M2P-161 Stop pushing model/quote JS script

[vitaliyreznikov]

We introduced an issue in #796. Actually it was known magento issue that was fixed in new Magento versions, see magento/magento2#23099 , magento/magento2#14412, magento/magento2#21432

Under some conditions, Magento JS script produced an error because they initialated wrong.

We had a fix #808 but now I see it doesn't affect the root of the issue.

In PR 796 we added require(['Magento_Checkout/js/model/quote'] ...) thing. This requireJS API means we push model/quote script to load if it wasn't loaded before. Under some very rare conditions, it triggers incorrect initializing.

So solution the same as in magento/magento2#21432 : don't load module/quote script before DOM.loaded. We know that when DOM.loaded we have all parameters to initialize this script.

The issue about a race condition, so it's quite hard to reproduce it. Looks like it happens very rarely.
We need some (or all) of the following conditions:

• site works slowly
• browser work slowly (IE11 for example)
• the first page load, so we don't have scripts in browser cache.
• site works in developer mode

Fixes: [M2P-161]

#changelog M2P-161 Stop pushing model/quote JS script

Type of change

• Bug fix (change which fixes an issue)
• New feature (change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

How Has This Been Tested?

Please validate that you have tested your change in at least one of the following areas:

• Successfully tested locally (or docker image)
• Successfully tested on a staging or sandbox server
• Successfully tested on a merchant's staging server

For PR Reviewer

• Reviewed unit tests to make sure we are using real components rather than mocks as much as possible?
• For any major change (observer, new Bolt feature, core Magento interaction) we must add a feature switch, did you verify this?

Checklist:

• My code follows the style guidelines of this project.
• I have performed a self-review of my own code.
• I have commented my code, particularly in hard-to-understand areas.
• New and existing unit tests pass locally with my changes.
• I have created or modified unit tests to sufficiently cover my changes.
• I have added my Jira ticket link and provided a changelog message.

[codecov]

Codecov Report

Merging #822 into master will increase coverage by 0.17%.
The diff coverage is n/a.

@@             Coverage Diff              @@
##             master     #822      +/-   ##
============================================
+ Coverage     92.86%   93.03%   +0.17%     
- Complexity     1378     1428      +50     
============================================
  Files           104      104              
  Lines          4668     4811     +143     
============================================
+ Hits           4335     4476     +141     
- Misses          333      335       +2     

[matt-thomason]

What about the other two instances in this replacejs.phtml file where we rely on domReady!?

[vitaliyreznikov]

What about the other two instances in this replacejs.phtml file where we rely on domReady!?

Good point, but other things are work :) and we haven't changed them for months. Looks like only 'Magento_Checkout/js/model/quote' is brittle enough and we use it only in place I fix in this PR.

Maybe it makes sense to run all code after domReady, but I think it's too big change for hotfix PR. Let's discuss this during other JS refactoring tasks..

[matt-thomason]

That is reasonable, thanks for talking it out.