[Sqlalchemy-tickets] [sqlalchemy] #2775: bulk update/delete events / invent new system for changing event arguments

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

#2775: bulk update/delete events / invent new system for changing event arguments
-------------------------+------------------------------------
 Reporter:  zzzeek       |           Owner:  zzzeek
     Type:  enhancement  |          Status:  new
 Priority:  medium       |       Milestone:  0.9.0
Component:  orm          |        Severity:  major - 1-3 hours
 Keywords:               |  Progress State:  in queue
-------------------------+------------------------------------
 the bulk UD events should have access to the arguments that were passed:

 {{{
 #!python
 def after_bulk_update(self, session, query, query_context, values,
 synchronize_session, result):
    ""
 }}}

 and while we're at it, mapper events should get some more context too:

 {{{
 #!python
     def before_insert(self, session, flush_context, mapper, connection,
 target):
          ""
 }}}

 how can we pull this off?   we'd need to build a really smart argument
 adapter that uses inspect:


 {{{
 #!python
 @event.legacy_signature("0.9", ["session", "query", "query_context",
 "result"])
 def after_bulk_update(self, session, query, query_context, values,
 synchronize_session, result):
    ""
 }}}

 legacy_signature would need to receive the decorated fn, use inspect to
 look at how many arguments it accepts, then produce a translation wrapper
 corresponding to the given signature.   it should even stick a
 "..versionchanged::" directive into the docstring.

 another issue, these events take a crapload of arguments.  How do we deal
 with that?   Let's support this too:

 {{{
 #!python
 @event.listens_for(Session, "after_bulk_update")
 def after_update(self, **kw):
 }}}

 with the above signature the event system will detect that, and just send
 all args in as key/value pairs, so that event handlers can be written more
 simply just to look for what they need.

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Ticket URL: <http://www.sqlalchemy.org/trac/ticket/2775>
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