fix: stable WebSocket object identity across open/message/close hooks

[MarcelOlsen]

Summary

Fixes WebSocket (ElysiaWS) object identity not being stable across open, message, drain, and close lifecycle hooks.

Previously, every handler created a new ElysiaWS(ws, context) wrapping the same raw
Bun ServerWebSocket, meaning ws in open !== ws in message !== ws in close. This broke identity-based patterns like storing sockets in a Set/Map or attaching per-socket state via properties.

Changes

• src/adapter/bun/index.ts: Cache the ElysiaWS wrapper on ws.data._elysiaWS in the open handler and reuse it in message, drain, and close. Each handler falls back to creating a new instance (??=) as a defensive measure.
• test/ws/connection.test.ts: Added test asserting strict reference equality (===) of the ws object across open, message, and close.

Test plan

• New test: should maintain ws object identity across open/message/close
• All 33 existing WebSocket tests pass (bun test test/ws/)

This resolves #1716

Summary by CodeRabbit

• Chores
  • Optimized WebSocket handling for improved connection stability, resource usage, and consistent per-connection state.
• Tests
  • Added tests verifying socket identity across events, tracking of active sockets, and per-socket state propagation and cleanup.

[coderabbitai]

Walkthrough

The Bun adapter's WebSocket handling now creates and stores a single ElysiaWS wrapper per native socket on ws.data._elysiaWS, reusing it across open, message, drain, and close events; tests were added to verify socket identity and per-socket state persistence across lifecycle events.

Changes

Cohort / File(s)	Summary
WebSocket Adapter Implementation src/adapter/bun/index.ts	Create and reuse a single ElysiaWS wrapper stored on ws.data._elysiaWS; pass that instance to all WS event handlers; set elysiaWS.body on incoming messages; lazy initialization to avoid recreating wrappers per event.
WebSocket Connection Tests test/ws/connection.test.ts	Add tests asserting the same ws object is passed to open/message/close handlers, that sockets can be tracked in a Set across open/close, and that per-socket state in a Map persists across handlers and cleans up on close.

Sequence Diagram(s)

sequenceDiagram
  participant Client
  participant BunAdapter as Bun WS
  participant ElysiaWS as Wrapper

  Client->>BunAdapter: connect (open)
  BunAdapter->>ElysiaWS: create if missing -> store on ws.data._elysiaWS
  BunAdapter->>ElysiaWS: call open(handler) with same wrapper

  Client->>BunAdapter: send message
  BunAdapter->>ElysiaWS: set body, call message(handler) with same wrapper

  Client->>BunAdapter: close
  BunAdapter->>ElysiaWS: call close(handler) with same wrapper
  BunAdapter-->>ElysiaWS: optional cleanup (remove from ws.data)

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Estimated code review effort

🎯 2 (Simple) | ⏱️ ~10 minutes

Possibly related issues

• Websockets object identity is not stable across open/message/close hooks #1716: Implements reuse of a single ElysiaWS wrapper stored on ws.data._elysiaWS, addressing socket identity instability across hooks.

Poem

🐰
A single wrap for every hop and close,
One faithful friend wherever data flows.
Open, message, close — the same small stew,
I nibble bugs and hop; the socket's true. 🥕✨

🚥 Pre-merge checks | ✅ 4

✅ Passed checks (4 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly and specifically describes the main fix: ensuring stable WebSocket object identity across lifecycle hooks, which is the central change in this PR.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Merge Conflict Detection	✅ Passed	✅ No merge conflicts detected when merging into main
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.

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✨ Finishing touches

• 📝 Generate docstrings

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Post copyable unit tests in a comment

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[MarcelOlsen]

@coderabbitai review

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Actionable comments posted: 1

🤖 Fix all issues with AI agents

In `@src/adapter/bun/index.ts`:
- Around line 560-566: The TS2345 arises because storing new ElysiaWS(ws,
context as any) in elysiaWS loses the inline any-cast used previously when
calling options.open; to fix, keep the local elysiaWS but cast it back to any
when invoking options.open (e.g., pass options.open?.(elysiaWS as any)), or
alternatively cast at declaration (const elysiaWS = new ElysiaWS(ws, context as
any) as any); update the call site in the handleResponse invocation so
options.open receives the same any-typed value; relevant symbols: ElysiaWS,
elysiaWS, ws, options.open, handleResponse.

🧹 Nitpick comments (1)

src/adapter/bun/index.ts (1)

560-561: The _elysiaWS property on ws.data is untyped.

ws.data._elysiaWS is set dynamically without any type declaration. This works because ws is typed as ServerWebSocket<any>, but it would be cleaner to add _elysiaWS to the data shape if a type exists for it. Not blocking, but worth noting for future maintainability.

[pkg-pr-new]

Open in StackBlitz

npm i https://pkg.pr.new/elysiajs/elysia@1737

commit: c9d6c09

[MarcelOlsen]

@coderabbitai review

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