Re: [Sqlalchemy-tickets] [sqlalchemy] #2918: polymorphic aliasing failure when using trivial column subclass

[sqlalchemy <mi...@zz...>]

#2918: polymorphic aliasing failure when using trivial column subclass
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      Reporter:  zzzeek       |      Owner:  zzzeek
          Type:  defect       |     Status:  new
      Priority:  highest      |  Milestone:  0.9.xx
     Component:  orm          |   Severity:  major - 1-3 hours
    Resolution:               |   Keywords:
Progress State:  in progress  |
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Comment (by zzzeek):

 it's annotations, here's a test case:

 {{{
 #!python

 from sqlalchemy import Column

 class MySpecialColumn(Column):
     pass


 col = MySpecialColumn('x', String)
 binary_1 = col == 5   # caches col.comparator, col.comparator.expr == col
 c2 = col._annotate({"x": "foo"})   # uses Annotated, not AnnotatedColumn,
 as base class
 binary_2 = c2 == 5   # fails to use a new col.comparator, uses the old one
 with col and missing annotatinos
 }}}

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Ticket URL: <http://www.sqlalchemy.org/trac/ticket/2918#comment:1>
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