Brew zsh hangs on $(...) command substitution in Big Sur 11.0.1

[miiaow]

Can anyone reproduce this on Big Sur 11.0.1?

install zsh from brew

brew install zsh

verify version

/usr/local/bin/zsh --version
zsh 5.8 (x86_64-apple-darwin20.1.0)

start zsh without rcs (this should start a new shell):

/usr/local/bin/zsh --no-rcs
Torgeirs-MacBook-Pro%

try to enter the following in the new shell (it should hang):

echo $(date)

To me it seems like all command substitution using $() causes zsh to hang.
Backticks seem to work though.

[Aljutor]

Yes, I have same problem, zsh 5.8, Big Sur 11.0.1

[johndbritton]

Can anyone reproduce this on Big Sur 11.0.1?

Yes, I have the same issue. For the time being I've switched my default shell to the version of zsh provided with macOS.

In case others end up on this thread via Google like me, here's a temporary workaround:

Open Terminal.app preferences and set Shells open with to Command (complete path): and use /bin/zsh for the macOS provided zsh binary.

Now when you open Terminal.app zsh will no longer hang. If you want to update your default user shell you can use sudo dscl . -create /Users/$USER UserShell /bin/zsh.

[miiaow]

Issue created: Homebrew/homebrew-core#64921

[fxcoudert]

I've identified it as a zsh bug with clang 12, and reported it to the zsh developers.
A workaround is being put in place for Homebrew: Homebrew/homebrew-core#64923

[carlocab]

This has now been fixed. Quoting the second part of this comment:

One hour from report to analysis, upstream report, and local workaround is not bad for a volunteer-based team. Please consider sponsoring our work if you can: https://github.com/sponsors/Homebrew

Thanks for getting this done so quickly, @fxcoudert !