primary key change within a savepoint block would not
participate in being restored to their former state (not in
session, in session, previous PK) after the outer transaction
were rolled back. fixes #3108

as the attribute and probably just replaced itself, so that is
now _set_enable_single_crit
- as a side effect of the main issue fixed here, correct the case in
adjust_for_single_inheritance where the same mapper appears more
than once in mapper_adapter_map; run through a set() for uniqueness.
- Fixed bug in subquery eager loading in conjunction with
:func:`.with_polymorphic`, the targeting of entities and columns
in the subquery load has been made more accurate with respect
to this type of entity and others. Fixes #3106

of :ticket:`3060` from verision 0.9.5.  A self-referential relationship
with lazy='dynamic' would raise a TypeError within a flush operation.
fixes #3099

when we do a get; we return the None as always but we leave the dict blank
and the loader callable still in place.  The case for this implicit get on a pending object is not
super common and there really should be no change in state at all when this
operation proceeds.   This change is more dramatic as it reverses
a behavior SQLA has had since the first release.
fixes #3061

fix that is updated more comprehensively in 1.0 via :ticket:`3061`.
The fix in :ticket:`3060` unfortunately produces a new issue whereby
an eager load of a many-to-one attribute can produce an event
that is interpreted into an attribute change.

based on hash ordering of the ClassManager

mapper is implicitly combining one of its column-based attributes
with that of the parent, where those columns normally don't necessarily
share the same value.  This is an extension of an existing check that
was added via :ticket:`1892`; however this new check emits only a
warning, instead of an exception, to allow for applications that may
be relying upon the existing behavior.
fixes #3042

columns are always added to the list of columns to be "undeferred";
otherwise, the ORM can't load the row's identity.   Apparently,
one can defer the mapped primary keys and the ORM will fail, that
hasn't been changed.  But as load_only is essentially saying
"defer all but X", it's more critical that PK cols not be part of this
deferral. fixes #3080

of work such that loading for related many-to-one objects is slightly
more aggressive, in the case of a graph of self-referential objects
that are to be deleted; the load of related objects is to help
determine the correct order for deletion if passive_deletes is
not set.
- revert the changes to test_delete_unloaded_m2o, these deletes do in fact
need to occur in the order of the two child objects first.