Keep set-buffer text exact and read it from stdin

[teamleaderleo]

Summary

cmux set-buffer trimmed whitespace and newlines from its text, so a buffer could never end in a newline or keep leading indentation, and it had no way to take piped input. Moving output from one pane to another meant copying it through the macOS clipboard.

set-buffer now stores the text exactly as given, like tmux, and reads stdin when there is no text argument or the argument is a lone -. With a terminal on stdin and no text it still fails with "set-buffer requires text" instead of waiting for EOF.

cmux read-screen --surface surface:1 --lines 40 | cmux set-buffer --name out
cmux paste-buffer --name out --surface surface:2

Whitespace-only text is now accepted (tmux accepts it too); only empty text is rejected. paste-buffer itself is unchanged.

Testing

• cmuxCLITests/CLITmuxCompatBufferContentTests.swift runs the bundled CLI against a scratch HOME and checks the stored buffer for: piped stdin with indentation and a trailing blank line, -, an argument with leading spaces and a trailing newline, and empty stdin (fails, nothing written).
• Commit d72fcfa adds the tests alone; three of the four fail against main's behavior (the empty-stdin guard passes on both). Commit f2d114f is the fix.
• Local: scripts/verify-local.py project, test-wiring, localization and Swift syntax checks passed. I did not build or run the tests locally; they run in CI.
• Localization: one new error string (cli.setBuffer.error.invalidUTF8), translated for all nine macOS locales; localization_catalog.py check reports 0 parity errors. The changed set-buffer help text is one of the existing unlocalized tmux-compat help blocks.

🤖 Generated with Claude Code

---

^{Need help on this PR? Tag @codesmith-bot with what you need. Autofix is disabled.}

---

Summary by cubic

set-buffer now stores text exactly as given, like tmux, instead of trimming whitespace and newlines, and reads from stdin when no text argument (or -) is passed.

• Piped output can now be moved between panes intact via cmd | cmux set-buffer then paste-buffer.
• Whitespace-only text is accepted; only empty text is rejected.
• With a terminal on stdin and no text, it fails with "set-buffer requires text" instead of waiting for EOF.
• Adds CLITmuxCompatBufferContentTests covering piped stdin, -, argument preservation, and empty stdin.

^{Written for commit f2d114f. Summary will update on new commits.}

[coderabbitai]

Warning

Review limit reached

Next included review available in 19 minutes.

Check out review usage here.

View limit details

Limit details: You’ve used all 10 included reviews currently available.

You've used all free OSS reviews for now. Wait for the free limit to reset to keep reviewing this public repository.

Learn how review limits work.

Review configuration:

⚙️ Run configuration

Configuration used: Repository: manaflow-ai/cmux/.coderabbit.yaml

Review profile: ASSERTIVE

Plan: Advanced

Run ID: 2c259a30-5ac8-4c2b-87fc-d5ebaa8a3542

📥 Commits

Reviewing files that changed from the base of the PR and between 9bae42b and f2d114f.

📒 Files selected for processing (6)

• CLI/CMUXCLI+TaskHelp.swift
• CLI/cmux.swift
• Resources/Localizable.xcstrings
• cmux.xcodeproj/project.pbxproj
• cmuxCLITests/CLITmuxCompatBufferContentTests.swift
• docs/cli-contract.md

---

Thanks for using CodeRabbit! It's free for OSS, and your support helps us grow. If you like it, consider giving us a shout-out.

❤️ Share

• X
• Mastodon
• Reddit
• LinkedIn

_{Comment @coderabbitai help to get the list of available commands.}

[github-actions]

All contributors have signed the CLA ✍️ ✅
_{Posted by the CLA Assistant Lite bot.}

[github-actions]

Merge receipt for f2d114fbb0: every check was green at merge (16 verified; 15 skipped by policy). Full suite runs on main after merge.