Summary

When receiving data with chunked transfer encoding, if the connection is closed by the peer without sending the terminating 0\r\n\r\n, or if a chunk is not sent completely, HTTPChunkedInputStream now sets a MessageException that can be retrieved via session.networkException().

Problem

Previously, when a server closed the connection gracefully (FIN) before completing the chunked response:

• The stream would return EOF as if the data was delivered correctly
• session.networkException() returned nullptr
• There was no way to detect that the data was incomplete

This only occurred with graceful close (FIN). Connection reset (RST) already raised an exception properly.

Solution

Modified HTTPChunkedStreamBuf::readFromDevice() to detect premature connection closure in two scenarios:

1. Incomplete chunk header: When chunk size parsing fails due to unexpected EOF
2. Incomplete chunk data: When read() returns 0 or less while expecting more data (_chunk > 0)

In both cases, a MessageException("Incomplete chunked transfer encoding") is now set via _session.setException().

Testing

The fix can be tested using the reproduction steps from issue #5032. After the fix, session.networkException() will return the MessageException when the connection is closed before receiving the complete chunked response.

Fixes #5032