Fix the way of setting static final fields

utbot-core/build.gradle

@@ -7,6 +7,8 @@ apply from: "${parent.projectDir}/gradle/include/jvm-project.gradle"
 dependencies {
     implementation group: 'io.github.microutils', name: 'kotlin-logging', version: kotlin_logging_version
     implementation group: 'net.java.dev.jna', name: 'jna-platform', version: '5.5.0'
+
+    testImplementation group: 'junit', name: 'junit', version: junit4_version
 }
 
 shadowJar {

utbot-core/src/main/kotlin/org/utbot/common/ReflectionUtil.kt

@@ -5,6 +5,7 @@ import java.lang.reflect.AccessibleObject
 import java.lang.reflect.Field
 import java.lang.reflect.Modifier
 import sun.misc.Unsafe
+import java.lang.reflect.Method
 
 object Reflection {
     val unsafe: Unsafe
@@ -15,15 +16,18 @@ object Reflection {
         unsafe = f.get(null) as Unsafe
     }
 
+    private val getDeclaredFields0Method: Method =
+        Class::class.java.getDeclaredMethod("getDeclaredFields0", Boolean::class.java).apply {
+            isAccessible = true
+        }
+
+    @Suppress("UNCHECKED_CAST")
+    private val fields: Array<Field> =
+        getDeclaredFields0Method.invoke(Field::class.java, false) as Array<Field>
 
     // TODO: works on JDK 8-17. Doesn't work on JDK 18
-    private val modifiersField: Field = run {
-        val getDeclaredFields0 = Class::class.java.getDeclaredMethod("getDeclaredFields0", Boolean::class.java)
-        getDeclaredFields0.isAccessible = true
-        @Suppress("UNCHECKED_CAST")
-        val fields = getDeclaredFields0.invoke(Field::class.java, false) as Array<Field>
+    private val modifiersField: Field =
         fields.first { it.name == "modifiers" }
-    }
 
     init {
         modifiersField.isAccessible = true
@@ -36,8 +40,9 @@ object Reflection {
 
 inline fun <R> AccessibleObject.withAccessibility(block: () -> R): R {
     val prevAccessibility = isAccessible
+    isAccessible = true
+
     try {
-        isAccessible = true
         return block()
     } finally {
         isAccessible = prevAccessibility
@@ -47,15 +52,24 @@ inline fun <R> AccessibleObject.withAccessibility(block: () -> R): R {
 /**
  * Executes given [block] with removed final modifier and restores it back after execution.
  * Also sets `isAccessible` to `true` and restores it back.
+ *
+ * Please note, that this function doesn't guarantee that reflection calls in the [block] always succeed. The problem is
+ * that prior calls to reflection may result in caching internal FieldAccessor field which is not suitable for setting
+ * [this]. But if you didn't call reflection previously, this function should help.
+ *
+ * Also note, that primitive static final fields may be inlined, so may not be possible to change.
  */
-inline fun<reified R> Field.withRemovedFinalModifier(block: () -> R): R {
+inline fun <reified R> Field.withAccessibility(block: () -> R): R {
     val prevModifiers = modifiers
+    val prevAccessibility = isAccessible
+
+    isAccessible = true
     setModifiers(this, modifiers and Modifier.FINAL.inv())
-    this.withAccessibility {
-        try {
-            return block()
-        } finally {
-            setModifiers(this, prevModifiers)
-        }
+
+    try {
+        return block()
+    } finally {
+        isAccessible = prevAccessibility
+        setModifiers(this, prevModifiers)
     }
 }

utbot-core/src/test/java/org/utbot/examples/reflection/ClassWithDifferentModifiers.java

@@ -0,0 +1,27 @@
+package org.utbot.examples.reflection;
+
+public class ClassWithDifferentModifiers {
+    @SuppressWarnings({"All"})
+    private int privateField;
+
+    private static final Wrapper privateStaticFinalField = new Wrapper(1);
+
+    public ClassWithDifferentModifiers() {
+        privateField = 0;
+    }
+
+    int packagePrivateMethod() {
+        return 1;
+    }
+
+    private int privateMethod() {
+        return 1;
+    }
+
+    public static class Wrapper {
+        public int x;
+        public Wrapper(int x) {
+            this.x = x;
+        }
+    }
+}

