Can't fetch sources for Qubes OS R4.2

Whenever I try fetching sources, it gives this error:

[user@work-qubesos qubes-builderv2]$ ./qb package fetch
16:49:37 [qb] Running stage 'fetch'
16:49:43 [qb.fetch.builder-rpm.fetch] copy-in (cmd): /usr/lib/qubes/qrexec-client-vm -- disp2451 qubesbuilder.FileCopyIn+-2Fbuilder-2Fplugins-2Ffetch /usr/lib/qubes/qfile-agent /home/user/qubes-builderv2/qubesbuilder/plugins/fetch
qfile-unpacker: Fatal error: Refusing to change to UID other than the caller's UID (error type: Success)
Traceback (most recent call last):
  File "/usr/local/etc/qubes-rpc/qubesbuilder.FileCopyIn", line 75, in <module>
    main()
  File "/usr/local/etc/qubes-rpc/qubesbuilder.FileCopyIn", line 64, in main
    subprocess.run(
  File "/usr/lib64/python3.12/subprocess.py", line 571, in run
    raise CalledProcessError(retcode, process.args,
subprocess.CalledProcessError: Command '['qfile-unpacker', '--allow-all-names', '--allow-unsafe-symlinks', '1000', '/builder/incoming']' returned non-zero exit status 1.
EOF

I have followed all the instructions for installing dependencies and setting the DispVM as default for work-qubesos.

Check that you’ve properly configured the qubes executor:
GitHub - QubesOS/qubes-builderv2: Next generation of Qubes OS builder

I’ve properly followed all the steps and I even copied the policy file as well. I’m not sure what to do here

What do you have in your builder.yml?

Here’s my builder.yml. I’m only trying to build the kernel here:

git:
  baseurl: https://github.com
  prefix: QubesOS/qubes-
  branch: release4.2
  maintainers:
    # marmarek
    - '0064428F455451B3EBE78A7F063938BA42CFA724'
    # simon
    - '274E12AB03F2FE293765FC06DA0434BC706E1FCF'

backend-vmm: xen
debug: true
verbose: true
qubes-release: r4.2

distributions:
  - host-fc37
  - vm-bookworm
  - vm-fc39
  - vm-fc40

templates:
  - fedora-39:
      dist: fc39
      options:
        - selinux
  - fedora-40:
      dist: fc40
      options:
        - selinux
  - debian-12:
      dist: bookworm
      options:
        - firmware
  - whonix-gateway-17:
      dist: bookworm
      flavor: whonix-gateway
      options:
        - minimal
        - no-recommends
  - whonix-workstation-17:
      dist: bookworm
      flavor: whonix-workstation
      options:
        - minimal
        - no-recommends

components:
  - builder-rpm:
      packages: False
      branch: main
  - linux-kernel-latest:
      url: https://github.com/QubesOS/qubes-linux-kernel
      branch: main
      timeout: 21600

#executor:
#  type: docker
#  options:
#    image: "qubes-builder-fedora:latest"

executor:
  type: qubes
  options:
    dispvm: "@dispvm"

stages:
  - fetch
  - prep
  - build
  - post
  - verify
  - sign:
      executor:
        type: local
  - publish:
      executor:
        type: local
  - upload:
      executor:
        type: local

What template do you use for work-qubesos and qubes-builder-dvm?
I’ve tried it with fedora-40-xfce template and I didn’t have this error with your config.

Fixed! I was using fedora-39 and using fedora-40-xfce fixed it. Thank you so much!

However, I seem to be getting a new error when prepping:

00:36:11 [qb] An error occurred: linux-kernel-latest:host-fedora-37.x86_64:kernel.spec: Failed to get source information: Failed to run '/usr/bin/qvm-run-vm -- disp7378 env -- VERBOSE=1 DEBUG=1 BACKEND_VMM=xen DIST=fc37 PACKAGE_SET=host bash -c '/builder/plugins/source_rpm/scripts/get-source-info /builder/linux-kernel-latest /builder/linux-kernel-latest/kernel.spec fc37'' (status=1)..
00:36:11 [qb] 
Traceback (most recent call last):
  File "/home/user/qubes-builderv2/qubesbuilder/plugins/source_rpm/__init__.py", line 173, in run
    executor.run(
  File "/home/user/qubes-builderv2/qubesbuilder/executors/qubes.py", line 377, in run
    raise e
  File "/home/user/qubes-builderv2/qubesbuilder/executors/qubes.py", line 346, in run
    raise ExecutorError(msg, name=dispvm)
qubesbuilder.executors.ExecutorError: Failed to run '/usr/bin/qvm-run-vm -- disp7378 env -- VERBOSE=1 DEBUG=1 BACKEND_VMM=xen DIST=fc37 PACKAGE_SET=host bash -c '/builder/plugins/source_rpm/scripts/get-source-info /builder/linux-kernel-latest /builder/linux-kernel-latest/kernel.spec fc37'' (status=1).

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "/home/user/qubes-builderv2/qubesbuilder/cli/cli_base.py", line 76, in __call__
    rv = self.main(*args, standalone_mode=False, **kwargs)
         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3.12/site-packages/click/core.py", line 1078, in main
    rv = self.invoke(ctx)
         ^^^^^^^^^^^^^^^^
  File "/usr/lib/python3.12/site-packages/click/core.py", line 1688, in invoke
    return _process_result(sub_ctx.command.invoke(sub_ctx))
                           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3.12/site-packages/click/core.py", line 1719, in invoke
    rv.append(sub_ctx.command.invoke(sub_ctx))
              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3.12/site-packages/click/core.py", line 1434, in invoke
    return ctx.invoke(self.callback, **ctx.params)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3.12/site-packages/click/core.py", line 783, in invoke
    return __callback(*args, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3.12/site-packages/click/decorators.py", line 45, in new_func
    return f(get_current_context().obj, *args, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/user/qubes-builderv2/qubesbuilder/cli/cli_package.py", line 75, in prep
    _component_stage(
  File "/home/user/qubes-builderv2/qubesbuilder/cli/cli_package.py", line 41, in _component_stage
    p.run(stage=stage_name)
  File "/home/user/qubes-builderv2/qubesbuilder/plugins/source_rpm/__init__.py", line 178, in run
    raise SourceError(msg) from e
qubesbuilder.plugins.source.SourceError: linux-kernel-latest:host-fedora-37.x86_64:kernel.spec: Failed to get source information: Failed to run '/usr/bin/qvm-run-vm -- disp7378 env -- VERBOSE=1 DEBUG=1 BACKEND_VMM=xen DIST=fc37 PACKAGE_SET=host bash -c '/builder/plugins/source_rpm/scripts/get-source-info /builder/linux-kernel-latest /builder/linux-kernel-latest/kernel.spec fc37'' (status=1)..

I don’t have this error when I run ./qb package prep after ./qb package fetch finished successfully.
Did you change the template for both work-qubesos and qubes-builder-dvm to fedora-40-xfce?
Did you install dependencies for both work-qubesos and qubes-builder-dvm in fedora-40-xfce?

Works now, I had to reinstall dependencies