Hi All,
Recently, in the AR AsscociationProxy class, my colleague and I came
across a case that seems to be a violation of the principle of least
surprise.
The problem shows itself when trying to take out an elevated lock on
an ActiveRecord#Base object: 'ar_obj.reload(:lock => true)'. In
general, this works fine. However, if the ar_obj object was not
created directly, but instead came from an association proxy off some
other AR#base object, then we have a problem. Since AssociationProxy
defines its own (no-arg) version of #reload we hit a "wrong number of
arguments error" because the object we're calling the method on is of
type AssociationProxy, not AR:Base. Thank the stars that the AP#reload
method doesn't take an options hash, if that were the case it could be
possible to go forward thinking the object was having its lock
elevated as expected. With the problem understood it was easy enough
to work around by checking if the object had a #target method and
using that target object directly if it did.
So, long story short, the implementation of AssociationProxy exposes
itself when using the #reload(:lock => true) technique to elevate a
lock. My question to the core is whether or not this is an acceptable
side effect of the implementation? In particular, I am curious if
using this #reload method of lock escalation is a supported mode of
operation, or is there some other means to the same end that is better
supported by ActiveRecord? For instance, I suppose I could do this
(hopefully the formatting on this doesn't get bojacked):
<pre>
def do_stuff_with_lock(ar_or_ap_object)
transaction do
ar_or_ap_object.class.find(ar_or_ap_object.id, :lock => true)
# do stuff with ar_or_ap_object
ar_or_ap_object.save
end
end
</pre>
Cheers,
Andrew
--~--~---------~--~----~------------~-------~--~----~
You received this message because you are subscribed to the Google Groups "Ruby
on Rails: Core" group.
To post to this group, send email to [email protected]
To unsubscribe from this group, send email to [EMAIL PROTECTED]
For more options, visit this group at
http://groups.google.com/group/rubyonrails-core?hl=en
-~----------~----~----~----~------~----~------~--~---
