In D18923#232270, @epriestley wrote:

Probably the same, although they also didn't include browser vendor/version or console output so who knows.

In T9548#229910, @indygreg wrote:

https://www.mercurial-scm.org/repo/hg/file/default/contrib/phabricator.py is a Mercurial extension that allows you to send a series of changesets to Phabricator by calling Conduit APIs directly. The extension is currently tailored for the use cases of the Mercurial project itself, isn't distributed with Mercurial, and may require Mercurial 4.3. And it obviously bypasses Phabricator's built-in Mercurial server. But if you are willing to live with the caveats, you may find it a suitable workaround.

Indeed there are the predicted error messages in the phd log. I will try to explore more and see what is wrong. It is probably related to the issue I reported (T12726), likely some of the fields are incorrectly created by arcanist in the first place.

All that makes a lot of sense, I will try what you suggest and see if that was the source of the evil.

Ops, sorry :)

Did that, you can see the result at P2054. At least to me, nothing looks fishy...

Just tried it, didn't help :(

We have installed mercurial 3.9.2 both in the server and client, in fact we downgraded the client mercurial from 4.1 to 3.9.2 to match the versions, but nothing changed. The version of arcanist is 3c4735795a29 (pre-last commit) and phabricator is at ef839192aa5a (from Tuesday).

I tried to reproduce with other users, on the same phabricator install but there is only one user with a particular windows setup (that has nothing different from other users except for his particular windows machine) that is experiencing this problem. I tried following the stack trace and adding some error_log's on the php. But my php knowledge is close to zero. In any case something like this:

↑ I second @rros, commenting line line 71 of the PhabricatorRepositoryRefEngine class fixed it for me. Don't know about possible secondary effect but I have the feeling it was not working as intended anyway.