[StiensWout]

Summary

• Queue a server-side flush sentinel so resize acknowledgements follow all previously queued PTY output.
• Return the covered attach-stream sequence in each resize acknowledgement, and wait for that exact sequence before applying Ghostty dimensions.
• Gate Ghostty grid changes on accepted PTY dimensions with single-flight desired-size retries and safe disposal.
• Hold initial terminal history/output until the first accepted grid so old-width bytes cannot be replayed as duplicate lines during resize.
• Prefill the opaque terminal canvas with the theme background before font/WASM initialization.

Validation

• Server ordering tests: 3 passed.
• Focused web terminal tests: 46 passed.
• Contract tests: 23 passed; client-runtime terminal state tests: 6 passed.
• Server, contracts, client-runtime, and web typechecks: passed.
• Focused lint for touched terminal files: passed.

Actual T3 preview

The GIF below is captured from the real T3 Code UI and terminal drawer on this branch while resizing wide → narrow → wide. It contains no synthetic frame or added border:

This intentionally does not include terminal open/close reconciliation or Ctrl+W handling.

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Note

Medium Risk
Resize RPCs now block until output drains, and synchronous resize-from-listener paths are sensitive; changes touch core terminal I/O ordering across server and web renderer.

Overview
Terminal resize is now ordered end-to-end so PTY width and Ghostty grid stay aligned during drawer resize and streaming output.

Contracts & client state: resize returns TerminalResizeResult with an attach-stream sequence instead of void. Terminal session/buffer state tracks sequence alongside version so the UI knows which output events have been applied.

Server (TerminalManager): Before acknowledging a resize, the manager queues a flush sentinel on the PTY output drain, publishes all prior queued output, and returns the covered eventSequence. Flush sentinels are released on queue disposal (including exit) to avoid hangs; tests cover ordering, listener-triggered resize deadlock, and exit during a blocked drain.

Web UI: TerminalWriteBarrier waits until React has applied output up to the resize acknowledgement’s sequence before and after runTerminalResize. GhosttyTerminalSurface starts at a 1×1 grid, buffers initial history/output until the first accepted PTY resize, uses async onResize with single-flight requests and retries, and prefills the opaque canvas with the theme background during async init.

^{Reviewed by Cursor Bugbot for commit 55f52f5. Bugbot is set up for automated code reviews on this repo. Configure here.}

Note

Keep PTY and Ghostty resize ordering in lockstep by sequencing resize acknowledgements

• Introduces TerminalResizeResult (with a sequence field) as the return type for resize RPCs, replacing void, so callers know which output event the PTY had processed at acknowledgement time.
• The server's TerminalManager.resize now queues a flush sentinel and waits for all in-flight output to be published before returning, ensuring the sequence number reflects output order.
• The Ghostty surface (GhosttyTerminalSurface) buffers writes until the first resize is acknowledged, applies grid changes only on accepted PTY resizes, and retries on unchanged-dimension rejection to avoid jitter.
• A new client-side TerminalWriteBarrier in ThreadTerminalDrawer gates grid changes until the corresponding output sequence has been applied to the terminal buffer.
• Sequence numbers are now tracked end-to-end in TerminalSessionState and TerminalBufferState via nextTerminalSequence.
• Risk: resize no longer returns immediately — it suspends until queued output drains, which could block callers if the drain stalls (guarded by deadlock detection for synchronous resize-from-listener patterns).

^{Macroscope summarized 55f52f5.}

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[macroscopeapp]

Approvability

Verdict: Needs human review

This PR fundamentally changes terminal resize synchronization between PTY and Ghostty, introducing new coordination mechanisms (flush sentinels, write barriers, acknowledgement-based grid sizing) across both server and client. While the tests are comprehensive, the significant runtime behavior changes warrant human review.

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[cursor]

Cursor Bugbot has reviewed your changes using high effort and found 1 potential issue.

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^{Reviewed by Cursor Bugbot for commit c425f1d894604c039c0cc2372ec2346b1b8776c6. Configure here.}