You can set
`source=(git+https://github.com/openscad/MCAD.git#branch=dev)`
instead, which is the recommended way of doing this.
Also I see your build() function is empty so you might as well remove
it, cleaner output that way. And maybe combine all those rm's? I'm just
nitpicking at this point though ;p

Please see
https://wiki.archlinux.org/index.php/VCS_package_guidelines#VCS_sources
btw, specifically the #fragment bit.

Without doing this your pkgver() and other things will be printing the
wrong thing. Unless you're actually pulling files from both branches, in
which case I think you should be including both in the source array.

Thank you for reaching out and seeking advice rather than ignoring all
advice given. Cheers, katt.

On 24/07/2020 09:40, Dario Pellegrini wrote:
> Uh, how do you switch to a particular upstream branch from which to pick
> some files without git checkout?
>
> On Fri, 24 Jul 2020, 00:37 , <notify@aur.archlinux.org
> <mailto:notify@aur.archlinux.org>> wrote:
>
>     katt [1] filed a deletion request for openscad-mcad-dev-git [2]:
>
>     git checkout in package()
>
>     [1] https://aur.archlinux.org/account/katt/
>     [2] https://aur.archlinux.org/pkgbase/openscad-mcad-dev-git/
>