TBH, I'm confused about $xaction being treated as an array in line 126.

"tooling for chains of diffs" might need its own topic, with a design of the what the whole thing should look like in an ideal world, and how to get to it.
Even if not all of the stuff fits nicely into Phorge, there's probably a lot that can work, and some conduit methods can be added to implement the rest.

mmm... I've never really worked where many changes are made of lots of dependent revisions - it's possible I've never even seen a chain of 3 revisions in the same repo. So I'm not sure about workflows for this kind of scenarios.

Ok, so here's my thoughts on moving this forward:

I think we can just have array_fuse() accept null and return an empty list, because it's only there to simplify calling sites.

It hadn't happened in a while, so I guess it was something strange in my machine.

I don't see a reason to open it. If you know what you're doing and want to enable this feature, you can just change the code locally.

This discussion (and disagreement) is exactly the reason why we need a CLA ASAP.
While consulting with a relevant legal counsel.

What are the reasons for doing commit message rendering on the server side?

We can probably come up with a way to allow an extension to customize the "render template" implementation without forking (e.g., just add a hook in differential.getcommitmessage), but it would have to be very carful about the whole form-thing.
Maybe just adding an "for landing" flag in differential.getcommitmessage (or adding a different method) would solve this problem...

In T15364#8281, @ton wrote:

The template is actually generated server side, not in arcanist, so it just a matter of getting the BSD Phorge server to have the right opinions.
Some of the sections can be configured already

Please point me in the right place in the code where I can find the template

Alternatively - there's also arc land --hold, which does almost everything except for the git push, which would allow the user to update the commit message. Have anyone tried that?

thanks @ton - these look very actionable:

In T15249#8232, @ton wrote:

@avivey today I tried arc patch to download a bunch of Diffs.

Some diffs check out OK. Lots of Diffs fail to be fetched, I get a very useless error message:

Exception
strpos(): Passing null to parameter #1 ($haystack) of type string is deprecated
(Run with `--trace` for a full exception trace.)