[Ipriyankrajai]

Summary

• When opening a terminal via preset (Ctrl+1), ink-based TUI apps like Claude Code rendered at ~1/3 width because the PTY was spawned with stale container dimensions
• After a successful createOrAttach, schedules a requestAnimationFrame to re-fit xterm and send corrected dimensions to the PTY via SIGWINCH
• The resize is only sent if dimensions actually changed, making it a no-op when the initial size was already correct

Screen.Recording.2026-04-04.at.12.51.04.AM.mov

Root Cause

fitAddon.fit() runs synchronously in createTerminalInstance before the container has its final layout. The ResizeObserver catches the correct size but is debounced at 150ms. Most CLIs handle the late SIGWINCH fine, but ink-based TUI apps (Claude Code) commit to the initial width during their first render cycle and don't fully reflow.

Test plan

• Open a Claude Code preset via Ctrl+1 — verify it renders at full terminal width immediately
• Open other CLI presets (Codex, OpenCode) — verify no regression
• Resize the window while a terminal is active — verify resize still works correctly
• Split panes and open presets — verify dimensions are correct in all panes
• Reattach to an existing session — verify no double resize or flicker

Summary by CodeRabbit

• Bug Fixes
  • Terminal sizing now waits for the interface layout to settle before finalizing dimensions, ensuring new or attached terminals render at the correct columns/rows and preventing misaligned or incorrectly sized terminal content.

[coderabbitai]

📝 Walkthrough

Walkthrough

Schedules a post-attachment requestAnimationFrame to run fitAddon.fit() after layout settles, verifies attachment is still active, compares pre- and post-fit xterm cols/rows, and calls resizeRef.current with updated dimensions if they changed.

Changes

Cohort / File(s)	Summary
Terminal Lifecycle Enhancement apps/desktop/src/renderer/screens/main/components/WorkspaceView/ContentView/TabsContent/Terminal/hooks/useTerminalLifecycle.ts	On successful attach, enqueues a requestAnimationFrame callback that captures pre-fit xterm cols/rows, performs fitAddon.fit(), re-checks dimensions, and invokes resizeRef.current(paneId, cols, rows) when post-fit sizes differ to sync PTY sizing.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~12 minutes

Poem

🐰 I hopped in quiet, timing on my mind,
A frame I waited for, then gentle fit I find.
I checked the rows and cols both before and after,
If sizes changed, I nudged the PTY with laughter.
Hooray — the terminal breathes, precise and kind!

🚥 Pre-merge checks | ✅ 2 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (2 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly summarizes the main change: fixing terminal dimensions being sent to TUI apps after attach, which directly addresses the root cause of the issue described in the PR.
Description check	✅ Passed	The pull request description includes all required sections from the template: Summary, Related Issues context, Type of Change (implicitly a bug fix), detailed Testing plan with checkboxes, and Additional Notes explaining the root cause and implementation.

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✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

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[greptile-apps]

Greptile Summary

This PR fixes a timing bug where ink-based TUI apps (e.g. Claude Code) rendered at the wrong terminal width after being opened via a preset shortcut. The root cause is that fitAddon.fit() runs synchronously during createTerminalInstance before the container has reached its final layout dimensions, while the 150ms-debounced ResizeObserver fires too late for ink's first render cycle.

The fix schedules a requestAnimationFrame inside the onSuccess callback of createOrAttach, re-running fitAddon.fit() once the browser has completed layout and sending SIGWINCH only when dimensions actually changed (making it a no-op when the initial size was already correct).

Key observations:

• The isAttachActive() guard correctly prevents stale callbacks from firing after unmount or superseding attaches.
• The local fitAddon closure variable is used (consistent with the rest of the lifecycle effect), not fitAddonRef.
• No cancelAnimationFrame tracking is added for this new rAF, but this is consistent with scheduleScrollToBottom and is safe because isAttachActive() acts as the guard.
• One P2 note: the rAF is scheduled unconditionally before the cold-restore early-return paths, meaning it fires and may dispatch a resize mutation even for sessions showing read-only restored scrollback. This is almost certainly a silent no-op in practice, but is semantically unexpected.
• The restartTerminalSession path (non-mount restarts) does not get this fix; that appears intentional based on the PR scope.

Confidence Score: 4/5

• Safe to merge; the fix is well-guarded and targeted — one minor P2 cleanup remains around cold-restore interaction.
• The change is small (20 lines), correctly guarded against stale-attach and unmount races, and addresses a real and well-understood layout-timing bug. The only non-blocking concern is that the rAF fires unconditionally before cold-restore early-return paths, which may dispatch a spurious (likely no-op) resize mutation to a session with no active PTY. No logic or security issues found.
• No files require special attention beyond the single changed hook.

