Could not find XXX in locally installed gems, failed to run.

[AbdullahAs]

Testing in a new fresh app, and when attempting to run the extension, it indicates that some gems are not installed, despite the fact that they are installed.

Error:

Manually running: bundle list --name-only

[willkoehler]

tldr; if you've recently switched shells (bash to zsh) or made another equivalently large change to your shell, try rebooting your system. I know this is entirely unsatisfying. But this fixed a similar problem for me.

Full version

I had the same problem after I switched my MacOS default shell from bash to zsh. As part of the switch, I moved the contents of ~/.bashrc to ~/.zshrc So bash no longer had access to my Ruby version manager (asdf in my case) and was now running the system Ruby (which didn't have any gems installed)

I could reproduce the error if I opened a bash terminal in VSCode and ran bundle list --name-only

The default interactive shell is now zsh.
To update your account to use zsh, please run `chsh -s /bin/zsh`.
For more details, please visit https://support.apple.com/kb/HT208050.
sapphire:srb will$ bundle list --name-only
/System/Library/Frameworks/Ruby.framework/Versions/2.6/usr/lib/ruby/2.6.0/rubygems.rb:283:in `find_spec_for_exe': Could not find 'bundler' (2.3.4) required by your /Users/will/Working/PharmacySystems/SignylForRehab/srb/Gemfile.lock. (Gem::GemNotFoundException)
To update to the latest version installed on your system, run `bundle update --bundler`.
To install the missing version, run `gem install bundler:2.3.4`
        from /System/Library/Frameworks/Ruby.framework/Versions/2.6/usr/lib/ruby/2.6.0/rubygems.rb:302:in `activate_bin_path'
        from /usr/bin/bundle:23:in `<main>'
sapphire:srb will$ 

But if I opened a zsh terminal and ran bundle list --name-only, I would see the correct output

will@sapphire srb % bundle list --name-only
actioncable
actionmailbox
actionmailer
actionpack
actiontext
actionview
activejob
activemodel
.
.
.

The problem for me was that, for some reason, VSCode was still running extension shell commands in bash instead of zsh. So when the Standard extension attempted to run bundle list --name-only (via child_process.exec BTW https://nodejs.org/api/child_process.html#child_processexeccommand-options-callback) it was running in a bash shell.

After an afternoon of

• Learning about login shells, interactive shells, non-interactive shells, and their associated config files in bash and zsh...
• Discovering that if I ran VSCode from a terminal prompt (code .) or from Spotlight (cmd+space, search for Visual Studio Code, press enter), VSCode defaulted to the zsh shell and everything worked. But if I ran VSCode from Finder or the Dock, VSCode used the bash shell and everything did not work...
• Taking a deep dive in how VSCode interacts with the shell...

I finally tried rebooting my laptop (which I had not done since switching shells) After that everything worked. It "just works" now.

I don't know if this is the source of your problem. But I would look into what shell you normally run and what shell VSCode is using for extensions and in it's terminal. Hope this helps point you in the right direction.

[searls]

Eek, thanks @willkoehler! Hopefully this was the issue