AshUi.Notification.DerivedReads (ash_ui v0.1.0)

Subscription edges for what a rendered record DERIVES: "whatever a page reads, it subscribes to".

The relationship walk in each transport adapter subscribes a page to the relationships actually loaded on its record. A calculation or aggregate the view renders reads more than that: Ash loads its dependencies as hidden internal loads, so those rows never appear on the record and the walk never sees them. This module turns the declaration-derived read set (AshUi.Reload.derived_reads/2, the same derivation the reload contract narrows with) into subscription edges for one loaded record:

the first hop of a relationship read, taken from the loaded record, is key-matched on destination_attribute = record[source_attribute] and carries the relationship filter with the record as parent — the same precision the relationship walk registers;
later hops, and aggregates over unrelated resources, have no derivable key and subscribe at resource level (attrs: []);
a first hop the record already has loaded, with nothing beyond it, is left to the walk at the root, whose reload of that relationship already recomputes every dependent root (Reload.dependent_roots_for_paths/2).

Each edge reloads prefix ++ [field]: the derived value itself, recomputed by Ash with its hidden dependencies, instead of materializing the relationship on the record.

Summary

Types

edge()

Functions

edges(record, load_spec, prefix)

The derived-read subscription edges of record, whose view load at this level is load_spec, reached through relationship path prefix.

Types

edge()

@type edge() :: %{
  key: term(),
  resource: module(),
  attrs: keyword(),
  filter: term(),
  parent: struct() | nil,
  reload_scope: [atom()]
}

Functions

edges(record, load_spec, prefix)

@spec edges(struct(), term(), [atom()]) :: [edge()]

The derived-read subscription edges of record, whose view load at this level is load_spec, reached through relationship path prefix.