#2425 [PATCH] Add methods on active record to denote whether any associated objects exist for that association - Ruby on Rails

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#2425 ✓wontfix

[PATCH] Add methods on active record to denote whether any associated objects exist for that association

Reported by avijayr (at gmail) | April 5th, 2009 @ 08:48 PM

hi, In many of my projects that deal with serializing an active record (usually to xml), we have to evaluate whether associated objects exist or not. If they do exist, then a separate call is made to fetch the associated objects (usually in a paged scenario). Rather than define the Proc inside the to_xml method, it would be better if the method is defined automatically in the AssociationReflection class. This patch will define a method with the question mark, and another to be used for the xml serialization.

adding_has_associated_obj_exist.diff 2.8 KB

Comments and changes to this ticket

CancelProfileIsBroken August 6th, 2009 @ 01:00 PM
- Tag set to “bugmash”
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pjammer August 8th, 2009 @ 06:40 PM
+1 patch verified and all tests pass.

It appears that this method would be very handy, when needed.
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Nick Quaranto August 8th, 2009 @ 06:58 PM
-1, I don't like the alias_method to has_#{name} and it seems that keeping a similar api to the dirty methods would be better. For example, if a Post has many Comments:
```
post = Post.new
post.comments?
```
instead of
```
post = Post.new
post.has_comments?
```
would be a lot cleaner.
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Josh Nichols August 8th, 2009 @ 07:00 PM
+1 on the feature, -1 on the implementation.

I agree with Nick on excluding has for the methods, ie comments? instead of has_comments?. This would be more in line with what you get from normal attributes.
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Josh Susser August 8th, 2009 @ 07:26 PM
I think post.comments.any? is a more consistent API. IMO it's better to keep the number of generated methods on the base class to a minimum, and layer this kind of behavior onto the association proxy object.
Dan Pickett August 8th, 2009 @ 07:27 PM
-1 on the implementation

I agree with Nick on this as well.

note that #49 was similar and denied - although this has more to do with verifying that the collection is empty or object exists
Jeremy Kemper August 8th, 2009 @ 10:36 PM
- State changed from “new” to “wontfix”
Enumerable's already got the goods here, so let's not introduce a new overlapping API that only works with AR assocations.
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Elad Meidar August 8th, 2009 @ 10:45 PM
Here's a patch for 2-3-stable removing the has_#{name} methods and keeps only the #{name}? methods.
- no_has_empty_denotation_for_ar_associations_2-3-stable.diff 2.5 KB
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Elad Meidar August 8th, 2009 @ 10:46 PM
forgot to mention that the patch is applied on master too.
Rizwan Reza August 8th, 2009 @ 10:51 PM
verified.

+1 Patch works perfectly in master.
CancelProfileIsBroken August 8th, 2009 @ 11:08 PM
- Tag cleared.
- Milestone cleared.
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avijayr (at gmail) August 9th, 2009 @ 01:36 AM
I would like to point out two things:
1) The usage scenario described was for serialization to xml so that a corresponding ActiveResource could then be queried in a simple(shallow?) way before making a nested call. That is the reason why the implementation has the 'has_'. In the context of a ARecord, the method with '?' makes sense (to be compatible with Rails' notion of asking a question), but when you want to serialize the same, in my case in the to_xml method on ARecord, the '?' has to be treated specially - which is why I provided an alias without the '?'.

As far as the presence of the 'has_' - this is present to differentiate between the query to retrieve the associated objects vs the presence of these associated objects.

I hope I made myself clear as to why the implementation was the way it was.