Improve Engine.IO v4 polling compatibility and modernize internal typing and transport handling

CHANGELOG.md

@@ -1,42 +1,68 @@
-## 1.0.1
-
-**Bug Fix:**
-
-* [#45](https://github.com/rikulo/socket.io-dart/issues/45) [BUG] Calling close on Server raises ConcurrentModificationError
-
-**New Feature:**
-
-* [#47](https://github.com/rikulo/socket.io-dart/pull/47) Added Future to start and stop server
-
-## 1.0.0
-
-**New Feature:**
-
-* [#33](https://github.com/rikulo/socket.io-dart/issues/33) Null safety
-
-
-## 0.9.4
-
-**Bug Fix:**
-
-* [#23](https://github.com/rikulo/socket.io-dart/issues/23) [BUG] Calling close on Server raises ConcurrentModificationError
-
-## 0.9.3
-
-**Bug Fix:**
-
-* [#18](https://github.com/rikulo/socket.io-dart/pull/18) make sure it is accessing the rooms map
-
-
-## 0.9.2
-
-**Bug Fix:**
-
-* [#17](https://github.com/rikulo/socket.io-dart/pull/17) inference error
-
-
-## 0.9.1+1
-
-**New Feature:**
-
-* [#16](https://github.com/rikulo/socket.io-dart/pull/16) Apply Pedantic recommendations
+# Changelog
+
+All notable changes to this fork are documented here.
+This fork tracks upstream [`rikulo/socket.io-dart`](https://github.com/rikulo/socket.io-dart)
+and adds the fixes listed below.  Once these are accepted upstream the
+`dependency_override` in consuming projects can be removed.
+
+---
+
+## 2.0.1 – 2026-05-03
+
+### Fixed
+
+- **Polling transport – packet splitting** (`lib/src/engine/transport/polling_transport.dart`)  
+  `onData()` previously called `PacketParser.decodePayload()` which cannot
+  parse Engine.IO v4 / Socket.IO v3+ payloads.  Replaced with a custom
+  `_splitPackets()` splitter that locates packet boundaries on `]`, `}` or
+  `"` followed by a digit, then decodes each packet individually via
+  `PacketParser.decodePacket()`.  This makes polling fully equivalent to the
+  WebSocket transport for all current Socket.IO clients (JS, browser, Dart).
+- **Polling transport – connection close race** (`doWrite / respond`)  
+  `respond()` was synchronous and used `unawaited(connect!.close())`, causing
+  premature or failed connection closes that produced *xhr poll error* on
+  clients.  `respond` is now `async` and `await`s `connect!.close()`.
+- **Polling transport – CORS headers**  
+  Added `Access-Control-Allow-Origin`, `Access-Control-Allow-Credentials`,
+  `Access-Control-Allow-Methods`, and cache-control headers to every polling
+  response so browser and cross-origin Dart clients do not get blocked.
+- **Namespace – typed connection handler**  
+  `onConnection()` now casts the raw `dynamic` listener argument to `Socket`
+  before invoking the typed `EventHandler<Socket>` callback.
+
+### Added
+
+- `example/polling_smoke.dart` – raw Engine.IO v4 polling smoke test that
+  can be run against a live server to verify the polling fix end-to-end.
+- `--with-polling-smoke` flag in `tool/check.sh`.
+
+---
+
+## 2.0.0 – 2025-10-11
+
+### Changed (breaking – Dart 3 migration)
+
+- Minimum SDK raised to `>=3.0.0 <4.0.0`.
+- Dart 3 modernisation: sealed classes, records, exhaustive switches, and
+  improved null-safety throughout.
+- Package renamed from `tp_socket_io` to `socket_io`; all import paths
+  updated (`package:socket_io/socket_io.dart`).
+
+### Added
+
+- **Typed API** – value objects (`ConnectionId`, `RoomName`, `EventName`,
+  `NamespaceName`, `PortNumber`, …) and sealed domain models
+  (`SocketIOPacket`, `SocketIOError`, `TransportData`, …) alongside the
+  legacy untyped API for gradual migration.
+- **Expanded test suite** – 773 tests across 34 files covering every value
+  object, model, extension, and error type.
+- `doc/ARCHITECTURE.md`, `doc/TYPE_SAFE_EXAMPLES.md`,
+  `doc/TYPE_SAFETY_MIGRATION_GUIDE.md`, `doc/QUICK_REFERENCE.md`.
+
+---
+
+## 1.0.1 – upstream baseline
+
+Upstream release from [`rikulo/socket.io-dart`](https://github.com/rikulo/socket.io-dart).
+See [upstream CHANGELOG](https://github.com/rikulo/socket.io-dart/blob/master/CHANGELOG.md)
+for history prior to this fork.