[darcs-devel] FullUnwind rebase behavior

[Ganesh Sittampalam]

On 11/05/2020 00:10, Ben Franksen wrote:

> I agree that WithDroppedDeps is not particularly complicated in itself.
> But the existence of NameFixups does complicate in-place editing of
> suspended patches.

Can you explain what the sticking point is? Intuitively I wouldn't have
considered it any worse than PrimFixup. For example if I wanted to
squash AddName into a patch that depends on that name, I'd just remove
the dependency.

I have a feeling that all the other cases where a NameFixup gets stuck
in the rebase state actually indicate bugs, though I'm not 100% sure of
that without thinking it through more carefully.


> Here is a typical scenario: I have made a simple but perhaps not
> completely trivial patch, followed by a large and complicated refactor
> with a detailed long comment that depends on the first one; and some
> more patches following. For some reason or other I want to fold the
> first patch into the second, but I don't want to loose the log for the
> second patch. So I suspend it, obliterate the first, and then either
> amend the second one manually (perhaps I have kept the file in my editor
> and re-save it to get the same end state); or I re-pull it from a clone,
> resolve conflicts, then unrecord and amend. In any case anything
> explicitly depending on the first patch looses the dependency. If I were
> notified about this immediately, and had a way to edit the affected
> patches immediately to replace the dependency, I would probably do so.
> 
> But of course it would be even better if this were done automatically.
> That requires an explicit (rebase) squash command that automatically
> pushes NameFixups that rename /all/ squashed patches to their (single)
> replacement. I am not sure the existing commute and force-commute
> functions for NameFixups would handle such a case correctly, i.e. the
> case where one or more renames "clash" with each other or with existing
> explicit deps.

I see, so we really need some kind of squash command to communicate the
user intent that we are actually replacing two patches with one.

I wonder if it needs to be within the rebase state, though. We could
also have a "darcs squash" command or perhaps "darcs amend-record
--squash" that integrates patches in the main repository with each
other. Not sure if it's any better or worse overall but it would
eliminate the need to deal with fixups.

Ganesh