Packages containing pytest tests create conflicting cache files

[nuclearsandwich]

Example log output from the build of ament_copyright (although the problem is found in ament_lint 0.16.3-noble and ament_pep257 0.16.3-noble which are both test dependencies of ament_copyright.

08:32:47   655 'Selecting previously unselected package ros-rolling-ros-workspace.'
08:32:47   656 'Preparing to unpack .../137-ros-rolling-ros-workspace_1.0.3-5noble.20240308.162208_amd64.deb ...'
08:32:47   657 'Unpacking ros-rolling-ros-workspace (1.0.3-5noble.20240308.162208) ...'
08:32:47   658 'Selecting previously unselected package ros-rolling-ament-lint.'
08:32:47   659 'Preparing to unpack .../138-ros-rolling-ament-lint_0.16.3-2noble.20240308.162603_amd64.deb ...'
08:32:47   660 'Unpacking ros-rolling-ament-lint (0.16.3-2noble.20240308.162603) ...'
08:32:47   661 'Selecting previously unselected package ros-rolling-ament-flake8.'
08:32:47   662 'Preparing to unpack .../139-ros-rolling-ament-flake8_0.16.3-2noble.20240308.162704_amd64.deb ...'
08:32:47   663 'Unpacking ros-rolling-ament-flake8 (0.16.3-2noble.20240308.162704) ...'
08:32:47   664 'Selecting previously unselected package ros-rolling-ament-pep257.'
08:32:47   665 'Preparing to unpack .../140-ros-rolling-ament-pep257_0.16.3-2noble.20240308.162849_amd64.deb ...'
08:32:47   666 'Unpacking ros-rolling-ament-pep257 (0.16.3-2noble.20240308.162849) ...'
08:32:47   667 'dpkg: error processing archive /tmp/apt-dpkg-install-R3A0tO/140-ros-rolling-ament-pep257_0.16.3-2noble.20240308.162849_amd64.deb (--unpack):'
08:32:47   668 ' trying to overwrite '/opt/ros/rolling/lib/python3.12/site-packages/.pytest_cache/.gitignore', which is also in package ros-rolling-ament-lint 0.16.3-2noble.20240308.162603'
08:32:47   669 'Errors were encountered while processing:'
08:32:47   670 ' /tmp/apt-dpkg-install-R3A0tO/140-ros-rolling-ament-pep257_0.16.3-2noble.20240308.162849_amd64.deb'
08:32:47   671 'W: Target Packages (multiverse/binary-amd64/Packages) is configured multiple times in /etc/apt/sources.list:5 and /etc/apt/sources.list.d/ubuntu.sources:1'
08:32:47   672 'W: Target Packages (multiverse/binary-all/Packages) is configured multiple times in /etc/apt/sources.list:5 and /etc/apt/sources.list.d/ubuntu.sources:1'
08:32:47   673 'W: Target Packages (multiverse/binary-amd64/Packages) is configured multiple times in /etc/apt/sources.list:7 and /etc/apt/sources.list.d/ubuntu.sources:1'
08:32:47   674 'W: Target Packages (multiverse/binary-all/Packages) is configured multiple times in /etc/apt/sources.list:7 and /etc/apt/sources.list.d/ubuntu.sources:1'
08:32:47   675 'E: Sub-process /usr/bin/dpkg returned an error code (1)'

This is being mitigated on our build farm by turning off the execution of tests and the installation of test dependencies before triggering a rebuild, which should omit these cache files from our builds but there are ways for us the cache location generally or else exclude these files from packaging as a more complete solution.

[Z572]

add PYTEST_ADDOPTS: '-pno:cacheprovider' to build_environment_variables can fix it.