Automatically sets language_group_id for master collections.

This change handles the multilingual collection structure by setting the language_group_id to the record's own ID for master collections (collections without a language_group_id). This creates a self-referential relationship where master collections point to themselves, while translations point to their master collection's ID.

Behavior

• Master collections: When language_group_id is nil during creation, the change automatically sets it to the record's own ID after insertion using an after_action hook.

• Translation collections: When language_group_id is explicitly provided (pointing to a master collection), the changeset passes through unchanged.

Implementation Details

The change uses after_action to perform the update because we need the record's ID first (generated during insertion). The update:

• Uses the record's site_id as the tenant context
• Bypasses authorization (internal system operation)
• Updates only the language_group_id field

Usage

create :create do
  change MishkaCmsCore.Runtime.Resources.Changes.SetLanguageGroupId
end

In the same write

Pass before_action?: true and the group is written WITH the row instead of by a second write after it:

create :create do
  change {MishkaCmsCore.Runtime.Resources.Changes.SetLanguageGroupId, before_action?: true}
end

update :update do
  change {MishkaCmsCore.Runtime.Resources.Changes.SetLanguageGroupId, before_action?: true}
end

The id is already on a create's changeset by the time a before-action runs, so nothing waits for the insert. MishkaCmsCore.Runtime.Page needs this: its :update validates and signs code, versions the page, broadcasts it and queues a compile, so the second write turned one save into two versions, two broadcasts and two compile jobs.

On an update the same rule keeps a group from being emptied — a record whose group is set to nil becomes the master of a group of its own rather than a record with no group at all.

On a restore it gives a group to a record archived before it had one. A prevent_archived_*_updates trigger refuses every other write to an archived row, so the restoring write is the first one that can:

update :unarchive do
  change set_attribute(:archived_at, nil)
  change {MishkaCmsCore.Runtime.Resources.Changes.SetLanguageGroupId, before_action?: true}
end

Example Flow

Creating a master collection (English):

# User provides: language_group_id = nil
Ash.create(Collection, %{name: "Tech", language: "en", ...}, tenant: site_id)
# After insert: language_group_id automatically set to record.id
# Result: id = "abc123", language_group_id = "abc123"

Creating a translation (Persian):

# User provides: language_group_id = "abc123" (master's ID)
Ash.create(Collection, %{name: "فناوری", language: "fa", language_group_id: "abc123", ...})
# After insert: language_group_id remains "abc123"
# Result: id = "def456", language_group_id = "abc123"

Database Implications

This creates a structure where:

• Master collections: id == language_group_id
• Translations: language_group_id == master_collection.id
• Query all variants: WHERE language_group_id = X (includes master and all translations)