"BackendUnavailable" error on install #374
Description
Using pip 20.2.2, Python 2.7.12, Ubuntu 16.04, virtual environment
pip install opencv-python==4.3.0.38
Same error with 3.4.10.37 - so maybe related to this? #46 (comment)
No error with 4.0.1.24
gives a BackendUnavailable error. This doesn't happen with other version of opencv installed in the same way inscluding 4.2.0
(aios-env) luke@AIDlaptop2:~/projects/AQC_CAS$ pip -V
pip 20.2.2 from /home/luke/projects/AQC_CAS/devel/aios-env/lib/python2.7/site-packages/pip (python 2.7)
(aios-env) luke@AIDlaptop2:~/projects/AQC_CAS$ pip install opencv-python==4.3.0.38
DEPRECATION: Python 2.7 reached the end of its life on January 1st, 2020. Please upgrade your Python as Python 2.7 is no longer maintained. pip 21.0 will drop support for Python 2.7 in January 2021. More details about Python 2 support in pip can be found at https://pip.pypa.io/en/latest/development/release-process/#python-2-support
Collecting opencv-python==4.3.0.38
Using cached opencv-python-4.3.0.38.tar.gz (88.0 MB)
Installing build dependencies ... done
Getting requirements to build wheel ... done
ERROR: Exception:
Traceback (most recent call last):
File "/home/luke/projects/AQC_CAS/devel/aios-env/lib/python2.7/site-packages/pip/_internal/cli/base_command.py", line 216, in _main
status = self.run(options, args)
File "/home/luke/projects/AQC_CAS/devel/aios-env/lib/python2.7/site-packages/pip/_internal/cli/req_command.py", line 182, in wrapper
return func(self, options, args)
File "/home/luke/projects/AQC_CAS/devel/aios-env/lib/python2.7/site-packages/pip/_internal/commands/install.py", line 325, in run
reqs, check_supported_wheels=not options.target_dir
File "/home/luke/projects/AQC_CAS/devel/aios-env/lib/python2.7/site-packages/pip/_internal/resolution/legacy/resolver.py", line 183, in resolve
discovered_reqs.extend(self._resolve_one(requirement_set, req))
File "/home/luke/projects/AQC_CAS/devel/aios-env/lib/python2.7/site-packages/pip/_internal/resolution/legacy/resolver.py", line 388, in _resolve_one
abstract_dist = self._get_abstract_dist_for(req_to_install)
File "/home/luke/projects/AQC_CAS/devel/aios-env/lib/python2.7/site-packages/pip/_internal/resolution/legacy/resolver.py", line 340, in _get_abstract_dist_for
abstract_dist = self.preparer.prepare_linked_requirement(req)
File "/home/luke/projects/AQC_CAS/devel/aios-env/lib/python2.7/site-packages/pip/_internal/operations/prepare.py", line 483, in prepare_linked_requirement
req, self.req_tracker, self.finder, self.build_isolation,
File "/home/luke/projects/AQC_CAS/devel/aios-env/lib/python2.7/site-packages/pip/_internal/operations/prepare.py", line 91, in _get_prepared_distribution
abstract_dist.prepare_distribution_metadata(finder, build_isolation)
File "/home/luke/projects/AQC_CAS/devel/aios-env/lib/python2.7/site-packages/pip/_internal/distributions/sdist.py", line 38, in prepare_distribution_metadata
self._setup_isolation(finder)
File "/home/luke/projects/AQC_CAS/devel/aios-env/lib/python2.7/site-packages/pip/_internal/distributions/sdist.py", line 96, in _setup_isolation
reqs = backend.get_requires_for_build_wheel()
File "/home/luke/projects/AQC_CAS/devel/aios-env/lib/python2.7/site-packages/pip/_vendor/pep517/wrappers.py", line 161, in get_requires_for_build_wheel
'config_settings': config_settings
File "/home/luke/projects/AQC_CAS/devel/aios-env/lib/python2.7/site-packages/pip/_vendor/pep517/wrappers.py", line 265, in _call_hook
raise BackendUnavailable(data.get('traceback', ''))
BackendUnavailable