fileset #in_works method always returns []

[elrayle]

Description

When a fileset is in a work, calling method #in_works does not return the work.

Expected Results

in_works should return the work in an array

Actual Results

in_works returns an empty array

To reproduce

w1 = Hydra::Works::Work.new(id: 'w-1')
fs1 = Hydra::Works::FileSet.new(id: 'fs-1')
w1.members << fs1
w1.save

fs1.in_works  # => []
fs1.save
fs1.in_works  # => []

NOTE: If you create a collection and add w1 as a member, w1.in_collections will return an empty array until the collection is saved. In the code to reproduce, w1 is saved after putting fs1 into its member list.

[awead]

calling .ordered_members instead of .members fixes this. I'm not sure what the expectation is of the members method, but the tests indicated that ordered_members is the method to use:
https://github.com/projecthydra/hydra-works/blob/master/spec/hydra/works/models/file_set_spec.rb#L40-46

[elrayle]

Is .ordered_members the preferred method that should be encouraged over .members?

There are inconsistencies in the functioning of the in_* methods.

Examples assume
c1, c2 are collections
w1, w2 are works
fs1 is fileset
c1 and w1 are empty at the start of each set of statements

w1.members << fs1
w1.save
fs1.in_works   # => []

w1.ordered_members << fs1
w1.save
fs1.in_works   # =>    #<Work id: "w1" ... >

w1.members << w2
w1.save
w2.in_works   # => []

w1.ordered_members << w2
w1.save
w2.in_works   # =>   #<Work id: "w1" ... >

c1.members << c2
c1.save
c2.in_collections   # =>    #<Collection id: "c1" ... >

c1.ordered_members << c2
c1.save
c2.in_collections   # =>   #<Collection id: "c1" ... >

Why wouldn't the in_works and in_collections methods return all containing works and collections, respectively, whether the contained item was added with .members or .orderedmembers?

I would expect...

w1.members << w3
w2.ordered_members << w3
w3.in_works    # => #<Work id: "w1" ... >, #<Work id: "w2" ... >

[awead]

I would be in favor of deprecating the members method altogether since all members are ordered by default.

[tpendragon]

I would be in favor of deprecating the members method altogether since all members are ordered by default.

Not for collections. Ordering's moderately expensive, so when it's not needed it's important to have that option.

#in_works and #in_collections should probably work off members instead of ordered_members.

[elrayle]

It makes sense for #in_works and #in_collections to use members instead of ordered_members. When going from the contained to the containing items, order is not important.