Fix: swallow _receiveTask exceptions in SseClientSessionTransport.Clo…#1432
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xue-cai wants to merge 1 commit intomodelcontextprotocol:mainfrom
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Fix: swallow _receiveTask exceptions in SseClientSessionTransport.Clo…#1432xue-cai wants to merge 1 commit intomodelcontextprotocol:mainfrom
xue-cai wants to merge 1 commit intomodelcontextprotocol:mainfrom
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…seAsync
When SseClientSessionTransport.ConnectAsync fails (e.g. the SSE GET
returns 405), its catch block calls CloseAsync() before wrapping the
error in InvalidOperationException("Failed to connect transport", ex).
However, CloseAsync() awaits _receiveTask which is already faulted
with the same HttpRequestException. Since there is no try-catch around
that await, the exception propagates out of CloseAsync, out of the
catch block, and the InvalidOperationException wrapping is never
reached.
This means callers of ConnectAsync receive an unwrapped
HttpRequestException instead of the documented InvalidOperationException
wrapper, which breaks exception filtering in downstream code.
The fix wraps `await _receiveTask` in CloseAsync with a try-catch that
swallows both OperationCanceledException (normal shutdown) and other
exceptions (already observed and forwarded via
_connectionEstablished.TrySetException in ReceiveMessagesAsync).
Includes a regression test that verifies ConnectAsync throws
InvalidOperationException (not HttpRequestException) when both
Streamable HTTP POST and SSE GET fallback fail.
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
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…seAsync
When SseClientSessionTransport.ConnectAsync fails (e.g. the SSE GET returns 405), its catch block calls CloseAsync() before wrapping the error in InvalidOperationException("Failed to connect transport", ex).
However, CloseAsync() awaits _receiveTask which is already faulted with the same HttpRequestException. Since there is no try-catch around that await, the exception propagates out of CloseAsync, out of the catch block, and the InvalidOperationException wrapping is never reached.
This means callers of ConnectAsync receive an unwrapped HttpRequestException instead of the documented InvalidOperationException wrapper, which breaks exception filtering in downstream code.
The fix wraps
await _receiveTaskin CloseAsync with a try-catch that swallows both OperationCanceledException (normal shutdown) and other exceptions (already observed and forwarded via_connectionEstablished.TrySetException in ReceiveMessagesAsync).
Includes a regression test that verifies ConnectAsync throws InvalidOperationException (not HttpRequestException) when both Streamable HTTP POST and SSE GET fallback fail.
Motivation and Context
How Has This Been Tested?
Breaking Changes
Types of changes
Checklist
Additional context