utbot-core/src/test/kotlin/org/utbot/common/ReflectionUtilTest.kt

@@ -0,0 +1,117 @@
+package org.utbot.common
+
+import org.junit.jupiter.api.Assertions.assertEquals
+import org.junit.jupiter.api.Assertions.assertNotNull
+import org.junit.jupiter.api.Test
+import org.utbot.examples.reflection.ClassWithDifferentModifiers
+import org.utbot.examples.reflection.ClassWithDifferentModifiers.Wrapper
+
+class ReflectionUtilTest {
+    private val testedClass = ClassWithDifferentModifiers::class.java
+
+    @Test
+    fun testPackagePrivateInvoke() {
+        val method = testedClass.declaredMethods.first { it.name == "packagePrivateMethod"}
+        val instance = ClassWithDifferentModifiers()
+
+        method.apply {
+            withAccessibility {
+                assertEquals(1, invoke(instance))
+            }
+        }
+    }
+
+    @Test
+    fun testPrivateInvoke() {
+        val method = testedClass.declaredMethods.first { it.name == "privateMethod"}
+        val instance = ClassWithDifferentModifiers()
+
+        method.apply {
+            withAccessibility {
+                assertEquals(1, invoke(instance))
+            }
+        }
+
+    }
+
+    @Test
+    fun testPrivateFieldSetting() {
+        val field = testedClass.declaredFields.first { it.name == "privateField" }
+        val instance = ClassWithDifferentModifiers()
+
+        field.apply {
+            withAccessibility {
+                set(instance, 0)
+            }
+        }
+    }
+
+    @Test
+    fun testPrivateFieldGetting() {
+        val field = testedClass.declaredFields.first { it.name == "privateField" }
+        val instance = ClassWithDifferentModifiers()
+
+        field.apply {
+            withAccessibility {
+                assertEquals(0, get(instance))
+            }
+        }
+
+    }
+
+    @Test
+    fun testPrivateFieldGettingAfterSetting() {
+        val field = testedClass.declaredFields.first { it.name == "privateField" }
+        val instance = ClassWithDifferentModifiers()
+
+
+        field.apply {
+            withAccessibility {
+                set(instance, 1)
+            }
+
+            withAccessibility {
+                assertEquals(1, get(instance))
+            }
+        }
+    }
+
+    @Test
+    fun testPrivateStaticFinalFieldSetting() {
+        val field = testedClass.declaredFields.first { it.name == "privateStaticFinalField" }
+
+        field.apply {
+            withAccessibility {
+                set(null, Wrapper(2))
+            }
+        }
+    }
+
+    @Test
+    fun testPrivateStaticFinalFieldGetting() {
+        val field = testedClass.declaredFields.first { it.name == "privateStaticFinalField" }
+
+        field.apply {
+            withAccessibility {
+                val value = get(null) as? Wrapper
+                assertNotNull(value)
+            }
+        }
+    }
+
+    @Test
+    fun testPrivateStaticFinalFieldGettingAfterSetting() {
+        val field = testedClass.declaredFields.first { it.name == "privateStaticFinalField" }
+
+        field.apply {
+            withAccessibility {
+                set(null, Wrapper(3))
+            }
+
+            withAccessibility {
+                val value = (get(null) as? Wrapper)?.x
+                assertEquals(3, value)
+            }
+        }
+    }
+}

utbot-framework/src/main/kotlin/org/utbot/framework/concrete/MethodMockController.kt

@@ -1,6 +1,6 @@
 package org.utbot.framework.concrete
 
-import org.utbot.common.withRemovedFinalModifier
+import org.utbot.common.withAccessibility
 import org.utbot.framework.plugin.api.util.signature
 import org.utbot.instrumentation.instrumentation.mock.MockConfig
 import java.lang.reflect.Field
@@ -36,7 +36,7 @@ class MethodMockController(
         isMockField = clazz.declaredFields.firstOrNull { it.name == MockConfig.IS_MOCK_FIELD + id }
             ?: error("No field ${MockConfig.IS_MOCK_FIELD + id} in $clazz")
 
-        isMockField.withRemovedFinalModifier {
+        isMockField.withAccessibility {
             isMockField.set(instance, true)
         }
 
@@ -46,7 +46,7 @@ class MethodMockController(
     }
 
     override fun close() {
-        isMockField.withRemovedFinalModifier {
+        isMockField.withAccessibility {
             isMockField.set(instance, false)
         }
     }

utbot-framework/src/main/kotlin/org/utbot/framework/concrete/UtExecutionInstrumentation.kt

@@ -3,7 +3,6 @@ package org.utbot.framework.concrete
 import org.utbot.common.StopWatch
 import org.utbot.common.ThreadBasedExecutor
 import org.utbot.common.withAccessibility
-import org.utbot.common.withRemovedFinalModifier
 import org.utbot.framework.UtSettings
 import org.utbot.framework.assemble.AssembleModelGenerator
 import org.utbot.framework.plugin.api.Coverage
@@ -260,7 +259,7 @@ object UtExecutionInstrumentation : Instrumentation<UtConcreteExecutionResult> {
         try {
             staticFields.forEach { (fieldId, value) ->
                 fieldId.field.run {
-                    withRemovedFinalModifier {
+                    withAccessibility {
                         savedFields[fieldId] = get(null)
                         set(null, value)
                     }
@@ -270,7 +269,7 @@ object UtExecutionInstrumentation : Instrumentation<UtConcreteExecutionResult> {
         } finally {
             savedFields.forEach { (fieldId, value) ->
                 fieldId.field.run {
-                    withRemovedFinalModifier {
+                    withAccessibility {
                         set(null, value)
                     }
                 }

utbot-instrumentation/src/main/kotlin/org/utbot/instrumentation/instrumentation/InvokeWithStaticsInstrumentation.kt

