Revision history [back]

As dornhege said, you most likely created at least two packages, and made them depend on eachother. Lets say you created packageA and packageB and made packageA depend on packageB and vice versa. What ros will try to do when you build packageA is first build all the depending packages of packageA, which includes packageB, so it builds packageB. To build packageB, it first builds all its dependencies, which includes packageA, so it wants to build packageA and at this point we are where we started again. This is what is called circular dependency.

Hope it helped.