Be Careful with BlobID Value During Merge of YML Files

It is a copy of my article initially posted here to keep all things in one place.

Let's imagine that you have a Sitecore project with configured Unicorn serialization. And you are working on this project with the team. One day you get a conflict in one of your files in Media Library:

It is important to remember that BlobID is important as well as Value property. If during solving of conflict you update only Value and update your item then nothing will be changed. Media item will still have old media attached to the item.

We have faced with this issue during the automation of our processes. We wrote a CI script that creates YML serialized files from the SXA theme. We updated the Value but didn't touch BlobID, it caused items to remain the same.