borgbackup fails to build with Python 3.10.0a6.

build/lib.linux-x86_64-3.10/borg/testsuite/archiver.py::ArchiverTestCase::test_exclude_keep_tagged PASSED [  6%]
build/lib.linux-x86_64-3.10/borg/testsuite/archiver.py::ArchiverTestCase::test_exclude_keep_tagged_deprecation Fatal Python error: Segmentation fault

Current thread 0x00007f149ed75740 (most recent call first):
  File "/builddir/build/BUILD/borgbackup-1.1.15/build/lib.linux-x86_64-3.10/borg/patterns.py", line 148 in match
  File "/builddir/build/BUILD/borgbackup-1.1.15/build/lib.linux-x86_64-3.10/borg/archiver.py", line 607 in _process
  File "/builddir/build/BUILD/borgbackup-1.1.15/build/lib.linux-x86_64-3.10/borg/archiver.py", line 665 in _process
  File "/builddir/build/BUILD/borgbackup-1.1.15/build/lib.linux-x86_64-3.10/borg/archiver.py", line 665 in _process
  File "/builddir/build/BUILD/borgbackup-1.1.15/build/lib.linux-x86_64-3.10/borg/archiver.py", line 665 in _process
  File "/builddir/build/BUILD/borgbackup-1.1.15/build/lib.linux-x86_64-3.10/borg/archiver.py", line 551 in create_inner
  File "/builddir/build/BUILD/borgbackup-1.1.15/build/lib.linux-x86_64-3.10/borg/archiver.py", line 590 in do_create
  File "/builddir/build/BUILD/borgbackup-1.1.15/build/lib.linux-x86_64-3.10/borg/archiver.py", line 177 in wrapper
  File "/builddir/build/BUILD/borgbackup-1.1.15/build/lib.linux-x86_64-3.10/borg/archiver.py", line 4553 in run
  File "/builddir/build/BUILD/borgbackup-1.1.15/build/lib.linux-x86_64-3.10/borg/testsuite/archiver.py", line 110 in exec_cmd
  File "/builddir/build/BUILD/borgbackup-1.1.15/build/lib.linux-x86_64-3.10/borg/testsuite/archiver.py", line 290 in cmd
  File "/builddir/build/BUILD/borgbackup-1.1.15/build/lib.linux-x86_64-3.10/borg/testsuite/archiver.py", line 1241 in test_exclude_keep_tagged_deprecation
  File "/usr/lib64/python3.10/unittest/case.py", line 549 in _callTestMethod
  File "/usr/lib64/python3.10/unittest/case.py", line 592 in run
  File "/usr/lib64/python3.10/unittest/case.py", line 652 in __call__
  File "/usr/lib/python3.10/site-packages/_pytest/unittest.py", line 321 in runtest
  File "/usr/lib/python3.10/site-packages/_pytest/runner.py", line 162 in pytest_runtest_call
  File "/usr/lib/python3.10/site-packages/pluggy/callers.py", line 187 in _multicall
  File "/usr/lib/python3.10/site-packages/pluggy/manager.py", line 84 in <lambda>
  File "/usr/lib/python3.10/site-packages/pluggy/manager.py", line 93 in _hookexec
  File "/usr/lib/python3.10/site-packages/pluggy/hooks.py", line 286 in __call__
  File "/usr/lib/python3.10/site-packages/_pytest/runner.py", line 255 in <lambda>
  File "/usr/lib/python3.10/site-packages/_pytest/runner.py", line 311 in from_call
  File "/usr/lib/python3.10/site-packages/_pytest/runner.py", line 254 in call_runtest_hook
  File "/usr/lib/python3.10/site-packages/_pytest/runner.py", line 215 in call_and_report
  File "/usr/lib/python3.10/site-packages/_pytest/runner.py", line 126 in runtestprotocol
  File "/usr/lib/python3.10/site-packages/_pytest/runner.py", line 109 in pytest_runtest_protocol
  File "/usr/lib/python3.10/site-packages/pluggy/callers.py", line 187 in _multicall
  File "/usr/lib/python3.10/site-packages/pluggy/manager.py", line 84 in <lambda>
  File "/usr/lib/python3.10/site-packages/pluggy/manager.py", line 93 in _hookexec
  File "/usr/lib/python3.10/site-packages/pluggy/hooks.py", line 286 in __call__
  File "/usr/lib/python3.10/site-packages/_pytest/main.py", line 348 in pytest_runtestloop
  File "/usr/lib/python3.10/site-packages/pluggy/callers.py", line 187 in _multicall
  File "/usr/lib/python3.10/site-packages/pluggy/manager.py", line 84 in <lambda>
  File "/usr/lib/python3.10/site-packages/pluggy/manager.py", line 93 in _hookexec
  File "/usr/lib/python3.10/site-packages/pluggy/hooks.py", line 286 in __call__
  File "/usr/lib/python3.10/site-packages/_pytest/main.py", line 323 in _main
  File "/usr/lib/python3.10/site-packages/_pytest/main.py", line 269 in wrap_session
  File "/usr/lib/python3.10/site-packages/_pytest/main.py", line 316 in pytest_cmdline_main
  File "/usr/lib/python3.10/site-packages/pluggy/callers.py", line 187 in _multicall
  File "/usr/lib/python3.10/site-packages/pluggy/manager.py", line 84 in <lambda>
  File "/usr/lib/python3.10/site-packages/pluggy/manager.py", line 93 in _hookexec
  File "/usr/lib/python3.10/site-packages/pluggy/hooks.py", line 286 in __call__
  File "/usr/lib/python3.10/site-packages/_pytest/config/__init__.py", line 162 in main
  File "/usr/lib/python3.10/site-packages/_pytest/config/__init__.py", line 185 in console_main
  File "/usr/bin/py.test-3", line 33 in <module>

Extension modules: borg.hashindex, borg.algorithms.msgpack._packer, borg.algorithms.msgpack._unpacker, borg.crypto.low_level, borg.chunker, borg.item, borg.compress, borg.platform.posix, borg.platform.syncfilerange, borg.platform.linux, borg.algorithms.checksums, llfuse (total: 12)
/var/tmp/rpm-tmp.M1wJec: line 40:  1281 Segmentation fault      (core dumped) py.test-3 -x -vk "$TEST_SELECTOR" $PYTHONPATH/borg/testsuite/*.py
error: Bad exit status from /var/tmp/rpm-tmp.M1wJec (%check)

For the build logs, see:
https://copr-be.cloud.fedoraproject.org/results/@python/python3.10/fedora-rawhide-x86_64/02073213-borgbackup/

For all our attempts to build borgbackup with Python 3.10, see:
https://copr.fedorainfracloud.org/coprs/g/python/python3.10/package/borgbackup/

Testing and mass rebuild of packages is happening in copr. You can follow these instructions to test locally in mock if your package builds with Python 3.10:
https://copr.fedorainfracloud.org/coprs/g/python/python3.10/

Let us know here if you have any questions.

Python 3.10 will be included in Fedora 35. To make that update smoother, we're building Fedora packages with early pre-releases of Python 3.10.
A build failure prevents us from testing all dependent packages (transitive [Build]Requires), so if this package is required a lot, it's important for us to get it fixed soon.
We'd appreciate help from the people who know this package best, but if you don't want to work on this now, let us know so we can try to work around it on our side.