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[codegen] Fix equaliser treating null array elements and map values as unequal #9860

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Merged
JingsongLi merged 1 commit into from
Sep 17, 2026
+92 −3
Merged

[codegen] Fix equaliser treating null array elements and map values as unequal #9860

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17 changes: 14 additions & 3 deletions paimon-codegen/src/main/scala/org/apache/paimon/codegen/ScalarOperatorGens.scala
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Original file line number Diff line number Diff line change
Expand Up @@ -272,7 +272,7 @@ object ScalarOperatorGens {
| }
|
| ${elementEqualsExpr.code}
| if (!${elementEqualsExpr.resultTerm}) {
| if (!${nullSafeEquals(leftElementNullTerm, rightElementNullTerm, elementEqualsExpr.resultTerm)}) {
| $resultTerm = false;
| break;
| }
Expand Down Expand Up @@ -396,7 +396,7 @@ object ScalarOperatorGens {
| }
|
| ${valueEqualsExpr.code}
| if (${valueEqualsExpr.resultTerm}) {
| if (${nullSafeEquals(leftValueNullTerm, rightValueNullTerm, valueEqualsExpr.resultTerm)}) {
| $matchedTerm[$rightIndexTerm] = true;
| $foundTerm = true;
| }
Expand Down Expand Up @@ -432,7 +432,7 @@ object ScalarOperatorGens {
| boolean $rightValueNullTerm = ($rightValueTerm == null);
|
| ${valueEqualsExpr.code}
| if (!${valueEqualsExpr.resultTerm}) {
| if (!${nullSafeEquals(leftValueNullTerm, rightValueNullTerm, valueEqualsExpr.resultTerm)}) {
| $resultTerm = false;
| break;
| }
Expand Down Expand Up @@ -464,6 +464,17 @@ object ScalarOperatorGens {
}
}

/**
* Null-safe equality on a nested element or value: two nulls are equal, a single null is not,
* otherwise the generated equality decides. `generateEquals` leaves its result flag `false` when
* either operand is null, so reading that flag alone treats two null elements as unequal.
*/
private def nullSafeEquals(
leftNullTerm: String,
rightNullTerm: String,
equalsTerm: String): String =
s"(($leftNullTerm && $rightNullTerm) || (!$leftNullTerm && !$rightNullTerm && $equalsTerm))"

private def containsFloatingPoint(t: DataType): Boolean = t.getTypeRoot match {
case FLOAT | DOUBLE => true
case DataTypeRoot.ARRAY | DataTypeRoot.MAP | DataTypeRoot.MULTISET | DataTypeRoot.ROW |
Expand Down
78 changes: 78 additions & 0 deletions paimon-codegen/src/test/java/org/apache/paimon/codegen/EqualiserCodeGeneratorTest.java
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Expand Up @@ -571,6 +571,84 @@ public void testIntKeyMapEqualiserIgnoresEntryOrder() {
false);
}

@Test
public void testArrayEqualiserTreatsNullElementsAsEqual() {
DataType intArrayType = DataTypes.ARRAY(DataTypes.INT());
RecordEqualiser intArrayEqualiser =
new EqualiserCodeGenerator(new DataType[] {intArrayType})
.generateRecordEqualiser("nullElementIntArrayFieldEquals")
.newInstance(Thread.currentThread().getContextClassLoader());
assertFloatingPointEqualiser(
intArrayEqualiser,
intArrayType,
new GenericArray(new Object[] {1, null}),
new GenericArray(new Object[] {1, null}),
true);
assertFloatingPointEqualiser(
intArrayEqualiser,
intArrayType,
new GenericArray(new Object[] {1, null}),
new GenericArray(new Object[] {1, 2}),
false);

DataType doubleArrayType = DataTypes.ARRAY(DataTypes.DOUBLE());
RecordEqualiser doubleArrayEqualiser =
new EqualiserCodeGenerator(new DataType[] {doubleArrayType})
.generateRecordEqualiser("nullElementDoubleArrayFieldEquals")
.newInstance(Thread.currentThread().getContextClassLoader());
assertFloatingPointEqualiser(
doubleArrayEqualiser,
doubleArrayType,
new GenericArray(new Object[] {1.0d, null}),
new GenericArray(new Object[] {1.0d, null}),
true);

DataType rowArrayType = DataTypes.ARRAY(DataTypes.ROW(DataTypes.INT()));
RecordEqualiser rowArrayEqualiser =
new EqualiserCodeGenerator(new DataType[] {rowArrayType})
.generateRecordEqualiser("nullElementRowArrayFieldEquals")
.newInstance(Thread.currentThread().getContextClassLoader());
assertFloatingPointEqualiser(
rowArrayEqualiser,
rowArrayType,
new GenericArray(new Object[] {null}),
new GenericArray(new Object[] {null}),
true);
}

@Test
public void testMapEqualiserTreatsNullValuesAsEqual() {
DataType intKeyMapType = DataTypes.MAP(DataTypes.INT(), DataTypes.INT());
RecordEqualiser intKeyMapEqualiser =
new EqualiserCodeGenerator(new DataType[] {intKeyMapType})
.generateRecordEqualiser("nullValueIntKeyMapFieldEquals")
.newInstance(Thread.currentThread().getContextClassLoader());
assertMapEqualiser(
intKeyMapEqualiser,
intKeyMapType,
new GenericMap(singletonMap(1, null)),
new GenericMap(singletonMap(1, null)),
true);
assertMapEqualiser(
intKeyMapEqualiser,
intKeyMapType,
new GenericMap(singletonMap(1, null)),
new GenericMap(singletonMap(1, 2)),
false);

DataType binaryKeyMapType = DataTypes.MAP(DataTypes.BYTES(), DataTypes.INT());
RecordEqualiser binaryKeyMapEqualiser =
new EqualiserCodeGenerator(new DataType[] {binaryKeyMapType})
.generateRecordEqualiser("nullValueBinaryKeyMapFieldEquals")
.newInstance(Thread.currentThread().getContextClassLoader());
assertMapEqualiser(
binaryKeyMapEqualiser,
binaryKeyMapType,
new GenericMap(singletonMap("k".getBytes(), null)),
new GenericMap(singletonMap("k".getBytes(), null)),
true);
}

private static Map<Object, Object> singletonMap(Object key, Object value) {
Map<Object, Object> map = new HashMap<>();
map.put(key, value);
Expand Down
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