> even the internal dependencies necessarily breaks the known contracts with other units The implication is that there are unit tests for those dependencies as

> even the internal dependencies necessarily breaks the known contracts with other units The implication is that there are unit tests for those dependencies as well. Changing the signature used for them, breaks the same contracts as a wrapping function signature change. Ofc, you may already have tests to cover alternate signatures (overloading, et al) but conceptually it's the same pitfall.