Is there any reason why HABTM default select clause is select * from ... rather than select table_name.* ... ? As it is attributes from the join table 'leak' into the attributes for the collection you are fetching (which for example makes a mess if you call to_xml on it). On the other hand has many through does do select table_name.*
Is there a specific legacy reason why this is so or is it just historical artificat (ie can we just change it to table_name.*)
Fred
This used to be a desired behavior; here's the note from the 1.1 changelog:
---- The method has been deprecated and removed for a while now, though.
Ah yes, that does make sense.
What attributes are "leaking" in your app? And how do you access them otherwise?
Not my app 
if you've got foo habtm bars then you get foo_id and bar_id attributes appearing, which you don't care about or ever want to access.
Fred
Frederick Cheung wrote:
---- The method has been deprecated and removed for a while now, though.
Ah yes, that does make sense.
Yeah, the behaviour has been 'frowned upon' for a while. Prior to the has_many through functionality it was a 'neat hack' for things like having created_at on some association.
Now it's kinda disgusting
Could be worth removing it for 2.3 now as it's just bound to cause confusion and people can manually do :select if they want it.
Makes sense to me. Anyone desperately holding onto this bit of functionality ?
Fred
It’s funny because the functionality is the only thing omitted from the email.
-Mike
Frederick Cheung wrote:
If you don't know what it is, you probably don't need it.
Basically if you have an additional column in the join table, its value will appear as a magic attribute on the retrieved records.