Fetching packages for local build requires expensive/failing API call

[ItachiSan]

Describe the bug
Downloading packages for a local build performs a call such as:

GET https://api.opensuse.org/build/Arch:Extra/standard/x86_64/_repository?binary=cudnn&binary=git&binary=cuda&binary=nvidia-utils&binary=perl-mailtools&binary=zlib-ng&binary=perl-error&binary=opencl-nvidia&binary=libglvnd&binary=egl-wayland&binary=egl-gbm&binary=egl-wayland2&binary=egl-x11&binary=perl-timedate&binary=libxext&binary=wayland&binary=libdrm&binary=eglexternalplatform&binary=libx11&binary=libxcb&binary=xorgproto&binary=default-cursors&binary=libxau&binary=libxdmcp&binary=xcb-proto&binary=mesa&binary=llvm-libs&binary=libxxf86vm&binary=libxshmfence&binary=lm_sensors&binary=spirv-tools&binary=python-yaml&binary=breezy&binary=mercurial&binary=python-dateutil&binary=subversion&binary=libyaml&binary=python-configobj&binary=python-dulwich&binary=python-merge3&binary=python-fastbencode&binary=python-patiencediff&binary=python-six&binary=libutf8proc&binary=apr&binary=apr-util&binary=serf&binary=python-urllib3&view=cpio

I believe this call requests a cpio archive of all needed dependencies.
However, in case of big dependencies, such as cuda, this might fail, leaving no packages in the cache and forcing a re-download which will fail.

Versions

• Operating system: Arch Linux
• Packages: osc 1.24.0-0 (from openSUSE:Tools)

To Reproduce
Steps to reproduce the behavior:

1. Create a new package with the provided PKGBUILD:
   PKGBUILD
2. Run: osc build; provide --http-debug to see all HTTP requests
3. On a personal connection, the request will likely take a very long time and/or fail

Expected behavior
Dependencies are downloaded properly and build succeed.

I would recommend downloading each package (can be done in parallel) or split the cpio accordingly

Screenshots, console outputs
Log of osc build --http-debug has been attached.
build.log

Additional context
I was hoping to get the packages via curl but it seems the URLs do not work.

[dmach]

This is how OBS is designed to work.
If the package is not available on a mirror or the download from mirror errors out or if the downloaded package doesn't have expected checksum (happens with noarch packages), it gets re-downloaded from OBS API.

I'm not sure if I can do anything about it directly in osc.

@adrianschroeter @mlschroe any thoughts?