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Mike Bayer
93dc7ea150
The ``aliased()`` constructor calls upon ``__clause_element__()``, which internally annotates a ``FromClause``, like a subquery. This became expensive as ``AnnotatedFromClause`` has for many years called upon ``element.c`` so that the full ``.c`` collection is transferred to the Annotated. Taking this out proved to be challenging. A straight remove seemed to not break any tests except for the one that tested the exact condition. Nevertheless this seemed "spooky" so I instead moved the get of ``.c`` to be in a memoized proxy method. However, that then exposed a recursion issue related to loader_criteria; so the source of that behavior, which was an accidental behavioral artifact, is now made into an explcicit option that loader_criteria uses directly. The accidental behavioral artifact in question is still kind of strange since I was not able to fully trace out how it works, but the end result is that fixing the artifact to be "correct" causes loader_criteria, within the particular test for #7491, creates a select/ subquery structure with a cycle in it, so compilation fails with recursion overflow. The "solution" is to cause the artifact to occur in this case, which is that the ``AnnotatedFromClause`` will have a different ``.c`` collection than its element, which is a subquery. It's not totally clear how a cycle is generated when this is not done. This is commit one of two, which goes through some hoops to make essentially a one-line change. The next commit will rework ColumnCollection to optimize the corresponding_column() method significantly. Fixes: #8796 Change-Id: Id58ae6554db62139462c11a8be7313a3677456ad