EncodingId as a sealed interface; ArrayNode carries the typed id

CHANGELOG.md

@@ -17,7 +17,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - `Compute.filteredSum` over a dictionary-encoded filter column is ~20× faster (best runs ~30×): the predicate is resolved against the dictionary's value pool once and the raw `u8` codes are scanned directly from their backing segments, instead of decoding every row through the per-element accessor — a fused `SUM(measure) WHERE category = …` over 100M rows drops from ~760 ms to ~38 ms. ([85e251cc](https://github.com/dfa1/vortex-java/commit/85e251cc))
 - `Compute.filteredAggregate` takes the same dictionary code-scan lane (`COUNT(*)` included) — ~22× faster on the same workload (~980 ms → ~46 ms over 100M rows), which the Calcite `WHERE`-filtered aggregate push-down inherits on its boundary chunks. ([145791c7](https://github.com/dfa1/vortex-java/commit/145791c7), [6e6d7dd0](https://github.com/dfa1/vortex-java/commit/6e6d7dd0))
 - A multi-column `AND` filter no longer forfeits the dictionary lane: the dict-encoded leaf drives the code scan and the remaining predicates are evaluated only on its matches — `SUM(…) WHERE category = 7 AND price > 500` over 100M rows drops from ~2.3 s to ~200 ms (~11×). ([12e13501](https://github.com/dfa1/vortex-java/commit/12e13501))
-- `reader.decode.ArrayNode` is now a single record carrying the raw encoding-id string from the wire; the `KnownArrayNode` / `UnknownArrayNode` split is gone. Custom `EncodingDecoder` implementations keep working unchanged — decode dispatch is keyed by the id string, and the `allowUnknown` passthrough behaves as before. ([3b25a97d](https://github.com/dfa1/vortex-java/commit/3b25a97d))
+- `core.model.EncodingId` is now a sealed interface: the spec constants live in the nested `WellKnown` enum (re-exported, so `EncodingId.VORTEX_FOO` call sites compile unchanged) and `Custom` wraps any other wire string, which for the first time lets third-party `EncodingDecoder`/`EncodingEncoder` implementations declare ids outside the spec set. `parse` is total over non-blank ids — an unknown id yields a typed `Custom` instead of an empty `Optional`. ([ea88a91b](https://github.com/dfa1/vortex-java/commit/ea88a91b))
+- `reader.decode.ArrayNode` is a single record carrying the typed `EncodingId`; the `KnownArrayNode`/`UnknownArrayNode` split and the `ArrayNode.of` factory are gone. Decode dispatch, the `allowUnknown` passthrough, and error messages are unchanged. A crafted file with a blank encoding id now fails as `VortexException` instead of escaping as `IllegalArgumentException`. ([21810d7e](https://github.com/dfa1/vortex-java/commit/21810d7e))
 
 ## [0.11.0] — 2026-06-28
 

CLAUDE.md

@@ -28,12 +28,12 @@ core    — everything lives under `io.github.dfa1.vortex.core.*`:
           core.error    VortexException
           core.compute  FastLanes, PrimitiveArrays
           core.fbs / core.proto — generated wire codecs + their runtimes
-reader  — VortexReader, VortexHttpReader, VortexHandle, ReadRegistry, ExtensionDecoder,
-          Chunk, ArrayStats, ScanOptions, RowFilter; file internals (Footer, Layout, Trailer,
+reader  — VortexReader, VortexHttpReader, VortexHandle, ReadRegistry, Chunk, ArrayStats,
+          ScanOptions, RowFilter; file internals (Footer, Layout, Trailer,
           PostscriptParser, …)
           reader.array  — Array + all subtypes (decode outputs)
           reader.decode — EncodingDecoder, DecodeContext, ArrayNode + *EncodingDecoder impls
-          reader.extension — Date/Time/Timestamp/Uuid ExtensionDecoder
+          reader.extension — ExtensionDecoder + Date/Time/Timestamp/Uuid impls
 writer  — VortexWriter, WriteRegistry, WriteOptions, ExtensionEncoder
           writer.encode — EncodingEncoder, EncodeContext, NullableData + *EncodingEncoder impls,
           extension encoders
@@ -135,9 +135,9 @@ Add `EncodingId` enum constant `VORTEX_FOO("vortex.foo")`, then per side:
 ### Adding an extension type
 
 Add `ExtensionId` constant, then per side:
-- **Decode:** `FooExtensionDecoder implements ExtensionDecoder` in `reader.extension`; register via
-  `ReadRegistry.builder().register(new FooExtensionDecoder())` — **no service file**
-  (`registerServiceLoaded()` does not discover `ExtensionDecoder`).
+- **Decode:** singleton `FooExtensionDecoder implements ExtensionDecoder` in `reader.extension` +
+  a `case VORTEX_FOO` in `Chunk.as()` — not registry-managed, **no service file**
+  (`registerServiceLoaded()` only discovers `EncodingDecoder`).
 - **Encode:** `FooExtensionEncoder implements ExtensionEncoder` in `writer` + FQN in
   `writer/.../META-INF/services/io.github.dfa1.vortex.writer.ExtensionEncoder`