NullPointerException in requestBinaryLogStreamMaria when GTID set is empty/null

[KMohnishM]

Summary

BinaryLogClient.requestBinaryLogStreamMaria() throws a NullPointerException when the GTID set is empty or not initialized.

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Description

When the client is initialized with an empty GTID string (setGtidSet("")), the value is ignored internally and gtidSet remains null.

However, in the MariaDB-specific streaming path (requestBinaryLogStreamMaria()), the code assumes that gtidSet is always non-null and directly invokes gtidSet.toString(). This results in a NullPointerException during startup.

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Root Cause

• Empty GTID string passed via setGtidSet("")
• Empty string is ignored internally
• gtidSet remains null
• MariaDB streaming path assumes non-null and calls toString()

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Expected Behavior

If the GTID set is empty or not available, the client should not attempt to use it.

Instead, it should:

• Skip execution of SET @slave_connect_state = ...
• Continue with binlog streaming without GTID initialization

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Proposed Fix

Add a null/empty check before using gtidSet in requestBinaryLogStreamMaria().

For example:

if (gtidSet != null && !gtidSet.toString().isEmpty()) {
// execute SET @slave_connect_state
}

This ensures the client behaves correctly when GTID is not available and avoids the NPE.

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Additional Context

This issue was encountered while using Debezium with MariaDB, where the connector may start without a valid GTID state.