Forbid mocking WeakReference with inline mock maker (#3759)

jselbo · Joshua Selbo · web-flow · commit 58ba4455209a · 2025-10-31T16:40:36.000+01:00
Fixes #3758 Co-authored-by: Joshua Selbo <jselbo@meta.com>
diff --git a/mockito-core/src/main/java/org/mockito/internal/creation/bytebuddy/InlineBytecodeGenerator.java b/mockito-core/src/main/java/org/mockito/internal/creation/bytebuddy/InlineBytecodeGenerator.java
@@ -36,6 +36,7 @@
 import java.lang.instrument.ClassFileTransformer;
 import java.lang.instrument.Instrumentation;
 import java.lang.instrument.UnmodifiableClassException;
+import java.lang.ref.WeakReference;
 import java.lang.reflect.Method;
 import java.lang.reflect.Modifier;
 import java.security.ProtectionDomain;
@@ -65,7 +66,8 @@ public class InlineBytecodeGenerator implements BytecodeGenerator, ClassFileTran
                             Long.class,
                             Float.class,
                             Double.class,
-                            String.class));
+                            String.class,
+                            WeakReference.class));
 
     private final Instrumentation instrumentation;
 
diff --git a/mockito-core/src/main/java/org/mockito/internal/creation/bytebuddy/InlineDelegateByteBuddyMockMaker.java b/mockito-core/src/main/java/org/mockito/internal/creation/bytebuddy/InlineDelegateByteBuddyMockMaker.java
@@ -596,7 +596,7 @@ public String nonMockableReason() {
                     return "primitive type";
                 }
                 if (EXCLUDES.contains(type)) {
-                    return "Cannot mock wrapper types, String.class or Class.class";
+                    return "Cannot mock primitive wrapper types, String, Class, or WeakReference";
                 }
                 return "VM does not support modification of given type";
             }
diff --git a/mockito-core/src/test/java/org/mockito/internal/creation/bytebuddy/InlineDelegateByteBuddyMockMakerTest.java b/mockito-core/src/test/java/org/mockito/internal/creation/bytebuddy/InlineDelegateByteBuddyMockMakerTest.java
@@ -10,6 +10,7 @@
 import static org.junit.Assert.*;
 
 import java.io.IOException;
+import java.lang.ref.WeakReference;
 import java.util.*;
 import java.util.concurrent.Callable;
 import java.util.regex.Pattern;
@@ -369,7 +370,7 @@ public void should_handle_missing_or_inconsistent_stack_trace() {
     public void should_provide_reason_for_wrapper_class() {
         MockMaker.TypeMockability mockable = mockMaker.isTypeMockable(Integer.class);
         assertThat(mockable.nonMockableReason())
-                .isEqualTo("Cannot mock wrapper types, String.class or Class.class");
+                .isEqualTo("Cannot mock primitive wrapper types, String, Class, or WeakReference");
     }
 
     @Test
@@ -394,15 +395,23 @@ public void is_type_mockable_excludes_String() {
         MockMaker.TypeMockability mockable = mockMaker.isTypeMockable(String.class);
         assertThat(mockable.mockable()).isFalse();
         assertThat(mockable.nonMockableReason())
-                .contains("Cannot mock wrapper types, String.class or Class.class");
+                .contains("Cannot mock primitive wrapper types, String, Class, or WeakReference");
     }
 
     @Test
     public void is_type_mockable_excludes_Class() {
         MockMaker.TypeMockability mockable = mockMaker.isTypeMockable(Class.class);
         assertThat(mockable.mockable()).isFalse();
         assertThat(mockable.nonMockableReason())
-                .contains("Cannot mock wrapper types, String.class or Class.class");
+                .contains("Cannot mock primitive wrapper types, String, Class, or WeakReference");
+    }
+
+    @Test
+    public void is_type_mockable_excludes_WeakReference() {
+        MockMaker.TypeMockability mockable = mockMaker.isTypeMockable(WeakReference.class);
+        assertThat(mockable.mockable()).isFalse();
+        assertThat(mockable.nonMockableReason())
+                .contains("Cannot mock primitive wrapper types, String, Class, or WeakReference");
     }
 
     @Test

Original file line number	Diff line number	Diff line change
`@@ -596,7 +596,7 @@ public String nonMockableReason() {`
`596`	`596`	`return "primitive type";`
`597`	`597`	`}`
`598`	`598`	`if (EXCLUDES.contains(type)) {`
`599`		`- return "Cannot mock wrapper types, String.class or Class.class";`
	`599`	`+ return "Cannot mock primitive wrapper types, String, Class, or WeakReference";`
`600`	`600`	`}`
`601`	`601`	`return "VM does not support modification of given type";`
`602`	`602`	`}`