On Sun, Feb 23, 2020 at 11:47:32PM -0500, Jeff King wrote: > One thing that compels me is the recent report that we still build with > common crypto by default on macOS, which was definitely _not_ intended. > That's a bug that can be fixed, but it wouldn't have happened in the > first place if we only supported sha1dc. I just noticed you were the original reporter there, too. So I guess it compelled you, too. ;) If we do want to keep the other implementations around, another thing that might be worth doing is to teach t0013 to complain when the collision-detecting sha1 is not in use (i.e., rather than auto-skipping when built without DC_SHA1, require the user to set a special NO_REALLY_I_CHOOSE_NOT_TO_USE_DC_SHA1_AND_AM_AWARE_OF_THE_IMPLICATIONS variable). That would provide a cross-check on the build flags. -Peff