Re: [PATCH v4 5/9] rebase: add coverage of other incompatible options

Phillip Wood [off-list ref] writes:

On reflection that is only true for (B). I agree that we should error
out on (A) which we don't at the moment.

I'd support a change that errors out on (A) and (C) but continues to
allow (B) and (D). I think we can do that with the diff below

Thanks, both of you, for well reasoned design work and respectful
communication.