Re: [PATCH v2] Add a document on rebasing and merging

From: Jonathan Corbet
Date: Wed Jun 05 2019 - 16:36:55 EST

On Tue, 4 Jun 2019 21:54:56 -0400
"Theodore Ts'o" <tytso@xxxxxxx> wrote:

> FYI, it looks like your patch somehow got hit by your text editor (or
> MUA's) line wrapping...

Weird, I haven't had a problem like that in decades. No idea what
happened here...

> > +
> > + - Realize that the rebasing a patch series changes the environment in
> > + which it was developed and, likely, invalidates much of the testing
> > that
> > + was done. A rebased patch series should, as a general rule, be treated
> > + like new code and retested from the beginning.
> Shouldn't "reparenting" be used in this paragraph?
> I suppose if a patch is getting dropped or modified that can
> invalidate some of the testing (although it really depends on the
> nature of what's being dropped or modified). And if it's just adding
> a Tested-by tag or a CVE number in the commit description, it's not
> going to invalidate any testing.

I had thought about it and chosen "rebasing", but I can change it.

> > +Another reason for doing merges of upstream or another subsystem tree is
> > to +resolve dependencies. These dependency issues do happen at times, and
> > +sometimes a cross-merge with another tree is the best way to resolve them;
> > +as always, in such situations, the merge commit should explain why the
> > +merge has been done. Take a momehnt to do it right; people will read those
> > +changelogs.
> It might also be useful to mention it might be useful to put the
> commits which are needed to solve the dependency problem on its own
> separate branch, based off of something like -rc2, and then each of
> the trees which need the prerequisite commits can merge in that
> branch.

That is (I think) in the following paragraph:

> Possible alternatives include agreeing with the maintainer to carry
> both sets of changes in one of the trees or creating a special branch
> dedicated to the dependent commits.

Perhaps that last line should read "...dedicated to the prerequisite
commits, which can then be merged into both trees" ?

Then perhaps I can finally declare victory on this thing? :)