nix install on macos with coreutils on path

[ciiqr]

Is your feature request related to a problem? Please describe.
Just ran into an issue helping someone install nix. the chmod -R ugo-w "$NIX_ROOT/store/" line in the multi user install script was failing without any error messages (running it manually showed an exit code of 1, but even with -v no useful error messages were logged). Turns out they had the coreutils brew package installed and linked into their path, so instead of using the system version of chmod it was the gnu version.

Describe the solution you'd like
Check in the install script that chmod doesn't point to homebrew/coreutils and warn the user about the issue and fail the install.

Describe alternatives you've considered
Could always use /bin/chmod instead of relying on the chmod from the path. 🤷

[abathur]

AFAIR this shouldn't be a durable homebrew problem, but a short-term problem with a specific coreutils version or set of versions. Can you see if brew upgrade coreutils gets it working?

More context in:

• Installation error on OSX Catalina 10.15.7 (2012 iMac) (Caused by homebrew version of chmod) #6671

[ciiqr]

I can check with them later to see if this works. If it is in fact a version specific error though, maybe we can detect the issue by checking the output of chmod --version? Otherwise users are just left with the generic Oh no, something went wrong which can be exceptionally discouraging, especially since a lot of people are already hesitant to use nix at all.

[kkroening]

Confirming all of the above. I was stumped by the mysterious "Oh no, something went wrong" error and finally figured out chmod is returning exit code 1, and came across this issue.

Temporarily bypassing coreutils in my bash profile fixed it:

# PATH="${HOMEBREW_PREFIX}/opt/coreutils/libexec/gnubin:$PATH"  # temporarily disabled!

The brew upgrade coreutils approach is probably better, but this is at least a datapoint that changing the installer to use /bin/chmod could be a general fix.