Log Message:
py-sqlalchemy: updated to 1.3.4

1.3.4

orm
[orm] [bug]
Fixed issue where the AttributeEvents.active_history flag would not be set for \ 
an event listener that propgated to a subclass via the AttributeEvents.propagate \ 
flag. This bug has been present for the full span of the AttributeEvents system.

[orm] [bug]
Fixed regression where new association proxy system was still not proxying \ 
hybrid attributes when they made use of the @hybrid_property.expression \ 
decorator to return an alternate SQL expression, or when the hybrid returned an \ 
arbitrary PropComparator, at the expression level. This involved futher \ 
generalization of the heuristics used to detect the type of object being proxied \ 
at the level of QueryableAttribute, to better detect if the descriptor \ 
ultimately serves mapped classes or column expressions.

[orm] [bug]
Applied the mapper “configure mutex” against the declarative class mapping \ 
process, to guard against the race which can occur if mappers are used while \ 
dynamic module import schemes are still in the process of configuring mappers \ 
for related classes. This does not guard against all possible race conditions, \ 
such as if the concurrent import has not yet encountered the dependent classes \ 
as of yet, however it guards against as much as possible within the SQLAlchemy \ 
declarative process.

[orm] [bug]
A warning is now emitted for the case where a transient object is being merged \ 
into the session with Session.merge() when that object is already transient in \ 
the Session. This warns for the case where the object would normally be \ 
double-inserted.

[orm] [bug]
Fixed regression in new relationship m2o comparison logic first introduced at \ 
Improvement to the behavior of many-to-one query expressions when comparing to \ 
an attribute that is persisted as NULL and is in an un-fetched state in the \ 
mapped instance. Since the attribute has no explicit default, it needs to \ 
default to NULL when accessed in a persistent setting.

engine
[engine] [bug] [postgresql]
Moved the “rollback” which occurs during dialect initialization so that it \ 
occurs after additional dialect-specific initialize steps, in particular those \ 
of the psycopg2 dialect which would inadvertently leave transactional state on \ 
the first new connection, which could interfere with some psycopg2-specific APIs \ 
which require that no transaction is started. Pull request courtesy Matthew \ 
Wilkes.

sql
[sql] [bug]
Fixed that the GenericFunction class was inadvertently registering itself as one \ 
of the named functions. Pull request courtesy Adrien Berchet.

[sql] [bug]
Fixed issue where double negation of a boolean column wouldn’t reset the \ 
“NOT” operator.

[sql] [bug]
The GenericFunction namespace is being migrated so that function names are \ 
looked up in a case-insensitive manner, as SQL functions do not collide on case \ 
sensitive differences nor is this something which would occur with user-defined \ 
functions or stored procedures. Lookups for functions declared with \ 
GenericFunction now use a case insensitive scheme, however a deprecation case is \ 
supported which allows two or more GenericFunction objects with the same name of \ 
different cases to exist, which will cause case sensitive lookups to occur for \ 
that particular name, while emitting a warning at function registration time. \ 
Thanks to Adrien Berchet for a lot of work on this complicated feature.

postgresql
[postgresql] [bug] [orm]
Fixed an issue where the “number of rows matched” warning would emit even if \ 
the dialect reported “supports_sane_multi_rowcount=False”, as is the case \ 
for psycogp2 with use_batch_mode=True and others.

mysql
[mysql] [bug]
Added support for DROP CHECK constraint which is required by MySQL 8.0.16 to \ 
drop a CHECK constraint; MariaDB supports plain DROP CONSTRAINT. The logic \ 
distinguishes between the two syntaxes by checking the server version string for \ 
MariaDB presence. Alembic migrations has already worked around this issue by \ 
implementing its own DROP for MySQL / MariaDB CHECK constraints, however this \ 
change implements it straight in Core so that its available for general use. \ 
Pull request courtesy Hannes Hansen.

mssql
[mssql] [feature]
Added support for SQL Server filtered indexes, via the mssql_where parameter \ 
which works similarly to that of the postgresql_where index function in the \ 
PostgreSQL dialect.

[mssql] [bug]
Added error code 20047 to “is_disconnect” for pymssql. Pull request courtesy \ 
Jon Schuff.

misc
[misc] [bug]
Removed errant “sqla_nose.py” symbol from MANIFEST.in which created an \ 
undesirable warning message.