ci(lint): add shell linter - Differential ShellCheck

[jamacku]

It performs differential and full ShellCheck scans and reports results directly on GitHub.

differential-shellcheck Action produce reports in SARIF format. GitHub understands this format and is able to display it nicely as a PR comment, and on the Files Changed tab, such a defect is easier to spot and fix.

Documentation is available at @redhat-plumbers-in-action/differential-shellcheck. Let me know If you are missing some feature or setting. I'm always happy to extend functionality.

[ericcurtin]

Thanks for the contribution @jamacku

Unfortunately I avoid GitHub Actions plugins if at all possible in inotify-tools, unless I have no other option.

I would prefer just a shellcheck stage in here:

https://github.com/inotify-tools/inotify-tools/blob/master/build_and_test.sh

There is a reason I do things this way, it's to avoid vendor lock-in (in case we have to migrate from GitHub in future for whatever reason) and so people can easily run equivalents on their local machines to fix and debug build issues.

Also, when you run it in the build_and_test.sh script it will run many different versions from the many different platforms, sometimes this is actually a good thing as the different versions may find different things and you can choose to turn of certain versions of shellcheck if needs be.

I have avoided shellcheck because I have used it in the past and found it a tad pedantic.

But if someone put in the work to add in build_and_test.sh I'd likely merge anyway.

[jamacku]

Hi @ericcurtin,
I understand your reasoning. Unfortunately, it's not possible to run differential-shellcheck locally.

• Enable to run Differential ShellCheck locally 🏙️  redhat-plumbers-in-action/differential-shellcheck#179
• Consider adding support for pre-commit hook ⚓  redhat-plumbers-in-action/differential-shellcheck#234

Feel free to close this request. I'll come back once it would be possible to run differential-shellcheck locally.