RMUX 0.9.1

RMUX 0.9.1 is a security, compatibility, and reliability release for the 0.9 series. It strengthens access control, improves Windows terminal behavior, completes several tmux-compatible features, and makes SDK pane operations more resilient.

## Highlights

• Added visible pane scrollbars and copy-mode line-number gutters, including styling, geometry, and mouse interaction.
• Hardened server-access authorization across attaches, control clients, prompts, menus, mode trees, and delayed operations.
• Improved Windows clipboard, multiline bracketed paste, terminal input, and exclusive-action handling.
• Strengthened stable pane identity across reindexing, moves, delayed commands, and SDK operations.
• Improved daemon shutdown, process cleanup, Unix socket recovery, and special-file buffer I/O.
• Produced signed, immutable, and independently verifiable artifacts through RMUX's exact-candidate release pipeline.

## Fixed and Hardened Issues

• [#125] (https://github.com/Helvesec/rmux/issues/125) — Fixed keyboard-driven begin-selection and select-line jumping to a previously cached mouse position. Mouse coordinates are now consumed only by commands originating from the applicable mouse event.

• [#92] (https://github.com/Helvesec/rmux/issues/92) — Completed Windows multiline bracketed-paste handling across LF/CRLF input, fragmented reads, isolated leading characters, and intervening console key noise.

• [#91] (https://github.com/Helvesec/rmux/issues/91) — Further hardened OSC 52 clipboard handling by binding replies to their originating attach generation and routing queries only through eligible attached clients.

• [#94] (https://github.com/Helvesec/rmux/issues/94) — Extended stable-pane identity guarantees beyond snapshots to composite SDK operations, render streams, moves, reindexing, and cancelled reads.

## Security

• Revalidate server-access authority during attach and control registration and before delayed or interactive operations execute.
• Keep Unix socket permissions synchronized with access-control changes and socket rebinding.
• Prevent late or timed-out OSC 52 replies from satisfying later clipboard requests.
• Reject Windows batch scripts in structured argv mode, where cmd.exe cannot safely preserve arbitrary argument boundaries.

## tmux Compatibility

• Render pane scrollbars and copy-mode line-number gutters with compatible styles and mouse hit-testing.
• Implement list-windows -a across sessions.
• Improve repeated target precedence, sourced-command target resolution, linked-window mutations, lifecycle hooks, and final-window removal.
• Keep if-shell -F synchronous when combined with -b, matching tmux 3.7b behavior.
• Keep keyboard copy-mode selections anchored to the keyboard cursor when mouse mode is enabled.
• Prevent background run-shell and if-shell queues from reusing stale mouse coordinates.
• Improve get-clipboard, focus-follows-mouse, float comparisons, and linked-pane selection behavior.

## SDK and Reliability

• Pin composite pane operations to stable pane IDs across moves and reindexing.
• Preserve in-flight render updates when a pending next() call is cancelled.
• Bind guarded delayed actions to the exact client, session, window occurrence, pane, or output generation they captured.
• Make special-file buffer I/O cancellable and handle empty-writer FIFOs correctly on macOS.
• Restore private and custom Unix sockets safely at startup and after SIGUSR1.
• Join accepted daemon tasks and tracked status-job process trees during shutdown.
• Fence and reset Windows terminal input around exclusive terminal actions.

## Packaging

• [#104] (https://github.com/Helvesec/rmux/pull/104) — Added prefix-aware discovery of private helpers under lib/rmux/libexec, improving compatibility with Arch Linux and other Unix package layouts.

• Publish Linux x86_64 and arm64, macOS Intel and Apple Silicon, Windows x86_64, Debian, RPM, and Snap artifacts.

• Provide SHA256 checksums, Sigstore release authorization, and SLSA Build Level 2 provenance attestations.
• The stable tag and GitHub Release are signed and immutable.

## Upgrade Notes

RMUX 0.9.1 keeps detached RPC wire version 5 and remains wire-compatible with RMUX 0.9.0.

Restart long-running RMUX servers after upgrading so all fixes take effect:

rmux kill-server

See SECURITY.md (https://github.com/Helvesec/rmux/blob/v0.9.1/SECURITY.md#verifying-releases) for release verification instructions.

## Contributor

Thanks to @BarbUk (https://github.com/BarbUk) for the prefix-aware Unix helper discovery contributed through [#104] (https://github.com/Helvesec/rmux/pull/104).

Direct downloads, checksums, and signature material are available below.