LiteSpeed ignores requests pipelined after requests with chunked message bodies

When LiteSpeed receives a pipeline in which the first request is chunked, the rest of the requests in the pipeline are ignored, but the connection is not closed, and further requests will be processed in a short period of time.

This can be demonstrated by running the following command on a server running LiteSpeed on port 80:

(
    printf 'POST /a HTTP/1.1\r\nHost: whatever\r\nTransfer-Encoding: chunked\r\n\r\n0\r\n\r\nGET /b HTTP/1.1\r\nHost: whatever\r\n\r\n'
    sleep 1
    printf 'DELETE /c HTTP/1.1\r\nHost: whatever\r\n\r\n'
) | nc localhost 80

You should see the server respond to the POST and the DELETE request, but not the GET (presumably due to the sleep).

I have tested this on LiteSpeed 1.8.1 by using a simple application that echos received request methods. You can reproduce my setup exactly using the Dockerfile here.

This is the output of the above command inside of the resulting Docker container:

HTTP/1.1 200 OK
content-type: text/html; charset=UTF-8
content-length: 141
date: Tue, 09 Jul 2024 20:23:49 GMT
server: LiteSpeed
connection: Keep-Alive

{"headers":[["SG9zdA==","d2hhdGV2ZXI="],["Q29udGVudC1MZW5ndGg=","MA=="]],"body":"","method":"UE9TVA==","uri":"L2E=","version":"SFRUUC8xLjE="}HTTP/1.1 200 OK
content-type: text/html; charset=UTF-8
content-length: 109
date: Tue, 09 Jul 2024 20:23:50 GMT
server: LiteSpeed
connection: Keep-Alive

{"headers":[["SG9zdA==","d2hhdGV2ZXI="]],"body":"","method":"REVMRVRF","uri":"L2M=","version":"SFRUUC8xLjE="}

Base64-decoding the method fields in the above JSON objects shows that only the POST and DELETE were responded to.

Reproduce the behavior with the provided nc pipeline and the linked Dockerfile for the LiteSpeed setup. Trace HTTP/1.1 pipelining around the chunked POST and verify that the server processes the queued GET before the later DELETE. Done means all three requests receive responses without the current delay-dependent omission.