Codegen unable to properly instantiate public inner classes #761 (#1009)

Author: Markoutte

utbot-fuzzers/src/main/kotlin/org/utbot/fuzzer/providers/ObjectModelProvider.kt

@@ -48,8 +48,11 @@ class ObjectModelProvider(
         parameterIndex: Int,
         classId: ClassId,
     ): Sequence<ModelConstructor> = sequence {
-        if (unwantedConstructorsClasses.contains(classId) ||
-            classId.isPrimitiveWrapper || classId.isEnum || classId.isAbstract
+        if (unwantedConstructorsClasses.contains(classId)
+            || classId.isPrimitiveWrapper
+            || classId.isEnum
+            || classId.isAbstract
+            || (classId.isInner && !classId.isStatic)
         ) return@sequence
 
         val constructors = collectConstructors(classId) { javaConstructor ->

utbot-fuzzers/src/test/java/org/utbot/framework/plugin/api/samples/WithInnerClass.java

@@ -0,0 +1,19 @@
+package org.utbot.framework.plugin.api.samples;
+
+public class WithInnerClass {
+    public class NonStatic {
+        public int x;
+        public NonStatic(int x) { this.x = x; }
+    }
+    int f(NonStatic b) {
+        return b.x * b.x;
+    }
+
+    public static class Static {
+        public int x;
+        public Static(int x) { this.x = x; }
+    }
+    int g(Static b) {
+        return b.x * b.x;
+    }
+}

utbot-fuzzers/src/test/kotlin/org/utbot/framework/plugin/api/ModelProviderTest.kt

@@ -26,6 +26,7 @@ import org.utbot.framework.plugin.api.samples.FieldSetterClass
 import org.utbot.framework.plugin.api.samples.OuterClassWithEnums
 import org.utbot.framework.plugin.api.samples.PackagePrivateFieldAndClass
 import org.utbot.framework.plugin.api.samples.SampleEnum
+import org.utbot.framework.plugin.api.samples.WithInnerClass
 import org.utbot.framework.plugin.api.util.executableId
 import org.utbot.framework.plugin.api.util.primitiveByWrapper
 import org.utbot.framework.plugin.api.util.primitiveWrappers
@@ -561,6 +562,29 @@ class ModelProviderTest {
         }
     }
 
+    @Test
+    fun `no models are created for inner non-static class`() {
+        withUtContext(UtContext(this::class.java.classLoader)) {
+            val result = collect(
+                ObjectModelProvider(TestIdentityPreservingIdGenerator),
+                parameters = listOf(WithInnerClass.NonStatic::class.id)
+            )
+            assertEquals(0, result.size)
+        }
+    }
+
+    @Test
+    fun `some models are created for inner static class`() {
+        withUtContext(UtContext(this::class.java.classLoader)) {
+            val result = collect(
+                ObjectModelProvider(TestIdentityPreservingIdGenerator),
+                parameters = listOf(WithInnerClass.Static::class.id)
+            )
+            assertEquals(1, result.size)
+            assertTrue(result[0]!!.isNotEmpty())
+        }
+    }
+
     private enum class OneTwoThree {
         ONE, TWO, THREE
     }