Problem: pre-flight check errors when there is an upgraded pip

in a system-wide venv

and when the package is installed as an RPM in the prereq role
at an acceptable version, so the pre-flight check should not
have tried to use a newer version from PyPI.

This is a regression from #6645. Previously many errors were ignored,
this error should still be ignored too until system-wide packages
support is removed.

fixes: #6690
pre-flight check errors when there is an upgraded pip in a system-wide venv
https://pulp.plan.io/issues/6690

re: #6645
pre-flight check does not work properly when it needs a prereq role
https://pulp.plan.io/issues/6645

CHANGES/6690.bugfix

@@ -0,0 +1 @@
+Fixed pre-flight check producing an error (and accidentally enforcing) when trying & failing to build certain packages from PyPI that are actually available as a system-wide (RPM/deb-installed) package in the virtualenv. This issue was never present on the previous release, only on the develoment branch.

roles/pulp/tasks/install.yml

@@ -224,6 +224,10 @@
     - name: Re-run pre-flight check after plugin prereq roles
       include_tasks: preflight_function.yml
       # if it didn't succeed last time
+      vars:
+        failed_condition: >
+          (compatibility.rc != 0) and
+          ("AttributeError: module \'setuptools.build_meta\' has no attribute \'__legacy__\'" not in compatibility.stderr)
       when:
         - pulp_source_dir is undefined
         - compatibility is defined