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Posted to commits@groovy.apache.org by pa...@apache.org on 2026/07/14 00:17:34 UTC
(groovy) 04/04: GROOVY-12154: box primitive lambda param when the target SAM param is a reference type
This is an automated email from the ASF dual-hosted git repository.
paulk-asert pushed a commit to branch GROOVY_5_0_X
in repository https://gitbox.apache.org/repos/asf/groovy.git
commit 1c49437ba60d0594550a00950aed2f69bdbd13ce
Author: Paul King <pa...@asert.com.au>
AuthorDate: Tue Jul 14 10:16:27 2026 +1000
GROOVY-12154: box primitive lambda param when the target SAM param is a reference type
A @CompileStatic lambda declaring a primitive parameter (e.g. (int a) -> ...)
against a generic functional interface (e.g. Function<Integer,Integer>)
compiled cleanly but threw at runtime:
java.lang.invoke.LambdaConversionException:
int is not a subtype of class java.lang.Object
AbstractFunctionalInterfaceWriter.convertParameterType always emitted a
primitive implementation-method parameter when the lambda declared a
primitive, ignoring the target (functional-interface) parameter type. But
LambdaMetafactory links against the erased SAM signature (Object) and will
not unbox to a primitive, so the implementation method must accept the boxed
type when the SAM parameter is a reference type. It stays primitive only when
the SAM parameter is itself primitive (e.g. IntUnaryOperator), preserving
GROOVY-9790.
Backport of 86c6648d1e from master.
---
.../asm/sc/AbstractFunctionalInterfaceWriter.java | 16 ++-
src/test/groovy/bugs/Groovy12154.groovy | 112 +++++++++++++++++++++
2 files changed, 123 insertions(+), 5 deletions(-)
diff --git a/src/main/java/org/codehaus/groovy/classgen/asm/sc/AbstractFunctionalInterfaceWriter.java b/src/main/java/org/codehaus/groovy/classgen/asm/sc/AbstractFunctionalInterfaceWriter.java
index ceb280c43b..d2017a76b1 100644
--- a/src/main/java/org/codehaus/groovy/classgen/asm/sc/AbstractFunctionalInterfaceWriter.java
+++ b/src/main/java/org/codehaus/groovy/classgen/asm/sc/AbstractFunctionalInterfaceWriter.java
@@ -116,12 +116,18 @@ public interface AbstractFunctionalInterfaceWriter {
ClassNode type;
if (isPrimitiveType(parameterType)) {
- if (!isPrimitiveType(inferredType)) {
- // The non-primitive type and primitive type are not allowed to mix since Java 9+
- // java.lang.invoke.LambdaConversionException: Type mismatch for instantiated parameter 0: class java.lang.Integer is not a subtype of int
- type = getUnwrapper(inferredType).getPlainNodeReference(false);
+ // The lambda parameter is declared with a primitive type; reduce the inferred type to it.
+ ClassNode primitive = isPrimitiveType(inferredType) ? inferredType : getUnwrapper(inferredType);
+ if (isPrimitiveType(targetType)) {
+ // The functional-interface parameter is itself primitive, so the implementation method
+ // stays primitive (GROOVY-9790: otherwise "Integer is not a subtype of int").
+ type = primitive.getPlainNodeReference(false);
} else {
- type = inferredType.getPlainNodeReference(false);
+ // GROOVY-12154: the functional-interface parameter is a reference type, so the
+ // implementation method must accept the BOXED type -- LambdaMetafactory links against
+ // the erased SAM signature (Object) and will not unbox to a primitive
+ // (java.lang.invoke.LambdaConversionException: int is not a subtype of class java.lang.Object).
+ type = getWrapper(primitive).getPlainNodeReference();
}
} else if (isPrimitiveType(inferredType)) {
// GROOVY-9790: bootstrap method initialization exception raised when lambda parameter type is wrong
diff --git a/src/test/groovy/bugs/Groovy12154.groovy b/src/test/groovy/bugs/Groovy12154.groovy
new file mode 100644
index 0000000000..489439a7d7
--- /dev/null
+++ b/src/test/groovy/bugs/Groovy12154.groovy
@@ -0,0 +1,112 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements. See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership. The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied. See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+package bugs
+
+import org.junit.jupiter.api.Test
+
+import static groovy.test.GroovyAssert.assertScript
+
+final class Groovy12154 {
+
+ // A lambda with a primitive-typed parameter targeting a generic functional interface used to
+ // compile cleanly but throw at runtime (LambdaConversionException: int is not a subtype of
+ // class java.lang.Object), because the implementation method kept the primitive parameter type
+ // while LambdaMetafactory links against the erased (reference) SAM signature.
+
+ @Test
+ void testPrimitiveParamTargetingGenericSam() {
+ assertScript '''
+ import java.util.function.Function
+ @groovy.transform.CompileStatic
+ class T {
+ Function<Integer, Integer> f = (int a) -> a * 2
+ Integer m() { f.apply(5) }
+ }
+ assert new T().m() == 10
+ '''
+ }
+
+ @Test
+ void testMultiplePrimitiveParamsTargetingGenericSam() {
+ assertScript '''
+ import java.util.function.BiFunction
+ @groovy.transform.CompileStatic
+ class T {
+ BiFunction<Integer, Integer, Integer> f = (int a, int b) -> a + b
+ List m() { [f.apply(1, 2), f.apply(5, 5)] }
+ }
+ assert new T().m() == [3, 10]
+ '''
+ }
+
+ @Test
+ void testPrimitiveParamWithDefaultTargetingGenericSam() {
+ assertScript '''
+ import java.util.function.BiFunction
+ @groovy.transform.CompileStatic
+ class T {
+ BiFunction<Integer, Integer, Integer> f = (int a, int b = 10) -> a + b
+ List m() { [f.apply(1, 2), f.apply(5, 5)] }
+ }
+ assert new T().m() == [3, 10]
+ '''
+ }
+
+ @Test
+ void testLongPrimitiveParamTargetingGenericSam() {
+ assertScript '''
+ import java.util.function.Function
+ @groovy.transform.CompileStatic
+ class T {
+ Function<Long, Long> f = (long a) -> a * 2L
+ Long m() { f.apply(5L) }
+ }
+ assert new T().m() == 10L
+ '''
+ }
+
+ // Regressions: a primitive-parameter functional interface must still use a primitive impl param.
+
+ @Test
+ void testPrimitiveParamTargetingPrimitiveSam() {
+ assertScript '''
+ import java.util.function.IntUnaryOperator
+ @groovy.transform.CompileStatic
+ class T {
+ IntUnaryOperator f = (int a) -> a * 2
+ int m() { f.applyAsInt(5) }
+ }
+ assert new T().m() == 10
+ '''
+ }
+
+ @Test
+ void testUntypedAndBoxedParamsUnaffected() {
+ assertScript '''
+ import java.util.function.Function
+ @groovy.transform.CompileStatic
+ class T {
+ Function<Integer, Integer> u = (a) -> a * 2
+ Function<Integer, Integer> b = (Integer a) -> a * 2
+ List m() { [u.apply(5), b.apply(5)] }
+ }
+ assert new T().m() == [10, 10]
+ '''
+ }
+}