This moves a step closer to having a simple and straightforward way to
configure the app's mail delivery which doesn't require to be a nuclear
engineer to troubleshoot mail issues.
It happens way too often that servers have mail config broken when
restarted or redeployed and it takes too much brain power to fix it. No
doubt; it's way too complex.
I chose to leave this page's form fields but "Send mails as" as
read-only. This other field is still used by instance manager to
troubleshoot mail issues.
This removes an N+1 with taggings but doesn't solve the one with tags.
Using `includes(taggings: :base_tags)` based on
47da5036de/lib/acts_as_taggable_on/taggable.rb (L83-L84)
wasn't enough to solve it and I got to stop here. This is scope-creeping
too much.
We get from an initial INNER JOIN with variants and products to fetch
the variant overrides + N queries like:
```sql
SELECT "spree_variants".* FROM "spree_variants" WHERE
"spree_variants"."deleted_at" IS NULL AND "spree_variants"."id" = $1
LIMIT 1 [["id", 1545]]
SELECT "spree_products".* FROM "spree_products" WHERE
"spree_products"."id" = $1 LIMIT 1 [["id", 604]]
```
to the same initial INNER JOIN + just 2 queries like:
```sql
SELECT "spree_variants".* FROM "spree_variants" WHERE
"spree_variants"."deleted_at" IS NULL AND "spree_variants"."id" IN
(1551, 1554)
SELECT "spree_products".* FROM "spree_products" WHERE
"spree_products"."deleted_at" IS NULL AND "spree_products"."id" IN (606,
607)
```
In the line below we filter them out in Ruby so it's a waste of
resources. The fundamental difference is that `#includes` and
`#references` results in LEFT JOINs, whereas `#joins` results in INNER
JOIN, and because there's a default scope on `deleted_at IS NULL`, these
are not included in the result set.
This however, requires us to move away from the current algorithm but
unfortunately we can't refactor it completely yet.
Before:
```sql
SELECT *
FROM "variant_overrides"
LEFT OUTER
JOIN "spree_variants"
ON "spree_variants"."id" = "variant_overrides"."variant_id"
AND "spree_variants"."deleted_at" IS NULL
LEFT OUTER
JOIN "spree_products"
ON "spree_products"."id" = "spree_variants"."product_id"
AND "spree_products"."deleted_at" IS NULL
WHERE "variant_overrides"."permission_revoked_at" IS NULL
AND "variant_overrides"."hub_id" IN (
SELECT "enterprises"."id"
FROM "enterprises"
INNER
JOIN "enterprise_roles"
ON "enterprise_roles"."enterprise_id" = "enterprises"."id"
WHERE (enterprise_roles.user_id = ?)
AND (sells != 'none')
ORDER BY name)
```
After:
```sql
SELECT "variant_overrides".*
FROM "variant_overrides"
INNER
JOIN "spree_variants"
ON "spree_variants"."id" = "variant_overrides"."variant_id"
AND "spree_variants"."deleted_at" IS NULL
INNER
JOIN "spree_products"
ON "spree_products"."id" = "spree_variants"."product_id"
AND "spree_products"."deleted_at" IS NULL
WHERE "variant_overrides"."permission_revoked_at" IS NULL
AND "variant_overrides"."hub_id" IN (
SELECT "enterprises"."id"
FROM "enterprises"
INNER
JOIN "enterprise_roles"
ON "enterprise_roles"."enterprise_id" = "enterprises"."id"
WHERE (enterprise_roles.user_id = ?)
AND (sells != 'none')
ORDER BY name)
```
This is covered in the test suite by
spec/controllers/admin/variant_overrides_controller_spec.rb:72. It keeps
passing so we're good to go.
#update_column(s) skips callbacks (which is useful), but it doesn't change the updated_at field on the record by default (which we should be doing in these cases).
This change is made in Spree 2.2 here: b367c629ce
Whatever fee adjustments there are on other line items should be left alone (not recreated), and whatever fee adjustments are already on the order should just be updated.
This method is named "update distribution charge". What this method actually does is delete all of the fee adjustments on an order and all it's line items, then recreate them all from scratch. We call this from lots of different places all the time, and it's incredibly expensive. It even gets called from inside of transactions being run inside callbacks. Renaming it hopefully will add a bit of clarity.
This needs to be a lot more granular!
