I have a big Eclipse RTC project (Eclipse 3.7, using Jazz source control, millions of files) and I'd like to open it using IntelliJ IDEA (2017.3).
Has someone experienced editing a project in IntellJ while committing changes using Eclipse?
Which precautions should I absolutely use to avoid messing up the entire project?
Committing changes with Eclipse (in your repository workspace, or delivering to the stream) should have no impact with editing with IntelliJ.
You will just switch between the IDE in order to assign your changes to the right change sets before committing.
That being said, you could check if the Rational Team Concert Integration is compatible with your current IntelliJ 2017.x.