bug#42765: 26.3; project-find-regexp broken in Emacs 26.3

[Dmitry Gutov]

On 08.08.2020 19:42, Philip K. wrote:
> I managed to fix this by installing a newer Xref version from ELPA, but
> I think this situation should be handled more gracefully. Is there a
> reason that project.el doesn't depend on the newer Xref version?

I have pushed a fix for, hopefully. Commit 319463920c.

It inverts the dependencies, making xref only depend on project.el 
implicitly, by requiring Emacs >= 26.3, and making it work with the 
older API. And making project depend on the latest xref.

Hopefully this reversal won't create any problems when upgrading.