Fix direct assigning of fields with private type #731 (#735)

Author: volivan239

utbot-framework/src/main/kotlin/org/utbot/framework/assemble/AssembleModelGenerator.kt

@@ -6,6 +6,7 @@ import org.utbot.engine.ResolvedModels
 import org.utbot.engine.isPrivate
 import org.utbot.engine.isPublic
 import org.utbot.framework.UtSettings
+import org.utbot.framework.codegen.model.util.isAccessibleFrom
 import org.utbot.framework.modifications.AnalysisMode.SettersAndDirectAccessors
 import org.utbot.framework.modifications.ConstructorAnalyzer
 import org.utbot.framework.modifications.ConstructorAssembleInfo
@@ -255,6 +256,11 @@ class AssembleModelGenerator(private val methodUnderTest: UtMethod<*>) {
                     if (fieldId.isFinal) {
                         throw AssembleException("Final field $fieldId can't be set in an object of the class $classId")
                     }
+                    if (!fieldId.type.isAccessibleFrom(methodPackageName)) {
+                        throw AssembleException(
+                            "Field $fieldId can't be set in an object of the class $classId because its type is inaccessible"
+                        )
+                    }
                     //fill field value if it hasn't been filled by constructor, and it is not default
                     if (fieldId in constructorInfo.affectedFields ||
                             (fieldId !in constructorInfo.setFields && !fieldModel.hasDefaultValue())

utbot-framework/src/test/kotlin/org/utbot/examples/codegen/ClassWithStaticAndInnerClassesTest.kt

@@ -97,6 +97,15 @@ internal class ClassWithStaticAndInnerClassesTest : UtValueTestCaseChecker(testC
         )
     }
 
+    @Test
+    fun testGetValueFromPublicFieldWithPrivateType() {
+        check(
+            ClassWithStaticAndInnerClasses::getValueFromPublicFieldWithPrivateType,
+            eq(2),
+            coverage = DoNotCalculate
+        )
+    }
+
     @Test
     fun testPublicStaticClassWithPrivateField_DeepNestedStatic_g() {
         checkAllCombinations(

utbot-sample/src/main/java/org/utbot/examples/codegen/ClassWithStaticAndInnerClasses.java

@@ -3,6 +3,9 @@
 public class ClassWithStaticAndInnerClasses {
     public int z = 0;
 
+    // public field that exposes private type PrivateInnerClassWithPublicField
+    public PrivateInnerClassWithPublicField publicFieldWithPrivateType = new PrivateInnerClassWithPublicField(0);
+
     private static class PrivateStaticClassWithPublicField {
         public int x;
 
@@ -239,4 +242,8 @@ PackagePrivateFinalInnerClassWithPackagePrivateField usePackagePrivateFinalInner
 
         return innerClass.createFromIncrement(x);
     }
+
+    int getValueFromPublicFieldWithPrivateType() {
+        return publicFieldWithPrivateType.x;
+    }
 }