Robert Ramey:
Here is where we differ. Now when someone checks in a breaking change. errors pop up all over the place in test results that the author who caused the problem doesn't have any reason to check. He who has had his library broken has to investigate the cause of the sudden breakage and trace down to its source and then complain. This is a huge pain in the neck and costs a lot of time and frustration.
What's the alternative? In Boost release 1.36, libfoo 1.36 has to work against Boost 1.36, not Boost 1.35. Testing it only against Boost 1.35 allows one to be smug and claim that any failures aren't one's fault, but doesn't help the release process. Trunk does, by testing tentative libfoo 1.36 against tentative Boost 1.36. Sort of.