if any line exceeds terminal.columns.
• Actual root cause: SessionSelectorHeader.render() in packages/coding-agent/src/modes/interactive/components/session-selector.ts returns the hint line without truncation. The hint text is 78 visible columns. On terminals narrower than 78, visibleWidth() detects overflow and TUI.doRender() throws the error.

Proposed fix

• Truncate the hint line to the current width. This keeps the line within the terminal width and avoids TUI aborts.
• Example approach in SessionSelectorHeader.render():
  • Keep a hintText constant.
  • Use truncateToWidth() for the hint line, with a muted ellipsis so styling stays consistent.
  • Suggested shape:
    • const hintText = 'Tab: scope · Ctrl+R: sort · re:<pattern> for regex · "phrase" for exact phrase';
    • const hint = truncateToWidth(theme.fg("muted", hintText), width, theme.fg("muted", "…"));

Affected files

• packages/coding-agent/src/modes/interactive/components/session-selector.ts
  Update the hint line rendering to truncate to width.

Optional regression test

• Add a small unit test that calls SessionSelectorHeader.render(56) and asserts visibleWidth(line) <= 56 for all lines. There is no existing UI render test harness, so this would be new work.

Using a Text component that wraps would avoid the crash, but it changes layout. The header currently returns two lines. Wrapping the hint would add more lines as terminal width shrinks, which changes the header height and pushes the session list down. That might be acceptable, but it is a behavioral change.

If you want wrapping, you would need to refactor the header from a plain component that returns two lines into a container with a Text child, or call wrapTextWithAnsi directly. That also means adjusting spacing assumptions around the header and the dynamic border. Truncation keeps the layout stable and avoids extra vertical growth.

That output means your terminal is wide enough to avoid the crash, but still narrow enough that the first line auto-wraps and visually runs into the hint line. The header returns two separate lines. The terminal wraps the first line, so the second line starts mid wrap and looks concatenated.

The crash only happens when a single rendered line exceeds the TUI width check. If your terminal width is at least 78 columns, it will not throw.

If you want, tell me your terminal width in columns and I can confirm which line is wrapping and whether truncation or wrapping is the better fix for your setup.

If it does not crash at 30 columns, the TUI probably thinks the terminal is wider than it actually is. In that case the line width check passes, but your terminal wraps because the real width is smaller.

This usually happens when the terminal or tmux is not reporting resize events correctly. To confirm, check what the process thinks the width is inside the same session:

tput colsstty sizenode -e 'console.log(process.stdout.columns)'

If those still show a larger width, the crash does not trigger. The report in #764 uses tmux with a fixed width so the TUI sees the correct value and it crashes.

Tell me the values you see and whether you are inside tmux, and I can map it to a fix or a repro that matches your setup.

It is not the same rendering path because the width that the TUI uses is whatever process.stdout.columns reports at render time. Two cases:

1. Resize first, then run /resume
   The initial render runs with the smaller columns value. The hint line is longer than columns, so TUI.doRender() throws.

2. Run /resume, then resize
   The first render runs with the old columns value, so it does not crash. After resizing, the TUI only re-renders when it gets a resize event. In your setup the resize event does not update the columns value, so the TUI keeps using the old width and does not crash. This matches your tput cols output of 80 even after resizing.

So the crash depends on when the width becomes smaller from the TUI’s point of view, not the terminal’s visual size. If process.stdout.columns does not change, the check never triggers.

If you want, I can show you a repro that forces columns to update in tmux so the crash happens every time.

Summary:

• Truncated the session picker hint line to terminal width in packages/coding-agent/src/modes/interactive/components/session-selector.ts.
• Ran checks and pushed after rebasing.

Tests:

• npm run check

Issue:

• gh issue close 764 reported the issue is already closed.

The crash log shows a different line overflowing now:

• Terminal width: 47
• Line 73 width: 55
• Line 73 text: No sessions in current folder. Press Tab to view all.

So your hint truncation worked. The new crash is from the empty state message in SessionList.render() when there are no sessions. That line is not truncated.

Location: packages/coding-agent/src/modes/interactive/components/session-selector.ts

Current code:

lines.push(theme.fg("muted", "  No sessions in current folder. Press Tab to view all."));

Fix: Wrap this with truncateToWidth(..., width, "…"), same as other lines.

If you want me to implement, commit, and push this follow‑up, say the word.

Summary:

• Truncated the “No sessions in current folder” empty state line to terminal width in packages/coding-agent/src/modes/interactive/components/session-selector.ts.
• Ran checks and pushed.

Tests:

• npm run check

Looking at the file (which has my fixes), there's one more line that needs truncation:

Line 166: " No sessions found" (the "All" scope empty state)

This is 18 chars, so it would only overflow on very narrow terminals, but for consistency and safety it should be truncated too.

All other lines are either:

• Already truncated
• Computed to fit width (header line 1 with spacing)
• Empty strings
• From Input component (handles its own width)

Want me to add truncation to that last line as well?

Done. All session picker lines are now truncated:

1. Hint line (already fixed)
2. "No sessions in current folder..." (already fixed)
3. "No sessions found" (just fixed)