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https://issues.apache.org/jira/browse/NIFI-6654?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16928600#comment-16928600
]
Ron Chittaro commented on NIFI-6654:
------------------------------------
Meant to add, the problem is down in the RecordData.equals() where ultimately 2
schemas are compared, when they are self referential this is endless recursion:
{quote}@Override
public boolean equals(final Object obj) {
if (obj == this) {
return true;
}
if (obj == null) {
return false;
}
if (!(obj instanceof RecordDataType)) {
return false;
}
final RecordDataType other = (RecordDataType) obj;
*return Objects.equals(childSchema, other.childSchema);*
}
{quote}
> Stack overflow with self referencing avro schema
> ------------------------------------------------
>
> Key: NIFI-6654
> URL: https://issues.apache.org/jira/browse/NIFI-6654
> Project: Apache NiFi
> Issue Type: Bug
> Components: Core Framework
> Affects Versions: 1.9.2
> Reporter: Ron Chittaro
> Priority: Major
> Fix For: 1.10.0
>
>
> We (and our customers, thus why I marked this a blocker as we cannot proceed
> with 1.9.2 and in some cases product depolyment at all) have run into a stack
> overflow exception with the 'UpdateRecord' processor when upgrading from Nifi
> 1.7 to 1.9.2. I did some digging and it happens when:
> * A schema comparison operation is performed, AND
> * the schema in question is self referential
> I was a bit confused initially as I found that a unit test case for this
> already existed and was passing when I checked out and built 1.9.2. The test
> case is:
> {quote}testHashCodeAndEqualsWithSelfReferencingSchema() from
> TestSimpleRecordSchema.java located in:
> nifi\nifi-commons\nifi-record\src\test\java\org\apache\nifi\serialization
> {quote}
> However, if you dig a bit into this test case it is passing because the two
> schemas being compared contain the same memory references for the fields
> within them, thus comparisons do not exercise completely the underlying
> equals() operators of the objects contained in the schema. See bold below:
> {quote}final SimpleRecordSchema schema = new
> SimpleRecordSchema(SchemaIdentifier.EMPTY);
> final List<RecordField> personFields = new ArrayList<>();
> personFields.add(new RecordField("name",
> RecordFieldType.STRING.getDataType()));
> personFields.add(new RecordField("sibling",
> RecordFieldType.RECORD.getRecordDataType(schema)));
> *schema.setFields(personFields);*
> schema.hashCode();
> assertTrue(schema.equals(schema));
> final SimpleRecordSchema secondSchema = new
> SimpleRecordSchema(SchemaIdentifier.EMPTY);
> *secondSchema.setFields(personFields);*
> assertTrue(schema.equals(secondSchema));
> assertTrue(secondSchema.equals(schema));
> {quote}
>
> To reproduce the stack overflow I wrote the following test cases which I
> believe behaves more like it would in the 'UpdateProcessor' (or anywhere else
> a schema comparison is happening) where the schema object and all objects
> within are completely different memory references.
>
> {quote}@Test
> public void testSchemaCompareSelfRef() {
> // Set up first schema
> final SimpleRecordSchema personSchema = new
> SimpleRecordSchema(SchemaIdentifier.EMPTY);
> final List<RecordField> personFields = new ArrayList<>();
> personFields.add(new RecordField("name",
> RecordFieldType.STRING.getDataType()));
> personFields.add(new RecordField("address",
> RecordFieldType.STRING.getDataType()));
> personFields.add(new RecordField("SIN",
> RecordFieldType.STRING.getDataType()));
> personFields.add(new RecordField("PersonalData",
> RecordFieldType.RECORD.getRecordDataType(personSchema)));
> personSchema.setFields(personFields);
> // Set up second schema. Must be completely separate set of objects
> otherwise overloaded comparison
> // operators (particularly that from the SimpleRecordSchema class) will not
> be called.
> SimpleRecordSchema secondSchema = new
> SimpleRecordSchema(SchemaIdentifier.EMPTY);
> personFields.clear();
> personFields.add(new RecordField("name",
> RecordFieldType.STRING.getDataType()));
> personFields.add(new RecordField("address",
> RecordFieldType.STRING.getDataType()));
> personFields.add(new RecordField("SIN",
> RecordFieldType.STRING.getDataType()));
> personFields.add(new RecordField("PersonalData",
> RecordFieldType.RECORD.getRecordDataType(secondSchema)));
> secondSchema.setFields(personFields);
> assertTrue(personSchema.equals(secondSchema));
> }
> {quote}
>
>
>
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