@@ -1,6 +1,6 @@
 package org.utbot.instrumentation.instrumentation
 
-import org.utbot.common.withRemovedFinalModifier
+import org.utbot.common.withAccessibility
 import org.utbot.framework.plugin.api.util.field
 import org.utbot.instrumentation.util.StaticEnvironment
 import java.lang.reflect.Field
@@ -47,7 +47,7 @@ class InvokeWithStaticsInstrumentation : Instrumentation<Result<*>> {
         staticEnvironment?.run {
             listOfFields.forEach { (fieldId, value) ->
                 fieldId.field.run {
-                    withRemovedFinalModifier {
+                    withAccessibility {
                         set(null, value)
                     }
                 }
@@ -75,14 +75,14 @@ class InvokeWithStaticsInstrumentation : Instrumentation<Result<*>> {
         init {
             val staticFields = clazz.declaredFields
                 .filter { checkField(it) } // TODO: think on this
-                .associate { it.name to it.withRemovedFinalModifier { it.get(null) } }
+                .associate { it.name to it.withAccessibility { it.get(null) } }
             savedFields = staticFields
         }
 
         fun restore() {
             clazz.declaredFields
                 .filter { checkField(it) }
-                .forEach { it.withRemovedFinalModifier { it.set(null, savedFields[it.name]) } }
+                .forEach { it.withAccessibility { it.set(null, savedFields[it.name]) } }
         }
     }
 }

utbot-instrumentation/src/main/kotlin/org/utbot/instrumentation/instrumentation/coverage/CoverageInstrumentation.kt

@@ -1,6 +1,6 @@
 package org.utbot.instrumentation.instrumentation.coverage
 
-import org.utbot.common.withRemovedFinalModifier
+import org.utbot.common.withAccessibility
 import org.utbot.instrumentation.ConcreteExecutor
 import org.utbot.instrumentation.Settings
 import org.utbot.instrumentation.instrumentation.ArgumentList
@@ -43,7 +43,7 @@ object CoverageInstrumentation : Instrumentation<Result<*>> {
         val visitedLinesField = clazz.fields.firstOrNull { it.name == probesFieldName }
             ?: throw NoProbesArrayException(clazz, Settings.PROBES_ARRAY_NAME)
 
-        return visitedLinesField.withRemovedFinalModifier {
+        return visitedLinesField.withAccessibility {
             invokeWithStatics.invoke(clazz, methodSignature, arguments, parameters)
         }
     }
@@ -57,7 +57,7 @@ object CoverageInstrumentation : Instrumentation<Result<*>> {
         val visitedLinesField = clazz.fields.firstOrNull { it.name == probesFieldName }
             ?: throw NoProbesArrayException(clazz, Settings.PROBES_ARRAY_NAME)
 
-        return visitedLinesField.withRemovedFinalModifier {
+        return visitedLinesField.withAccessibility {
             val visitedLines = visitedLinesField.get(null) as? BooleanArray
                 ?: throw CastProbesArrayException()
 
@@ -131,5 +131,5 @@ fun ConcreteExecutor<Result<*>, CoverageInstrumentation>.collectCoverage(clazz:
             is Protocol.ExceptionInChildProcess -> throw ChildProcessError(it.exception)
             else -> throw UnexpectedCommand(it)
         }
-    }!!
+    }
 }

utbot-instrumentation/src/test/kotlin/org/utbot/instrumentation/examples/mock/MockHelper.kt

@@ -1,6 +1,6 @@
 package org.utbot.instrumentation.examples.mock
 
-import org.utbot.common.withRemovedFinalModifier
+import org.utbot.common.withAccessibility
 import org.utbot.framework.plugin.api.util.signature
 import org.utbot.instrumentation.instrumentation.instrumenter.Instrumenter
 import org.utbot.instrumentation.instrumentation.mock.MockClassVisitor
@@ -58,7 +58,7 @@ class MockHelper(
         val isMockField = instrumentedClazz.getDeclaredField(MockConfig.IS_MOCK_FIELD + methodId)
         MockGetter.updateMocks(instance, method, mockedValues)
 
-        return isMockField.withRemovedFinalModifier {
+        return isMockField.withAccessibility {
             isMockField.set(instance, true)
             val res = block(instance)
             isMockField.set(instance, false)

utbot-instrumentation/src/test/kotlin/org/utbot/instrumentation/examples/mock/TestConstructorMock.kt

@@ -1,6 +1,6 @@
 package org.utbot.instrumentation.examples.mock
 
-import org.utbot.common.withRemovedFinalModifier
+import org.utbot.common.withAccessibility
 import org.utbot.instrumentation.samples.mock.ClassForMockConstructor
 import org.junit.jupiter.api.Assertions.assertEquals
 import org.junit.jupiter.api.Assertions.assertNotEquals
@@ -11,11 +11,11 @@ import org.junit.jupiter.api.Test
 class TestConstructorMock {
     private fun checkFields(instance: Any, x: Int, s: String?) {
         val xField = instance::class.java.getDeclaredField("x")
-        xField.withRemovedFinalModifier {
+        xField.withAccessibility {
             assertEquals(x, xField.getInt(instance))
         }
         val sField = instance::class.java.getDeclaredField("s")
-        sField.withRemovedFinalModifier {
+        sField.withAccessibility {
             assertEquals(s, sField.get(instance))
         }
     }