Option to force run check-merge-conflict

[vinayinvicible]

check-merge-conflict only runs when it detects merge/rebase in progress.
This means it will always pass on CI setups.

Am not sure if this should be fixed specifically for check-merge-conflict or make a generic CI functionality available via pre-commit

[asottile]

This is a bit intentional, the hook is especially susceptible to false positives when run outside of a merge conflict due to matching things like this

That said, you could easily write a local pygrep hook which works almost the same, something like this:

-   repo: local
    hooks:
    -   id: naive-check-merge-conflict
        name: naive check-merge-conflict
        entry: '^(<<<<<<< |======= |>>>>>>> |=======$)'
        language: pygrep

for example against pre-commit-hooks:

$ pre-commit run naive-check-merge-conflict --all-files
naive check-merge-conflict...............................................Failed
hookid: naive-check-merge-conflict

CHANGELOG.md:39:=======

Might be able to get away with exclude_types: [markdown] to make it work better?

$ pre-commit run naive-check-merge-conflict --all-files
naive check-merge-conflict...............................................Passed

[vinayinvicible]

Setting up a local hook will run it on developer's machine too.

Our codebase is huge and we were not using pre-commits from the start. So, CI is setup to run using source and origin options instead of all files.

So, I am just looking for a way to trigger this hook on our CI setup.

[asottile]

Here's some previous ideas I've sketched out for running a different set of hooks in CI vs locally: pre-commit/pre-commit#765 (comment)

basically two ideas: either using stages: [manual] or separate config files with -c

[vinayinvicible]

I wasn't aware of manual stage being added.
Even to use this, I don't want to duplicate the merge conflict logic into pygrep. Is it possible to support --force as an optional argument for check-merge-conflict.

[asottile]

Sure, would need a PR but I'd accept that :)

Maybe --assume-in-conflict?