Re: rebase -p loses amended changes

> On Wed, Apr 4, 2012 at 4:55 AM, J Robert Ray <jrobertray@gmail.com> wrote:
>> On Sat, Mar 31, 2012 at 2:39 AM, Jon Seymour <jon.seymour@gmail.com> wrote:
>>> On Sat, Mar 31, 2012 at 8:35 PM, Thomas Rast <trast@student.ethz.ch> wrote:
>>>> Jon Seymour <jon.seymour@gmail.com> writes:
> orrectness point of view.
>>
>> I thought there would be more concern about the silent data loss.
>> Instead of throwing away the amended changes I would prefer the rebase
>> to at least fail, if not have the problem require manual conflict
>> resolution.
>>
>> A warning at the time of the amend could confuse or scare users. But a
>> mention of this problem in the rebase docs would help.
>
> It'd be quite expensive to attempt to detect cases where this might be
> a problem, but let's articulate, as a thought experiment, what such a
> solution might look like - I am not suggesting that it is a good idea,
> but the thought experiment might be illustrative.
>
> Suppose you have a merge of a A and B that produces M, which is then
> amended as M'.
>
> During rebase, you redo the merge A and B. If there are no conflicts,
> then compare M with M' to produce D. You now have enough information
> to reproduce the amended commit M' during a rebase (merge Ar and,Br
> then apply D).