This closes Avoid wrapping FlowFile Attributes Map in an UnmodifiableMap in the StandardFlowFileBuilder
@@ -319,7 +319,12 @@ public final class StandardFlowFileRecord implements FlowFile, FlowFileRecord {
bLineageIdentifiers.clear();
bPenaltyExpirationMs = specFlowFile.getPenaltyExpirationMillis();
bSize = specFlowFile.getSize();
- bAttributes = specFlowFile.getAttributes();
+ // If this is a StandardFlowFileRecord, access the attributes map directly. Do not use the
+ // getAttributes() method, because that will wrap the original in an UnmodifiableMap. As a result,
+ // a Processor that continually calls session.append() for instance will have a FlowFile whose attributes
+ // Map is wrapped thousands of times until it hits a StackOverflowError. We want the getter to return
+ // UnmodifiableMap, though, so that Processors cannot directly modify that Map.
+ bAttributes = specFlowFile instanceof StandardFlowFileRecord ? ((StandardFlowFileRecord) specFlowFile).attributes : specFlowFile.getAttributes();
bAttributesCopied = false;
bClaim = specFlowFile.getContentClaim();
bClaimOffset = specFlowFile.getContentClaimOffset();
