Enabling a previously disabled session might lead to message loss

[chrjohn]

Describe the bug
When a session is disabled (i.e. after calling logout()) it will no longer get reset as defined by its SessionSchedule. This is because next() returns early when a session is disabled:

quickfixj/quickfixj-core/src/main/java/quickfix/Session.java

Lines 1952 to 1963 in f8ba074

	public void next() throws IOException {
	if (!isEnabled()) {
	if (isLoggedOn()) {
	if (!state.isLogoutSent()) {
	getLog().onEvent("Initiated logout request");
	generateLogout(state.getLogoutReason());
	}
	} else {
	return;
	}
	}

To Reproduce

Will try to create a unit test in due course.

Manual steps:

• have a session that is disabled and has not been used at the current day (i.e. there was no established session for that day)
• send messages to that Session via sendToTarget() - the messages will end up in the Session's message store.
• establish a connection to the session
• based on QFJ's internal timer, the next() method will be called within a second and a reset will be done, effectively removing the Sessions's message store

Expected behavior

Session should get reset based on its schedule even when it is disabled.

[philipwhiuk]

A simple optimisation we do for this is to not bother resetting unless the sequence numbers have advanced.

[Ra9huvansh]

Hey @chrjohn, can I pick this one up? Based on @philipwhiuk's suggestion, I plan to implement the fix to skip resetting unless sequence numbers have advanced.

[chrjohn]

Hi @Ra9huvansh , please do. Thank you 👍