fix: prevent unbounded onclose handler chain on transport reconnect (#2607) - #2821
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…odelcontextprotocol#2607) Protocol.connect() wrapped transport.onclose in a new closure on every call. When connect() is invoked multiple times on the same transport (e.g. session-resuming reconnects), each call nests a new closure around the previous one. Every transport close then walks the entire accumulated chain — a memory leak proportional to the number of reconnects. The fix detects when the transport is the same as the previously connected one and skips re-wrapping onclose/onerror/onmessage, so the existing wrapper (which already chains the prior handlers and calls this._onclose()) is reused instead of nested again.
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Protocol.connect() wrapped transport.onclose in a new closure on every call. When connect() is invoked multiple times on the same transport (e.g. session-resuming reconnects in StreamableHTTP), each call nests a new closure around the previous one, creating an unbounded chain. Every transport close then walks the entire accumulated chain — a memory leak proportional to the number of reconnects.
The fix detects when the transport is the same as the previously connected one and skips re-wrapping onclose/onerror/onmessage, so the existing wrapper (which already chains the prior handlers and calls this._onclose()) is reused instead of nested again.
Fixes #2607