Hi there,
After implementing the solutions for raising on column usages brought up at
https://groups.google.com/forum/#!topic/sqlalchemy/Lbyq8Co95mQ, I've come
across an issue where a deferred column is being loaded by default after a
series of function calls. Here's the minimal repro I could find:
class MyColumn(Column):
pass
@compiles(MyColumn)
def compile_column(element, compiler, **kw):
raise Exception('compile_column')
class MyTable():
id = Column(Integer, primary_key=True)
deferred_column = deferred(MyColumn(...))
from sqlalchemy.orm.session import make_transient, make_transient_to_detached
item = MyTable.query.first() # doesn't load deferred_column
make_transient(item)
make_transient_to_detached(item)
db.session.add(item)
db.session.expire_all()
item.id # Ordinarily, loading item.id should not be accessing deferred_column
> Exception: compile_column
It looks like it's hitting this line:
https://github.com/zzzeek/sqlalchemy/blob/887fb3ebaad20847edc752f5fcf072ace947d56a/lib/sqlalchemy/orm/loading.py#L797,
which seems to be where the column is getting undeferred — is this behavior
intentional? (There also may be a simpler way to reproduce this behavior.)
If it is intentional, is there anyway to work around this so the column
isn't loaded in?
(In case it helps, we use make_transient and make_transient_to_detached for
tests to ensure each test starts in the same session state even while using
nested transactions).
Thank you!
Neena
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