Install script does not correctly detect Arm64 chip

[mcsantiago]

Please note we will close your issue without comment if you delete, do not read or do not fill out the issue checklist below and provide ALL the requested information. If you repeatedly fail to use the issue template, we will block you from ever submitting issues to Homebrew again.

• your problem was from running the official install or uninstall script?
• after installation: ran brew config and brew doctor and included their output with your issue? If you couldn't install: provided your OS version with the output of your issue?

What you were trying to do (and why)

Run the install script via the following command

/bin/bash -c "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/HEAD/install.sh)"

Here are the system specs:

System Specs
OS: macOS Monterey 12.0.1
MacBook Pro (14-inch, 2021)
Chip: Apple M1 Pro

What happened (include command output)

It turns out that UNAME_MACHINE="$(/usr/bin/uname -m)" will still resolve to x86_64 (and NOT arm64). The result is something like this:

Command output

()[~, 1s, SUDO]: /bin/bash -c "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/HEAD/install.sh)"

==> Checking for sudo access (which may request your password)...

==> This script will install:

/usr/local/bin/brew

/usr/local/share/doc/homebrew

/usr/local/share/man/man1/brew.1

/usr/local/share/zsh/site-functions/_brew

/usr/local/etc/bash_completion.d/brew

/usr/local/Homebrew

==> The following new directories will be created:

/usr/local/Cellar

/usr/local/Caskroom

/usr/local/Frameworks
  

What you expected to happen

I would expect that the installation will take place in /opt/homebrew for the arm64 architecture.

Step-by-step reproduction instructions (by running brew commands)

1. Run the following /bin/bash -c "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/HEAD/install.sh)".
2. Observe output discrepancy mentioned above.

[SMillerDev]

From where are you running this script?

[mcsantiago]

I'm not sure I understand the question. I'm running the command on my local macbook machine using iTerm.

[Bo98]

This means you are running your terminal in Rosetta mode. This will install the Rosetta version of Homebrew (x86_64).

[mcsantiago]

This will occur even if using the system bash (/bin/bash)? I'm not sure what this Rosetta mode is. What is the guidance for getting the correct uname in this case?

[carlocab]

Try

arch -arm64 /bin/bash ...

Though you should fix your terminal too. That'll cause you other surprises down the line.

[mcsantiago]

Thanks for the tip. I switched the terminal to the default system terminal (not iTerm) and I got the expected /opt/homebrew path. This was most unexpected and I have something else to look into with Rosetta mode. Thanks for the help! I'll close this issue now.

[Bo98]

General tips I can give is: make sure the "Open in Rosetta" checkbox is not ticked (control-click iTerm -> Get Info), and make sure you're not using an old version of iTerm.

[mcsantiago]

I double checked this. "Open in Rosetta" is not checked for iTerm2. It's still puzzling to me as to why the application opens in x86_64 land in the first place.

[SMillerDev]

Because it's not an ARM app.