Assert Lefthook is running with an environment variable

[paduszyk]

⚡ Summary

Setting LEFTHOOK environment variable to true (or 1) when Lefthook is running.

Alternatively, LEFTHOOK_VERSION variable can be added or runtime to indicate that one runs Lefthook with an extra information the release number.

Value

Currently, one can disable Lefthook via LEFTHOOK=0. But I guess there is no way to detect Lefthook running. For example, some development/debugging tools may be interested whether they are loaded/used within pre-commit check. Resolving this issue would help.

Behavior and configuration changes

I guess this would not be a breaking change. I am not familiar with the codebase structure, but if you find the idea interesting I can try to implement and add tests.

[mrexox]

Hey! Have you considered using env option? I think manually adding such envs is better because you don't rely on the tool's implicit behavior.

[technicalpickles]

Restating the requst, I'm reading this as setting an environment variable that programs can use to 'sniff' that lefthook is running. This is pretty common for CI, as a comparison:

• GitHub Actions: CI=true, GITHUB_ACTIONS=true
• Buildkite: CI=true, BUILDKITE=true

I think it's less about having an implicit environment variable for tools, as much as it is as a way to check and do something different if run by lefthook. I can imagine a few cases:

• warning / suggesting that lefthook should be setup, and rely on the pre-commit hook
• adjust formatting output to optimized for lefthook (less noise/preamble)

I don't know what you'd call it though, since LEFTHOOK already is used, unless lefthook sets it to 1 when running 🤔