Important Files Changed

Filename	Overview
apps/desktop/src/renderer/screens/main/components/WorkspaceView/ContentView/TabsContent/Terminal/hooks/useTerminalLifecycle.ts	Adds a requestAnimationFrame after successful createOrAttach to re-fit xterm and send corrected PTY dimensions via SIGWINCH; fix is well-guarded with isAttachActive() but the rAF fires even for cold-restore early-return paths, potentially sending a spurious resize to a session with no active PTY.

Sequence Diagram

sequenceDiagram
    participant React as React Mount
    participant TI as createTerminalInstance
    participant FA as fitAddon
    participant RO as ResizeObserver (150ms debounce)
    participant CA as createOrAttach (IPC)
    participant RAF as requestAnimationFrame (new)
    participant PTY as PTY / SIGWINCH

    React->>TI: mount effect
    TI->>FA: fitAddon.fit() [stale layout]
    TI->>CA: createOrAttach(cols=stale, rows=stale)
    Note over RO: Container reaches final layout
    RO-->>RO: debounce timer starts (150ms)
    CA-->>React: onSuccess
    React->>RAF: schedule rAF
    RAF->>FA: fitAddon.fit() [correct layout]
    FA-->>RAF: xterm.cols/rows updated
    RAF->>PTY: resizeRef (SIGWINCH) if dims changed
    Note over PTY: TUI app (ink/Claude Code) gets correct width
    RO-->>PTY: resizeRef (150ms later, same dims — no-op for TUI)

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_{Reviews (1): Last reviewed commit: "fix(desktop): send correct terminal dime..." | Re-trigger Greptile}

[greptile-apps]

rAF fires for cold-restore sessions too

The requestAnimationFrame is scheduled unconditionally before the cold-restore early-return paths (lines ~579–607). When storedColdRestore?.isRestored or result.isColdRestore is true, the function returns early but the queued rAF still fires — calling fitAddon.fit() and potentially dispatching resizeRef.current(...) against a PTY that is showing read-only restored scrollback and may have no active process behind it.

In most implementations resizeRef will silently no-op if there is no live PTY session, so this is unlikely to cause visible breakage. But it is semantically surprising and could produce a spurious resize mutation. Consider guarding the rAF so it is only scheduled for live (non-cold-restore) sessions, or at least documenting why it is safe to resize during a cold restore.

Suggested change

	requestAnimationFrame(() => {
	if (!isAttachActive()) return;
	const prevCols = xterm.cols;
	const prevRows = xterm.rows;
	fitAddon.fit();
	if (xterm.cols !== prevCols || xterm.rows !== prevRows) {
	resizeRef.current({
	paneId,
	cols: xterm.cols,
	rows: xterm.rows,
	});
	}
	});
	// After attach, the container may have finished layout
	// at its final size while the PTY was spawned with stale
	// dimensions (from before the container was fully laid out).
	// Re-fit and send correct dimensions so TUI apps (e.g.
	// Claude Code / ink) receive SIGWINCH before their initial
	// render commits to the wrong width.
	//
	// Only schedule for live sessions; cold-restore paths below
	// return early and have no active PTY to receive SIGWINCH.
	const isColdRestoreSession =
	coldRestoreState.get(paneId)?.isRestored ||
	result.isColdRestore;
	if (!isColdRestoreSession) {
	requestAnimationFrame(() => {
	if (!isAttachActive()) return;
	const prevCols = xterm.cols;
	const prevRows = xterm.rows;
	fitAddon.fit();
	if (xterm.cols !== prevCols || xterm.rows !== prevRows) {
	resizeRef.current({
	paneId,
	cols: xterm.cols,
	rows: xterm.rows,
	});
	}
	});
	}

[cubic-dev-ai]

1 issue found across 1 file

Prompt for AI agents (unresolved issues)

Check if these issues are valid — if so, understand the root cause of each and fix them. If appropriate, use sub-agents to investigate and fix each issue separately.


<file name="apps/desktop/src/renderer/screens/main/components/WorkspaceView/ContentView/TabsContent/Terminal/hooks/useTerminalLifecycle.ts">

<violation number="1" location="apps/desktop/src/renderer/screens/main/components/WorkspaceView/ContentView/TabsContent/Terminal/hooks/useTerminalLifecycle.ts:565">
P2: The `requestAnimationFrame` resize is scheduled unconditionally before the cold-restore early-return paths below. For cold-restore sessions (read-only scrollback, no active PTY process), the rAF still fires and may call `fitAddon.fit()` + `resizeRef.current(...)` against a session with no live process. Guard this so it only runs for live sessions, e.g. by checking `coldRestoreState.get(paneId)?.isRestored` before scheduling.</violation>
</file>

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