Trigger pipelines for merge requests

[smarkets]

Trigger pipelines for merge requests

[Jellby]

The tricky part would be detecting if a MR pipeline has already been triggered. In case of misconfiguration, a trigger may fail to create the desired jobs, in which case a naïve implementation (trigger if jobs do not exist, wait and repeat) would result in infinite triggers. The origin of a pipeline is passed as a CI variable (CI_PIPELINE_SOURCE) but it does not seem to be available in the API. Maybe Marge could leave a message in the discussion saying "I triggered a pipeline for [sha]", and check existing messages before triggering a pipeline? Or maybe it's just better to use some other service to trigger pipelines for MRs until it's properly implemented in GitLab (see https://github.com/shyiko/gitlab-ci-build-on-merge-request).

[snim2]

This has been overtaken by the new rules for GitLab CI which includes support for MR pipelines, so maybe needs a re-think?

[Jellby]

Triggering pipelines for MRs is no longer an issue (for me). But working with forks, or ensuring the pipeline is of the right type still is.

[snim2]

That's very useful, thanks. I work with forks so rarely I forget that they are quite different in GitLab.