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| author | Mike Bayer <mike_mp@zzzcomputing.com> | 2018-06-01 16:54:11 -0500 |
|---|---|---|
| committer | Mike Bayer <mike_mp@zzzcomputing.com> | 2018-06-04 11:42:49 -0400 |
| commit | 5628da627c4f248a817eafd72ecdf4793809f68d (patch) | |
| tree | f3fb07bce5108345e2ff7ca8776271205def7100 /lib/sqlalchemy/orm | |
| parent | 45b22c9c3fd8fc0d2c80ec00ef9070837cd18063 (diff) | |
| download | sqlalchemy-5628da627c4f248a817eafd72ecdf4793809f68d.tar.gz | |
Support undocumented non-entity sequence Query argument
Fixed regression caused by :ticket:`4256` (itself a regression fix for
:ticket:`4228`) which breaks an undocumented behavior which converted for a
non-sequence of entities passed directly to the :class:`.Query` constructor
into a single-element sequence. While this behavior was never supported or
documented, it's already in use so has been added as a behavioral contract
to :class:`.Query`.
Change-Id: I97546f5ab5af29f37c86321f39d564f98a12daf5
Fixes: #4269
Diffstat (limited to 'lib/sqlalchemy/orm')
| -rw-r--r-- | lib/sqlalchemy/orm/query.py | 22 |
1 files changed, 21 insertions, 1 deletions
diff --git a/lib/sqlalchemy/orm/query.py b/lib/sqlalchemy/orm/query.py index 56e42a702..8f6042a2b 100644 --- a/lib/sqlalchemy/orm/query.py +++ b/lib/sqlalchemy/orm/query.py @@ -147,7 +147,27 @@ class Query(object): self._entities = [] self._primary_entity = None self._has_mapper_entities = False - if entities: + + # 1. don't run util.to_list() or _set_entity_selectables + # if no entities were passed - major performance bottleneck + # from lazy loader implementation when it seeks to use Query + # class for an identity lookup, causes test_orm.py to fail + # with thousands of extra function calls, see issue #4228 + # for why this use had to be added + # 2. can't use classmethod on Query because session.query_cls + # is an arbitrary callable in some user recipes, not + # necessarily a class, so we don't have the class available. + # see issue #4256 + # 3. can't do "if entities is not None" because we usually get here + # from session.query() which takes in *entities. + # 4. can't do "if entities" because users make use of undocumented + # to_list() behavior here and they pass clause expressions that + # can't be evaluated as boolean. See issue #4269. + # 5. the empty tuple is a singleton in cPython, take advantage of this + # so that we can skip for the empty "*entities" case without using + # any Python overloadable operators. + # + if entities is not (): for ent in util.to_list(entities): entity_wrapper(self, ent) |