Don't save mass_action event to db when saving stock item model

[bob2021]

This is part of a group of PRs containing the changes discussed in issue #152

When a stock item model is saved independently of a product model (eg. during checkout) and 'Display Out of Stock Products' = 'No', the following happens:

• A mass_action index event is registered
• The stock indexer runs
• The mass_action event from earlier is processed; these indexers run:
  • catalog_product_attribute
  • catalog_product_price
  • catalogsearch_fulltext

The problems are:

• Saving a mass_action event just to load it later on in the same request is inefficient
• The mass_action event isn't actually required unless the stock status has changed
• One mass_action record is shared between all requests:
  • If indexers are set to manual mode the event data can grow very large (megabytes)
  • When the event is loaded it could contain data from other requests; events could be processed more than once across different requests

This PR has been updated since I initially opened it, the original approach had the advantage that it indexed everything in one pass, but it was more complex and less backwards compatible. The original is here.

This PR keeps the mass_action event in memory instead of saving it to the database, and it only processes the mass_action if the stock status has changed.

[LeeSaferite]

@bob2021 Why did you close the PR?

[bob2021]

Sorry, I should have added a comment - I've made some mistakes in my understanding of how mass_action events are processed. I think this PR is probably ok but I wanted to double check it before anyone else spent time looking at it - I'll reopen if it looks ok.

[seansan]

+1 for the idea (not tested) any update on this one?

[bob2021]

I am no longer involved with Magento development and I will not be contributing any further changes to this PR so I am closing it.

[addison74]

I understand the situation but a simple statement that you are no longer involved in the project was enough without closing the PR, leaving it to the appreciation of others who are still active if your work so far can be useful OpenMage.

[fballiano]

I've solved the conflicts (hopefully correctly since this code is extremely old) and rebased to main. I think this PR is worth checking and testing, please some admins take a look at this.

[fballiano]

So, I took a better look at this and:

• it could be needed to reindex a product also if the is_outofstock didn't change, because there could be low stock triggers or something like that
• removing the "save to db" is interesting but everything has to be processed in the same run, or it won't be resumable
• the way it's coded now kinda resemble a queue like approach, it's not the best since OM doesn't really have queues but I (today) feel it's better to have it this way in case we can snap-in a queue in the future

So, for the time being, I prefer to close it