Release v0.57.0

CHANGELOG.md

@@ -8,6 +8,8 @@ This project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.htm
 ## [Development]
 <!-- Do Not Erase This Section - Used for tracking unreleased changes -->
 
+## [0.57.0 - 2026-06-28]
+
 ### Changed
 - **GFQL Cypher parse memoization (perf)**: `parse_cypher` now memoizes its result (LRU over the deterministic lark parse+transform → immutable frozen AST). Repeated identical Cypher queries skip the ~15 ms parse — the dominant per-call cost of small queries (~50% of a Cypher call at 100k rows) — making end-to-end query latency ~1.3–1.7× faster at small/interactive sizes across pandas/polars/cuDF. Safe to share the cached AST: every Cypher AST node is `@dataclass(frozen=True)` and `compile_cypher_query` does not mutate the parsed tree; validation errors still raise and are not cached.
 - **GFQL structured whole-entity returns (#1650)**: Terminal Cypher `RETURN a` (whole node/edge) now emits **structured flattened columns** (`a.id`, `a.val`, `a.kind`, ...) instead of a single Cypher display string (`({id: 51, val: 51, kind: 'a'})`). The per-field columns already exist before projection, so this is "stop collapsing" rather than "rebuild": measured ~2–6.4× faster on pandas and ~2.7–4.3× on cuDF for whole-entity returns (the win grows with row count, since the old text render is O(rows) and the flat form is ~free), and the result is directly usable without re-parsing a string and survives JSON/CSV/Parquet/Arrow serialization and `plot()`. The human-readable Cypher display string remains available on demand via the `render_entity_text(result, alias)` presentation helper. OPTIONAL-MATCH / `WITH`-reentry / grouping paths that synthesize null/absent entities or still consume a single-column entity value are unchanged. Behavior change: callers that previously read the rendered display string from a terminal `RETURN a` column now receive flattened `a.*` columns. Edge case: a whole entity with NO fields to flatten — an entity with no id binding, no properties, and no type/label (in practice only an edge whose graph has no edge-id binding) — has no `{alias}.{field}` columns to emit, so it falls back to the single Cypher-display-text column under the bare alias (value is correct, e.g. `[]`); nodes always carry their id field and always flatten.