On Tue Sep 17, 2024 at 22:51, Junio C Hamano <gitster@xxxxxxxxx> wrote: > > So, as long as we can explain the behaviour to the end-user well, I > do not care too deeply. My impression was that avoiding it by just > taking advantage of the atomicity afforded by create_symref() looked > like a low hanging fruit, but that can be done by somebody who are > curious to see how involved such a change actually is and can be > safely left as a #leftoverbit ;-). > > Thanks. Now that I've poked around a bit (cf. https://lore.kernel.org/git/20240919121335.298856-2-bence@xxxxxxxxxxxxxx/T/#u) that fruit does seem to hang lower :) My idea is the following: Add a new member to the ref_update struct that records the value of the ref _before_ the update transaction (in the files-backend), that can then be accessed post transaction_commit in refs_update_symref. If we want to pass this info up to the caller of refs_update_symref then I guess the only option is to pass an extra buf where we can write this, or if we're fine with update_symref itself doing the printing we probably need a bool to turn this on/off. My PoC seems to work and pass tests, although judging from previous interactions I'm probably overlooking a couple of edge cases. Does this seem reasonable? Best, Bence
