In this chapter, we are going to cover the creation of a custom check-in policy. We'll go through the following high-level topics:
Implementation—what it takes to write the code
Deployment—what is required to get this to your end user
Useful policies—policies already created by the community
Check-in policies are very useful as you can make sure that certain requirements are met before a check is made that might not be meeting some standards. In my opinion, it's one of the easier customizations to perform. It's also important to mention that check-in policies are currently only supported by TFVC.