"config-errors" workflow on a project that built cleanly 3 months ago

We’ve recently tried to build a branch of one of our projects and found that it very quickly enters the Error state in a workflow “config-errors” which isn’t defined in our config. There don’t seem to be any logs we can access that detail the cause of the error.

The last successful build was April 24 2024. The project uses config version 2.1

I have run the config through the linter on the circle website, and ran circleci config validate on a local copy of the repo and neither is indicating any errors in the config file.

I’ve attempted re-running the workflow on the branch that first failed, created a new branch with no changes from main, and triggered a build on the main branch - all of which are failing the same way. The last successful build was on the main branch and it hasn’t changed since it last ran successfully.

The project uses an ssh user key, and I’ve verified that the key is still active and should be working on github, both circleci and github show the same SHA256 hash for the key.

Other projects in our organization are building as normal.

I’m not finding anything useful with a google search or searching the circle docs or this discussion site for “config-errors”.

I’m at a bit of a loss as to how to further troubleshoot this issue.

This error turned out to be a syntax error in a regular expression - we had /*/ when we should have had /.*/