| None of the other replies try to explain specifics of how this works, so let me illustrate an example of two teams collaborating to add Feature X to the monorepo without branching: 1) Team A checks in their code to provide Feature X. Their code is not used anywhere in the codebase yet, however full unit test coverage exists for the public API; this is required for code review. 2) Team B checks in their code to turn on Feature X in their product, gated under a command-line flag which by default uses the old behavior. 3) Team B checks in an integration test that flips the flag and makes sure everything works as planned. 4) If Team B requires changes to Feature X to get expected behavior, they communicate those changes to Team A and someone from either team (using available human resources) makes the changes. 5) Team B checks in a small change to flip the flag by default. 6) Team B monitors their product. If things go awry, only the very latest change is reverted and repeat (4). 7) Once stability is achieved, Team B checks in a change to remove the flag. |