Github user mattyb149 commented on a diff in the pull request:
https://github.com/apache/nifi/pull/2706#discussion_r188696201
--- Diff:
nifi-nar-bundles/nifi-extension-utils/nifi-record-utils/nifi-avro-record-utils/src/main/java/org/apache/nifi/schema/access/SchemaAccessUtils.java
---
@@ -85,7 +85,7 @@
.description("Specifies the name of the branch to use when
looking up the schema in the Schema Registry property. " +
"If the chosen Schema Registry does not support
branching, this value will be ignored.")
.addValidator(StandardValidators.NON_EMPTY_VALIDATOR)
- .expressionLanguageSupported(true)
+
.expressionLanguageSupported(ExpressionLanguageScope.VARIABLE_REGISTRY)
--- End diff --
Can't SCHEMA_BRANCH_NAME and SCHEMA_VERSION possibly evaluate EL using
FlowFile attributes like SCHEMA_NAME (from
[SchemaNamePropertyStrategy](https://github.com/apache/nifi/blob/master/nifi-nar-bundles/nifi-extension-utils/nifi-record-utils/nifi-standard-record-utils/src/main/java/org/apache/nifi/schema/access/SchemaNamePropertyStrategy.java#L62))?
I traced the calls back to
[RecordReaderFactory](https://github.com/apache/nifi/blob/master/nifi-nar-bundles/nifi-standard-services/nifi-record-serialization-service-api/src/main/java/org/apache/nifi/serialization/RecordReaderFactory.java#L46),
where you _might_ have FlowFile attributes available.
---
