Fix incorrect resend of session-level messages with ForceResendWhenCorruptedStore

[Copilot]

Fix: Prevent incorrect resend of session-level messages when ForceResendWhenCorruptedStore is enabled

Progress:

• Understand the problem and current implementation
• Modify resendMessages() in Session.java to:
  • Remove dependency on forceResendWhenCorruptedStore flag for admin message detection
  • Add special handling for Reject messages (MsgType=3) - should be resent
  • Properly skip other session-level messages with gap fill
  • Ensure application messages are resent normally
  • Keep original Heartbeat handling for corrupted store (per review feedback)
  • Use session-specific logging instead of global LOG (per review feedback)
• Create unit test in SessionTest.java to verify fix
• Add setter in SessionFactoryTestSupport.Builder for forceResendWhenCorruptedStore
• Run SessionTest suite - all 72 tests pass
• Address review feedback

Summary

✅ Core fix for admin message handling maintained
✅ Original Heartbeat logic for corrupted store restored
✅ Session-specific logging used throughout
✅ All session tests pass (72/72)

Original prompt

Problem Description

When the option ForceResendWhenCorruptedStore is enabled and a ResendRequest is received, session-level messages (admin messages) are incorrectly being resent. This violates the FIX specification, which states that Reject messages are the only session-level messages that must be resent. Other session-level messages like Logon, Logout, and Heartbeat should be skipped using SequenceReset GapFill messages.

Reference issue: #597

Root Cause

The bug is located in the resendMessages() method in quickfixj-core/src/main/java/quickfix/Session.java around lines 2367-2386.

The problematic code is:

if (MessageUtils.isAdminMessage(msgType) && !forceResendWhenCorruptedStore) {
    if (begin == 0) {
        begin = msgSeqNum;
    }
} else {
    initializeResendFields(msg);
    if (resendApproved(msg)) {
        // ... resends the message
    }
}

When forceResendWhenCorruptedStore is true, the condition MessageUtils.isAdminMessage(msgType) && !forceResendWhenCorruptedStore evaluates to false, causing ALL messages (including session-level ones) to fall into the else branch where they are resent. This also incorrectly calls toApp() on session-level messages.

Expected Behavior

According to the FIX specification:

1. Only Reject messages among session-level messages should be resent
2. All other session-level messages (Logon, Logout, Heartbeat, TestRequest, etc.) should NOT be resent
3. Instead, SequenceReset GapFill messages should be sent to skip over these sequence numbers
4. Application messages should continue to be resent normally

Solution

Modify the resendMessages() method to:

1. Remove the dependency on forceResendWhenCorruptedStore flag when determining whether to resend admin messages
2. Add special handling for Reject messages: Among session-level messages, only Reject (MsgType=3) should be resent
3. Properly skip other session-level messages with SequenceReset GapFill
4. Improve corrupted store handling: When the store is corrupted, use placeholders instead of fake Heartbeat messages, then properly gap fill over missing messages

Changes Required

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

In the resendMessages() method (around lines 2320-2411), update the logic to:

1. Handle corrupted store by adding null placeholders instead of creating fake Heartbeat messages
2. Check if messages are admin messages and handle appropriately:
   • If it's a Reject message: resend it (call initializeResendFields, resendApproved, and send)
   • If it's any other session-level message: mark for gap fill (set begin if needed)
   • If it's an application message: resend it normally
3. Ensure proper SequenceReset GapFill generation for skipped messages

Test Case

Create a unit test in quickfixj-core/src/test/java/quickfix/SessionTest.java that:

1. Enables ForceResendWhenCorruptedStore option
2. Stores some session-level messages (Logon, Heartbeat) and application messages in the message store
3. Triggers a ResendRequest
4. Verifies that:
   • Application messages are resent with PossDupFlag
   • Session-level messages (except Reject) are NOT resent
   • SequenceReset GapFill messages are sent to skip session-level message sequence numbers
   • toApp() is not called on session-level messages

Benefits

• Compliant with FIX specification
• Session-level messages (except Reject) will no longer be incorrectly resent
• toApp() will not be called on session-level messages during resend
• Proper SequenceReset GapFill messages will be generated
• Better handling of corrupted message stores

This pull request was created from Copilot chat.

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[chrjohn]

@copilot please roll back these changes and restore the former logic that puts Heartbeats into the messages list.
Moreover, use the session-specific log instead of the global LOG.

[Copilot]

Done in e180fa4. Restored the original logic that creates Heartbeat messages and changed to use getLog().onErrorEvent() for session-specific logging.

[chrjohn]

@copilot this can be removed also.

[Copilot]

Done in e180fa4. Removed the null placeholder handling code.