cultcache-rs: lookups cross-type test, changelog and README entries

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

packages/cultcache-rs/CHANGELOG.md

@@ -13,6 +13,7 @@ only in git history.
 
 ### Added
 
+- Lookups, matching the C# `GetByName`, `GetByIndex` and `GetGlobal`. `#[cultcache(name)]` and `#[cultcache(index)]` / `#[cultcache(index = "alias")]` on `DatabaseEntry` fields and `#[cultcache(global)]` on the struct give `CultCache::get_by_name`, `get_by_index` and `get_global`. An empty name and a blank index value are not found; records of one type sharing a name or value find the one with the smallest key. A second record of a global type under another key is refused on every write path and on load with `CultCacheSecondGlobal`. Two `name` members, or two members with one index alias, are refused at compile time. A member's text comes from `CultLookupValue` (`String`, `Option` of one, integers, `bool`, `char`).
 - `SchemaConflictError`, the typed refusal of a write the catalog cannot describe: records of different types under one schema id, or an arrived schema and a registered one that share an id and disagree on the schema name. A whole-store write (`push_all`) refuses with it, names the schema id, the names involved and a record key, writes nothing and leaves the file as it is. A caller tells it apart with `error.downcast_ref::<SchemaConflictError>()`.
 
 ## [0.3.1]

packages/cultcache-rs/README.md

@@ -174,6 +174,9 @@ without pretending Rust has runtime reflection hiding under the floorboards.
 - `get_required_envelope::<T>`
 - `get_all::<T>`
 - `get_all_with_keys::<T>`
+- `get_by_name::<T>`
+- `get_by_index::<T>`
+- `get_global::<T>`
 - `soa::<T>`
 - `put::<T>`
 - `put_envelope::<T>`

packages/cultcache-rs/tests/lookups.rs

@@ -32,6 +32,20 @@ struct Gadget {
     category: String,
 }
 
+/// Sorts after `Item` and has its exact shape: a lookup that ran past the end of its own type would answer from it.
+#[derive(Clone, Debug, PartialEq, Eq, DatabaseEntry)]
+#[cultcache(type = "zed")]
+struct Zed {
+    #[cultcache(key = 0, name)]
+    name: String,
+    #[cultcache(key = 1, index)]
+    category: String,
+    #[cultcache(key = 2, index = "sku")]
+    code: Option<String>,
+    #[cultcache(key = 3, default)]
+    value: u32,
+}
+
 #[derive(Clone, Debug, PartialEq, Eq, DatabaseEntry)]
 #[cultcache(type = "settings", global)]
 struct Settings {
@@ -63,6 +77,7 @@ fn cache() -> CultCache {
     let mut cache = CultCache::new();
     cache.register_entry_type::<Item>().unwrap();
     cache.register_entry_type::<Gadget>().unwrap();
+    cache.register_entry_type::<Zed>().unwrap();
     cache.register_entry_type::<Settings>().unwrap();
     cache.register_entry_type::<Plain>().unwrap();
     cache.register_entry_type::<Numbered>().unwrap();
@@ -142,10 +157,12 @@ fn lookups_never_cross_types() {
     let mut cache = cache();
     cache.put("item:a", &item("same", "same", None)).unwrap();
     cache.put("gadget:a", &Gadget { name: "same".into(), category: "same".into() }).unwrap();
+    cache.put("zed:a", &Zed { name: "same".into(), category: "same".into(), code: None, value: 0 }).unwrap();
 
     assert_eq!(cache.get_by_name::<Gadget>("same").unwrap().unwrap().name, "same");
     cache.delete::<Item>("item:a").unwrap();
     assert_eq!(cache.get_by_name::<Item>("same").unwrap(), None);
+    assert_eq!(cache.get_by_index::<Item>("category", "same").unwrap(), None);
     assert!(cache.get_by_name::<Gadget>("same").unwrap().is_some());
     assert!(cache.get_by_index::<Gadget>("category", "same").unwrap().is_some());
 }