On Thu, Feb 14, 2019 at 02:10:53PM -0800, Junio C Hamano wrote: > Elijah Newren <newren@xxxxxxxxx> writes: > > > The only thing I seem to be able to retain is the following: "git > > diff D..E is totally useless and should be an error because (1) it > > doesn't do what I expect and (2) for folks that want the behavior > > currently gotten with that syntax can instead just use a space instead > > of a double dot." > > That sums up pretty nicely. diff is fundamentally an operation > between two endpoints, so the range notation a..b does not work > nicely with it at the conceptual level. > > When we realized that we can take advantage of the above fact, and > reuse a range notation to mean something that is generally useful in > the context of diff, such as 'one end of the comparison is the merge > base between a and b, and the other end is b', it was too late to > use "a..b", as an early adopters of Git was already used to the fact > that "a..b" happened to mean the same thing as "comparison of one > end is a, the other end is b", pretty much implemented without much > thought. > > It might be _possible_ to spend a year (i.e. 4 cycles) to start > warning when two-dot notation is used for "git diff" (only, not any > plumbing like "git diff-files") and tell the user to use the more > logical two-end notation "git diff A B" and then eventually error > out when two-dot notation is used, while retaining the three-dot > notation throughout and to the eternity. I am not sure if it is > worth the deprecation cost, though. > Instead of outright deprecating it, would it make sense to include a configuration option, say "diff.sensibleDots", that would enable a user to set the dots to the other form if they desire? This has bugged me for long enough that if there's a desire for this from others, I'm willing take on the effort of making this change. Thanks, Denton
