rbenv install 3.4.4 apparently successful, but ruby 3.4.4 not found

[jen2014]

I can't find any way out of this: rbenv install 3.4.4 apparently works, but ruby is not found with ruby -v.
I am on a MacOS 15.5 Apple M4 Pro.
I have looked up many web pages on the subject, uninstalled Homebrew and rbenv as best I could, and tried to do a clean install

rbenv install 3.4.4
ruby-build: using openssl@3 from homebrew
==> Downloading ruby-3.4.4.tar.gz...
-> curl -q -fL -o ruby-3.4.4.tar.gz https://cache.ruby-lang.org/pub/ruby/3.4/ruby-3.4.4.tar.gz
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100 22.1M  100 22.1M    0     0  24.0M      0 --:--:-- --:--:-- --:--:-- 24.0M
==> Installing ruby-3.4.4...
ruby-build: using libyaml from homebrew
-> ./configure "--prefix=$HOME/.rbenv/versions/3.4.4" --with-openssl-dir=/opt/homebrew/opt/openssl@3 --enable-shared --with-libyaml-dir=/opt/homebrew/opt/libyaml --with-ext=openssl,psych,+
-> make -j 14
-> make install
==> Installed ruby-3.4.4 to /Users/windbreiz/.rbenv/versions/3.4.4
NOTE: to activate this Ruby version as the new default, run: rbenv global 3.4.4
rbenv global 3.4.4
ruby -v
ruby 2.6.10p210 (2022-04-12 revision 67958) [universal.arm64e-darwin24]

Verifying rbenv versions:

rbenv versions
  system
* 3.4.4 (set by /Users/windbreiz/.rbenv/version)

Looking for the installed ruby:

ruby -v
ruby 2.6.10p210 (2022-04-12 revision 67958) [universal.arm64e-darwin24]

(So, only the Apple version is showing up, not 3.4.4 supposedly installed by rbenv.
My .zshrc contains the following:

eval "$(rbenv init -)"
eval "$(/opt/homebrew/bin/brew shellenv)"

# assuming that rbenv was installed to `~/.rbenv`
FPATH=~/.rbenv/completions:"$FPATH"

autoload -U compinit
compinit

I am sure something is wrong somewhere, but other than restarting everything from scratch with an exhaustive guide, I don't know where to start.
Any tip will be appreciated.

[mislav]

Hi, it looks like both rbenv and Ruby 3.4.4 are all installed correctly, but "system" ruby 2.6 takes precedence somehow. This could be to the ordering of locations in PATH. You can do echo $PATH (or print -l "${path[@]}" in zsh to make the output more readable) and which -a ruby to see what is going on:

• /usr/bin/ruby is Ruby 2.6 that is currently always active for you, but you instead want rbenv's ruby to take precedence;
• ~/.rbenv/shims/ruby is what you want, so you will want to see ~/.rbenv/shims high up in your PATH.

The eval "$(rbenv init -)" in your zshrc looks good and that should have been what prepends ~/.rbenv/shims to your PATH, making sure that ruby invocations always go through rbenv. Somehow, on your system, that isn't the case, but I think with just a little bit inspection, you will easily find out what went wrong. Please let us know when you do!

[jen2014]

Hi mislav, thanks for the help.
As shown below, the list indeed seems to be missing the installation path: /Users/windbreiz/.rbenv/versions/3.4.4 at the top.

% print -l "${path[@]}"
/opt/homebrew/bin
/opt/homebrew/sbin
/usr/local/Cellar/git/2.19.1/bin
/usr/local/bin
/usr/bin
/bin
/usr/sbin
/sbin
/usr/local/Cellar/ffmpeg/4.1/bin
/var/run/com.apple.security.cryptexd/codex.system/bootstrap/usr/local/bin
/var/run/com.apple.security.cryptexd/codex.system/bootstrap/usr/bin
/var/run/com.apple.security.cryptexd/codex.system/bootstrap/usr/appleinternal/bin
/opt/X11/bin
/Library/Apple/usr/bin

And which -a ruby still shows the same unwanted system ruby version:

% which -a ruby
/usr/bin/ruby

Is there a way to correct that situation?

[mislav]

Hi, I suspect that the rbenv init line in your zshrc still isn't working.

Let's circle bash to your zshrc:

eval "$(rbenv init -)"
eval "$(/opt/homebrew/bin/brew shellenv)"

Let's change that to:

eval "$(/opt/homebrew/bin/brew shellenv)"
eval "$(~/.rbenv/bin/rbenv init - zsh)"

And then restart your shell/terminal window for the changes to take effect. Take note of any potential error messages during shell startup. Here I am assuming you've installed rbenv via git checkout into ~/.rbenv. In case you've installed by Homebrew, you would just reference rbenv as rbenv instead of ~/.rbenv/bin/rbenv, because Homebrew would have ensured that it's in PATH.)

[jen2014]

Thanks a lot, that worked! I had actually tried eval "$(rbenv init - zsh)" -- I installed my rbenv with homebrew -- but discarded it as it was generating an error. But also, it was coming first in the .zshrc.
Could you confirm or explain why having eval "$(/opt/homebrew/bin/brew shellenv)" first is important?
Thanks.

[mislav]

Sure thing: Homebrew places binaries for all installed tools under /opt/homebrew/bin. This directory is not in PATH by default, so even after you've installed packages like rbenv with Homebrew, they won't be found in PATH until you've finished setting up Homebrew in your shell. This is, of course, done by evaluating the brew shellenv script. That script also sets up other things, like making sure zsh completions work for Homebrew-installed software, but the PATH change is the most important.