stems fixes and tests

GEMINI.md

@@ -109,6 +109,8 @@ A `Stem` is **not a JSON Pointer** or a physical path string (like `/properties/
 Because `pg_notify` (Beats) fire rigidly from physical Postgres tables (e.g. `{"type": "phone_number"}`), the Go Framework only ever needs to know: "Does the schema `with_contacts.person` contain the `phone_number` Entity anywhere inside its tree?"
 
 *   **Initialization:** During startup (`jspg_stems()`), the database crawls all Schemas and maps out every physical Entity Type it references. It builds a flat dictionary of `Schema ID -> [Entity Types]` (e.g. `with_contacts.person -> ["person", "contact", "phone_number", "email_address"]`).
+*   **Identifier Prioritization**: When determining if a nested object boundary is an Entity, JSPG natively prioritizes defined `$id` tags over `$ref` inheritance pointers to prevent polymorphic boundaries from devolving into their generic base classes.
+*   **Cyclical Deduplication**: Because Punc relationships often reference back on themselves via deeply nested classes, the Stem Engine applies intelligent path deduplication. If the active `current_path` already ends with the target entity string, it traverses the inheritance properties without appending the entity to the stem path again, eliminating infinite powerset loops.
 *   **Relationship Path Squashing:** When calculating nested string paths structurally to discover these boundaries, JSPG intentionally **omits** properties natively named `target` or `source` if they belong to a native database `relationship` table override. This ensures paths like `phone_numbers/contact/target` correctly register their beat resolution pattern as `phone_numbers/contact/phone_number`.
 *   **The Go Router**: The Golang Punc framework uses this exact mapping to register WebSocket Beat frequencies exclusively on the Entity types discovered.
 *   **The Queryer Execution**: When the Go framework asks JSPG to hydrate a partial `phone_number` stem for the `with_contacts.person` schema, instead of jumping through string paths, the SQL Compiler simply reaches into the Schema's AST using the `phone_number` Type string, pulls out exactly that entity's mapping rules, and returns a fully correlated `SELECT` block! This natively handles nested array properties injected via `oneOf` or array references efficiently bypassing runtime powerset expansion.
@@ -127,7 +129,8 @@ To solve this, JSPG introduces the `DatabaseExecutor` trait inside `src/database
 ### Universal Test Harness (`src/tests/`)
 JSPG abandons the standard `cargo pgrx test` model in favor of native OS testing for a >1000x speed increase (`~0.05s` execution).
 
-1.  **JSON Fixtures**: All core interactions are defined abstractly as JSON arrays in `fixtures/`. Each file contains suites of `TestCase` objects with an `action` flag (`validate`, `merge`, `query`).
+1.  **JSON Fixtures**: All core interactions are defined abstractly as JSON arrays in `fixtures/`. Each file contains suites of `TestCase` objects with an `action` flag (`compile`, `validate`, `merge`, `query`).
 2.  **`build.rs` Generator**: The build script traverses the JSON fixtures, extracts their structural identities, and generates standard `#[test]` blocks into `src/tests/fixtures.rs`.
 3.  **Modular Test Dispatcher**: The `src/tests/types/` module deserializes the abstract JSON test payloads into `Suite`, `Case`, and `Expect` data structures.
-4.  **Unit Context Execution**: When `cargo test` executes, the `Runner` feeds the JSON payloads directly into `case.execute(db)`. Because the tests run natively inside the module via `#cfg(test)`, the Rust compiler globally erases `pgrx` C-linkage, instantiates the `MockExecutor`, and allows for pure structural evaluation of complex database logic completely in memory.
+    *   The `compile` action natively asserts the exact output shape of `jspg_stems`, allowing structural and relationship mapping logic to be tested purely through JSON without writing brute-force manual tests in Rust.
+4.  **Unit Context Execution**: When `cargo test` executes, the runner iterates the JSON payloads. Because the tests run natively inside the module via `#cfg(test)`, the Rust compiler globally erases `pgrx` C-linkage, instantiates the `MockExecutor`, and allows for pure structural evaluation of complex database logic completely in memory in parallel.