Quick question regarding TeamCity dependencies

Question

Ok, this may be a silly question, maybe my English knowledge, or "just" my comprehesnion level, is fooling me, but what is the difference between snapshot dependencies and dependency triggers?

I guess the first means that when you build a project, TC makes sure the dependency is up to date, if it isn't it is rebuilt, and then it builds the original project, plus it won't allow builds in parallel. And the later means that if a new build of the dependency is built, it triggers a build of the project.

Also, if this is the case, I guess any "recursion" problem is already handled, like, eg: you force a build of a project with both features enabled, it checks the dependency and sees it needs to be rebuilt, and when it does so, the trigger isn't fired.

Are my assumptions right?

Answer 1

For the first part of your question, you answered it yourself.
Snapshot dependencies, force the dependent Build Configuration to build (if it's not up to date) before building the current Build Configuration.
Dependency triggers, make the current Build Configuration build after a successful build of the dependent project.

On the second part of your question, I think you are asking if Build Configuration A will run twice when it has both a Snapshot Dependency and a Dependency trigger to Build configuration B and you Run the Build Configuration A.
I tried this myself with Teamcity 5.1.2 and I saw that it only ran once.