set_count_on_hand should use lock just like adjust_count_on_hand

[jrochkind]

No idea how to write a test for this. But if adjust_count_on_hand, right
above this method, needs a db lock to avoid race conditions -- then surely
set_count_on_hand does too, no?

Or if neither does, that's a different PR.

[jrochkind]

Or perhaps adjust_count_on_hand should actually be written in terms of set_count_on_hand?

[jrochkind]

Here's the failure from circleci:

  1) Spree::StockItem#after_save inventory_cache_threshold is set count on hand stays above threshold
     Failure/Error:
       expect do
         subject.set_count_on_hand(8)
       end.not_to change { subject.variant.updated_at }

       expected result not to have changed, but did change from 2016-04-24 20:20:41.258599812 +0000 to 2016-04-24 20:20:41.258599000 +0000
     # ./spec/models/spree/stock_item_spec.rb:223:in `block (4 levels) in <top (required)>'

Huh? Anyone have an idea what's going on? How does no change but adding a db lock to guard against race conditions result in a variant getting it's updated_at touched when it wasn't before?

Any ideas?

[peterberkenbosch]

not sure either how you could explicitly test this, I think this change should just keep the existing specs green. I cherry-picked your commit in a local branch based of master and the specs are green now. Will submit a new PR with your commit in a sec.

[jrochkind]

Thanks so much @peterberkenbosch !

[tvdeyen]

Closing as stale. Please reopen if you think this is still something we should to tackle.

[bbuchalter]

I think this is an important change that we need to continue working at, but I don't know how to move this forward.