Jenkins will not build after Git merge

tomslickers

I'm working on a DevOps solution that includes SQL Change Automation, Git, and Jenkins, but I can’t seem to get Git to reliably trigger a Jenkins build when doing a Git merge.

In Git, I have three “environment” branches (test, staging, master) plus a “feature” branch named feature1. 

If I commit a change to feature1, a build is triggered. 

If I then merge feature1 into another branch (e.g. test), GitHub does a push to Jenkins (I can see this in the GitHub Hook Log), but no build is triggered because Jenkins (or Git, not sure which) doesn’t think there were any changes:

tomslickers

This was solved using Jenkins multi-branch pipelines. Any Git branch will build now when a push or merge is done, and I only need one Jenkins project for each database.

JamesPhillips

I’ve seen a similar issue before where it’s not calculating changes correctly.  Try this as a fix. 

In Jenkins go to the job and go to job configuration. 

Once there find the Source Code Management under additional behaviors add a Calculate Changelog against a specific branch.  

Then enter the names of the repos and branch. 

This forces the comparison. 

tomslickers

Thanks, but that did not seem to help. I added the Additional Behaviour with my repos name and "origin/test" as the branch, but the GitHub Hook Log still reports "No changes". Is there some way to avoid this check (for No changes) altogether? If Git does a push, I want Jenkins to do a build.

tomslickers

I'm starting to think this is not possible with a single Jenkins project. I found a few posts about this but no good solutions:

https://stackoverflow.com/questions/19283187/jenkins-does-not-build-branch-after-merging-with-another-one

https://github.community/t5/How-to-use-Git-and-GitHub/Trigger-Jenkins-job-when-a-pull-request-is-merged-to-a-branch/td-p/10190

https://stackoverflow.com/questions/41660240/jenkins-wont-trigger-build-after-merging-a-pull-request-in-github

The only thing I can think of is create four Jenkins projects for each database; one to build the feature branches, and one each for Test/Staging/Production. This is not ideal because I have about 25 databases to deal with, but it would largely be a one-time setup.

I don't quite understand the Jenkins multi-branch pipelines but that might a more compact way to this.