Indicate git is unavailable; don't error out

[amcaplan]

WHY are these changes introduced?

This solves a number of issues of the form of #1782

Sometimes git is necessary; other times it's just a nice-to-have. When we make API calls, we use git to check the CLI sha. While it would be nice to have, we can live without it when it's unavailable; it's not worth the DX impact. Hence, we already introduced the ShopifyCLI::Git::available? method.

However, this method doesn't check properly, as the underlying Open3::capture2e will raise an error if the underlying executable isn't available at all. (For other errors, it will actually return output and a process status as expected.) This has resulted in cryptic errors when git isn't available on the system and the user just wants to make an API call.

On my local system, intentionally making a typo to demonstrate an unavailable executable:

[2] pry(main)> Open3.capture2e('git status')
=> ["On branch git-available-fix\nnothing to commit, working tree clean\n",
 #<Process::Status: pid 69095 exit 0>]
[3] pry(main)> Open3.capture2e('jit status')
Errno::ENOENT: No such file or directory - jit
from /opt/rubies/2.7.1/lib/ruby/2.7.0/open3.rb:213:in `spawn'

WHAT is this pull request doing?

Adds a rescue for the case that the git executable isn't present. This is OK because the purpose of the available? method is only used where we don't absolutely require git.

How to test your changes?

1. Have a system where git isn't installed
2. Run any command (e.g. login) that makes an API call

Update checklist

• I've added a CHANGELOG entry for this PR (if the change is public-facing)
• I've considered possible cross-platform impacts (Mac, Linux, Windows).
• I've left the version number as is (we'll handle incrementing this when releasing).

[pepicrft]

Thanks a lot for tackling this @amcaplan. I believe we'll need further work on this because git-related issues happen in Windows environments. My guess is that the way we access git only works in Unix-based systems.

[stephszeto]

Thanks for the explanation here, Ariel! Could you share a demo video that shows the updated behavior? I get what this does at a high level, but am wondering what the UX actually looks like.

Also re: Pedro's comment above, is this behavior only for Linux / Mac users that don't have Git?

[amcaplan]

@stephszeto I've tested this on a Windows VM to confirm it works all around.

Here's what happens when you shopify login without git installed:

Following the changes in this PR, here is the results of shopify login:

So rather than failing because git isn't installed, we shrug it off and continue making the login web request.

I also confirmed that when git is installed on Windows, we will pick it up properly with no error, so that wasn't the cause of the error prior to this PR.

[stephszeto]

Thanks for the screenshots!

Sometimes git is necessary; other times it's just a nice-to-have. When we make API calls, we use git to check the CLI sha. While it would be nice to have, we can live without it when it's unavailable

Do any of our CLI commands actually necessitate git to function properly, or is it a nice-to-have in all cases?

And if this solution indeed works for Windows, is there anything else we need to do for this error in general or should we have mitigated it with this PR?

[amcaplan]

Sometimes we do need git as an absolute requirement, for example when cloning an existing repository.

I believe that the linked error will be mitigated, but other errors won't be which is correct since those are the cases where we do need git.