Thank you! That makes me feel quite a bit better. On Thursday, 6 May 2021 at 11:59:14 UTC-4 Mike Bayer wrote:
> the caching routine for datatypes is matching up the names of the > parameters to the internal state of the object. any name will reproduce > as long as you name the parameters and internal attributes the same. > > On Thu, May 6, 2021, at 11:52 AM, Steven James wrote: > > I originally came to that conclusion, and I agree that replacing it with a > tuple does fix it, but I still can't explain why using a different > parameter name also fixes it. > > On Thursday, 6 May 2021 at 11:46:53 UTC-4 Mike Bayer wrote: > > > this is a regression in SQLAlchemy in that the TypeDecorator is being > applied to caching without giving the end user any clue or API to control > this process. > > the name "choices" is not significant, it's that the parameter as given is > trying to be part of a cache key, so turn this into a tuple for now to > resolve: > > > class AltType(TypeDecorator): > impl = Unicode(255) > > def __init__(self, choices): > self.choices = tuple(choices) > super(AltType, self).__init__() > > > https://github.com/sqlalchemy/sqlalchemy/issues/6436 > > > > On Thu, May 6, 2021, at 11:08 AM, Steven James wrote: > > This one is baffling me. The following example throws an exception about > an unhashable type, related (I think) to the new query caching in 1.4. > However, if I change the parameter name to AltType.__init__ to ANYTHING > other than `choices`, it works fine. I can't find any reference to the name > `choices` in the sqlalchemy codebase. > > So why can't I use `choices` as a parameter name here? The answer might be > related to the AnnotatedColumn in the generated expression but that's about > as far as I've gotten. > > ``` > # sqlalchemy 1.4.x > > from sqlalchemy import Column, Integer, create_engine, TypeDecorator, > Unicode > from sqlalchemy.orm import sessionmaker, as_declarative, declared_attr > > > class AltType(TypeDecorator): > impl = Unicode(255) > > def __init__(self, choices): > self.choices = choices > super(AltType, self).__init__() > > > @as_declarative() > class Base(object): > @declared_attr > def __tablename__(cls): > return cls.__name__.lower() > > pk = Column(Integer, primary_key=True) > > > class MyClass(Base): > d = Column(AltType(['a', 'list', 'here'])) > > > if __name__ == '__main__': > e = create_engine('sqlite://', echo=True) > conn = e.connect() > > Base.metadata.create_all(e) > > s = sessionmaker(e)() > q = s.query(MyClass).filter(MyClass.d == 'search_str') > > result = q.first() # <---- error here > print(result) > > ``` > > result: > ``` > Traceback (most recent call last): > File "...\scratch_78.py", line 36, in <module> > results = q.first() > File "...\\lib\site-packages\sqlalchemy\orm\query.py", line 2750, in > first > return self.limit(1)._iter().first() > File "...\\lib\site-packages\sqlalchemy\orm\query.py", line 2834, in > _iter > result = self.session.execute( > File "...\\lib\site-packages\sqlalchemy\orm\session.py", line 1675, in > execute > result = conn._execute_20(statement, params or {}, execution_options) > File "...\\lib\site-packages\sqlalchemy\engine\base.py", line 1521, in > _execute_20 > return meth(self, args_10style, kwargs_10style, execution_options) > File "...\\lib\site-packages\sqlalchemy\sql\elements.py", line 313, in > _execute_on_connection > return connection._execute_clauseelement( > File "...\\lib\site-packages\sqlalchemy\engine\base.py", line 1382, in > _execute_clauseelement > compiled_sql, extracted_params, cache_hit = elem._compile_w_cache( > File "...\\lib\site-packages\sqlalchemy\sql\elements.py", line 531, in > _compile_w_cache > compiled_sql = compiled_cache.get(key) > File "...\\lib\site-packages\sqlalchemy\util\_collections.py", line 918, > in get > item = dict.get(self, key, default) > TypeError: unhashable type: 'list' > ``` > > -Steven James > > > -- > SQLAlchemy - > The Python SQL Toolkit and Object Relational Mapper > > http://www.sqlalchemy.org/ > > To post example code, please provide an MCVE: Minimal, Complete, and > Verifiable Example. See http://stackoverflow.com/help/mcve for a full > description. > --- > You received this message because you are subscribed to the Google Groups > "sqlalchemy" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to sqlalchemy+...@googlegroups.com. > To view this discussion on the web visit > https://groups.google.com/d/msgid/sqlalchemy/3e863503-4afa-44c3-b54a-4fb26ae5e8c8n%40googlegroups.com > > <https://groups.google.com/d/msgid/sqlalchemy/3e863503-4afa-44c3-b54a-4fb26ae5e8c8n%40googlegroups.com?utm_medium=email&utm_source=footer> > . > > > > -- > SQLAlchemy - > The Python SQL Toolkit and Object Relational Mapper > > http://www.sqlalchemy.org/ > > To post example code, please provide an MCVE: Minimal, Complete, and > Verifiable Example. See http://stackoverflow.com/help/mcve for a full > description. > --- > You received this message because you are subscribed to the Google Groups > "sqlalchemy" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to sqlalchemy+...@googlegroups.com. > > To view this discussion on the web visit > https://groups.google.com/d/msgid/sqlalchemy/e3e699b6-3b74-40b5-8213-58878ee23b8bn%40googlegroups.com > > <https://groups.google.com/d/msgid/sqlalchemy/e3e699b6-3b74-40b5-8213-58878ee23b8bn%40googlegroups.com?utm_medium=email&utm_source=footer> > . > > > -- SQLAlchemy - The Python SQL Toolkit and Object Relational Mapper http://www.sqlalchemy.org/ To post example code, please provide an MCVE: Minimal, Complete, and Verifiable Example. See http://stackoverflow.com/help/mcve for a full description. --- You received this message because you are subscribed to the Google Groups "sqlalchemy" group. 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