[Sqlalchemy-tickets] Issue #4179: table.tometadata(...) doesn't copy event handlers (zzzeek/sqlalchemy)

[Chris W. <iss...@bi...>]

New issue 4179: table.tometadata(...) doesn't copy event handlers
https://bitbucket.org/zzzeek/sqlalchemy/issues/4179/tabletometadata-doesnt-copy-event-handlers

Chris Withers:

I added some custom DDL to a table definition as follows:


```
#!python

event.listen(
    Observation.__table__,
    'after_create',
    DDL(
        'alter table observation add constraint observation_best ...'
    )
)
```

...but it wasn't firing, not even an exception when I deliberately misspelled the table name ;-)

Tracked it down to this class I use to allow one schema to be managed by multiple python packages:

https://github.com/Mortar/mortar_rdb/blob/master/mortar_rdb/controlled.py#L59

This line in particular:

https://github.com/Mortar/mortar_rdb/blob/master/mortar_rdb/controlled.py#L81

It appears that call isn't carrying the event handlers across to the table created in the new metadata object. For my use case, it needs to, but I appreciate my use case may well be a bit of an edge case.