[rset] fix infinite recursion introduced in c1eb5a676c80
The mechanism to avoid loops in c1eb5a676c80 "[rset] Always complete
attribute/relation caches in ResultSet.get_entity" breaks down: we would
loop forever if two entities that were already in the cache were linked
by a relation with ? or 1 cardinality in both directions. To avoid
that, keep a set of already-considered columns. Related to #9942503.
usr/lib/python2*/*-packages/cubicweb/devtools/
usr/lib/python2*/*-packages/cubicweb/skeleton/
usr/lib/python2*/*-packages/cubicweb/test
usr/lib/python2*/*-packages/cubicweb/dataimport/test
usr/lib/python2*/*-packages/cubicweb/entities/test
usr/lib/python2*/*-packages/cubicweb/ext/test
usr/lib/python2*/*-packages/cubicweb/server/test
usr/lib/python2*/*-packages/cubicweb/sobjects/test
usr/lib/python2*/*-packages/cubicweb/hooks/test
usr/lib/python2*/*-packages/cubicweb/web/test
usr/lib/python2*/*-packages/cubicweb/etwist/test