Hi Junio, I'm really sorry, I thought the switch of default and migration plan had already been agreed on in our discussion of my earlier patch. Specifically, you wrote (https://lore.kernel.org/git/xmqq7cmdpbhq.fsf@gitster.g): First allow to configure the custom algorithm from the command line option (and optionally via a configuration variable) and ship it in a release, start giving a warning if the using script did not specify the configuration or the command line option and used the current default and ship it in the next release, wait for a few releases and then finally flip the default, or something like that. So I thought it would be helpful to follow-up with a patch that implements the approach you outlined. But I totally understand that it might be worth discussing this more. Actually, I do agree with your assessment that this warning is not great UX. I think relying on `diff.algorithm` is a natural idea, but it might also be confusing for users. At least to me, the name `diff.algorithm` suggests that it's the algorithm used for "git diff", but I might not realize that it also influences how my merges are done. It's probably common to want different algorithms for those situations as they require different speed and accuracy trade-offs. In any case, I'm happy to withdraw this patch. Would it be helpful if I start a new thread on the mailing list, independently from this patch, to discuss if and how the default should be switched? Best, Antonin