view roundup/anypy/cmp_.py @ 6433:c1d3fbcdbfbd

issue2551142 - Import of retired node ... unique constraint failure. Title: Import of retired node with username after active node fails with unique constraint failure. More fixes needed for mysql and postgresql. mysql: add unique constraint for (keyvalue, __retired__) when creating class in the database. On schema change if class is changed, remove the unique constraint too. upgrade version of rdbms database from 5 to 6 to add constraint to all version 5 databases that were created as version 5 and didn't get the unique constraint. Make no changes on version 5 databases upgraded from version 4, the upgrade process to 5 added the constraint. Make no changes to other databases (sqlite, postgres) during upgrade from version 5 to 6. postgres: Handle the exception raised on unique constraint violation. The exception invalidates the database connection so it can't be used to recover from the exception. Added two new database methods: checkpoint_data - performs a db.commit under postgres does nothing on other backends restore_connection_on_error - does a db.rollback on postgres, does nothing on other backends with the rollback() done on the connection I can use the database connection to fixup the import that failed on the unique constraint. This makes postgres slower but without the commit after every imported object, the rollback will delete all the entries done up to this point. Trying to figure out how to make the caller do_import batch and recover from this failure is beyond me. Also dismissed having to process the export csv file before importing. Pushing that onto a user just seems wrong. Also since import/export isn't frequently done the lack of surprise on having a failing import and reduced load/frustration for the user seems worth it. Also the import can be run in verbose mode where it prints out a row as it is processed, so it may take a while, ut the user can get feedback. db_test-base.py: add test for upgrade from 5 to 6.
author John Rouillard <rouilj@ieee.org>
date Thu, 10 Jun 2021 12:52:05 -0400
parents 142553f58694
children 706f3be6ffbb
line wrap: on
line source

try:
    None < 0

    def NoneAndDictComparable(v):
        return v
except TypeError:
    # comparator to allow comparisons against None and dict
    # comparisons (these were allowed in Python 2, but aren't allowed
    # in Python 3 any more)
    class NoneAndDictComparable(object):
        def __init__(self, value):
            self.value = value

        def __cmp__(self, other):
            if not isinstance(other, self.__class__):
                raise TypeError('not comparable')

            if self.value == other.value:
                return 0

            elif self.value is None:
                return -1

            elif other.value is None:
                return 1

            elif type(self.value) == tuple and type(other.value) == tuple:
                for lhs, rhs in zip(self.value, other.value):
                    lhsCmp = NoneAndDictComparable(lhs)
                    rhsCmp = NoneAndDictComparable(rhs)
                    result = lhsCmp.__cmp__(rhsCmp)
                    if result != 0:
                        return result

                return len(self.value) - len(other.value)

            elif type(self.value) == dict and type(other.value) == dict:
                diff = len(self.value) - len(other.value)
                if diff == 0:
                    lhsItems = tuple(sorted(self.value.items(),
                                            key=NoneAndDictComparable))
                    rhsItems = tuple(sorted(other.value.items(),
                                            key=NoneAndDictComparable))
                    return -1 if NoneAndDictComparable(lhsItems) < NoneAndDictComparable(rhsItems) else 1
                else:
                    return diff

            elif self.value < other.value:
                return -1

            else:
                return 1

        def __eq__(self, other):
            return self.__cmp__(other) == 0

        def __ne__(self, other):
            return self.__cmp__(other) != 0

        def __lt__(self, other):
            return self.__cmp__(other) < 0

        def __le__(self, other):
            return self.__cmp__(other) <= 0

        def __ge__(self, other):
            return self.__cmp__(other) >= 0

        def __gt__(self, other):
            return self.__cmp__(other) > 0


def _test():
    Comp = NoneAndDictComparable

    assert Comp(None) < Comp(0)
    assert Comp(None) < Comp('')
    assert Comp(None) < Comp({})
    assert Comp((0, None)) < Comp((0, 0))
    assert not Comp(0) < Comp(None)
    assert not Comp('') < Comp(None)
    assert not Comp({}) < Comp(None)
    assert not Comp((0, 0)) < Comp((0, None))

    assert Comp((0, 0)) < Comp((0, 0, None))
    assert Comp((0, None, None)) < Comp((0, 0, 0))

    assert Comp(0) < Comp(1)
    assert Comp(1) > Comp(0)
    assert not Comp(1) < Comp(0)
    assert not Comp(0) > Comp(0)

    assert Comp({0: None}) < Comp({0: 0})
    assert Comp({0: 0}) < Comp({0: 1})

    assert Comp({0: 0}) == Comp({0: 0})
    assert Comp({0: 0}) != Comp({0: 1})
    assert Comp({0: 0, 1: 1}) > Comp({0: 1})
    assert Comp({0: 0, 1: 1}) < Comp({0: 0, 2: 2})


if __name__ == '__main__':
    _test()

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