tmux -CC crash

Thanks for filing an issue! Please answer the questions below so I can help you.

• iTerm2 version: 3.5.20230322-nightly
• OS version: 13.2.1 (22D68) com.googlecode.iterm2.plist
• Attach a debug log, if possible. Instructions at https://iterm2.com/debuglog. Can't do this since it crashes the program.
• Attach a screen capture video if it would make the reproduction steps clearer. n/a
• Are you reporting a performance issue, excessive CPU usage, or a hang? Please attach a sample. Instructions at https://gitlab.com/gnachman/iterm2/wikis/HowToSample n/a
• Are you reporting a crash? Please attach the crash log. Instructions at https://gitlab.com/gnachman/iterm2/wikis/crash-logs iTerm2-2023-03-22-100931.ips
• Are you reporting excessive memory usage? Please attach a heap analysis: https://gitlab.com/gnachman/iterm2/wikis/heapshot n/a

PLEASE ATTACH YOUR PLIST FILE FOR BUG REPORTS! Seriously! I'll probably ask you for it if you don’t.

Detailed steps to reproduce the problem:

1. I ran the command tmux -CC
2. It crashes.
3. ....

What happened: iTerm crashes.

What should have happened: iTerm doesn't crash and instead opens a new tab using tmux underneath (as the non-nightly does).

From what I can tell through a git bisect, the issue first starts occurring in commit dbc493e502cdd02788e9def37ae43690e8a60b92.