Add rule to enforce mixing variable cases in AcquiaDrupalStrict

[balsama]

There doesn't seem to be any enforcement of mixing snake_case for variable names with lowerCamelCase. (For example, the following variable passed PHPCS: $commit_messageFailedPatches)

Can we add something to enforce one or the other (no mixing)?

Side note:
I was surprised that Drupal coding standards don't dictate one or the other:

Variables should be named using lowercase, and words should be separated either with uppercase characters (example: $lowerCamelCase) or with an underscore (example: $snake_case). Be consistent; do not mix camelCase and snake_case variable naming inside a file. - https://project.pages.drupalcode.org/coding_standards/php/coding/#functions-and-variables

🤷‍♀️

[TravisCarden]

Thanks, @balsama. I'm surprised to find that the Drupal coding standards don't dictate one or the other, too! They used to--and Coder used to enforce them. The best thing I could find about it on d.o is this: Allow camelCase for variable naming conventions [#2303963]. But that's a very old issue. In any case, this does seem like it should be solved in Coder module since the official standards do seem to dictate "one or the other". Would you care to create an issue there?

[danepowell]

I took the liberty of opening an upstream issue: https://www.drupal.org/project/coder/issues/3244409

[TravisCarden]

@balsama we're planning a new major version, so now is the perfect time to discuss breaking changes.

I personally would love to specify one or the other format, but I also know that some of our products use both in the same codebase and they might not appreciate the imposition. So I wonder if it wouldn't be best just add instructions to the README for how to choose one for yourself and add it to your own project config. If we wanted to be more aggressive, we could ship with a default (like snake_case, which Drupal core has used since the beginning of time), and add instructions for overriding it.