Merge pull request #10328 from tamasvajk/kotlin-kfunction-fix

Kotlin: fix `KFunctionX.invoke` extraction

Author: tamasvajk

java/kotlin-extractor/src/main/kotlin/KotlinFileExtractor.kt

@@ -1333,6 +1333,14 @@ open class KotlinFileExtractor(
         val receiverClass = receiverType.classifier.owner as? IrClass ?: return listOf()
         val ancestorTypes = ArrayList<IrSimpleType>()
 
+        // KFunctionX doesn't implement FunctionX on versions before 1.7.0:
+        if ((callTarget.name.asString() == "invoke") &&
+            (receiverClass.fqNameWhenAvailable?.asString()?.startsWith("kotlin.reflect.KFunction") == true) &&
+            (callTarget.parentClassOrNull?.fqNameWhenAvailable?.asString()?.startsWith("kotlin.Function") == true)
+        ) {
+            return receiverType.arguments
+        }
+
         // Populate ancestorTypes with the path from receiverType's class to its ancestor, callTarget's declaring type.
         fun walkFrom(c: IrClass): Boolean {
             if(declaringType == c)

java/ql/integration-tests/posix-only/kotlin/kotlin_kfunction/app/build.gradle

@@ -0,0 +1,25 @@
+/*
+ * This file was generated by the Gradle 'init' task.
+ *
+ * This generated file contains a sample Kotlin application project to get you started.
+ * For more details take a look at the 'Building Java & JVM projects' chapter in the Gradle
+ * User Manual available at https://docs.gradle.org/7.0.2/userguide/building_java_projects.html
+ */
+
+plugins {
+    // Apply the org.jetbrains.kotlin.jvm Plugin to add support for Kotlin.
+    id 'org.jetbrains.kotlin.jvm' version '1.6.20'
+
+    // Apply the application plugin to add support for building a CLI application in Java.
+    id 'application'
+}
+
+repositories {
+    // Use Maven Central for resolving dependencies.
+    mavenCentral()
+}
+
+application {
+    // Define the main class for the application.
+    mainClass = 'testProject.AppKt'
+}

java/ql/integration-tests/posix-only/kotlin/kotlin_kfunction/app/src/main/kotlin/testProject/App.kt

@@ -0,0 +1,10 @@
+import kotlin.reflect.*
+
+fun fn() {
+    val ref: KFunction2<Ccc, Int, Double> = Ccc::m
+    ref.invoke(Ccc(), 1)
+}
+
+class Ccc {
+    fun m(i:Int):Double = 5.0
+}

java/ql/integration-tests/posix-only/kotlin/kotlin_kfunction/diagnostics.expected

@@ -0,0 +1,4 @@
+import java
+import semmle.code.java.Diagnostics
+
+query predicate diag(Diagnostic d) { any() }

java/ql/integration-tests/posix-only/kotlin/kotlin_kfunction/diagnostics.ql

@@ -0,0 +1,11 @@
+/*
+ * This file was generated by the Gradle 'init' task.
+ *
+ * The settings file is used to specify which projects to include in your build.
+ *
+ * Detailed information about configuring a multi-project build in Gradle can be found
+ * in the user manual at https://docs.gradle.org/7.0.2/userguide/multi_project_builds.html
+ */
+
+rootProject.name = 'testProject'
+include('app')

java/ql/integration-tests/posix-only/kotlin/kotlin_kfunction/settings.gradle

@@ -0,0 +1,5 @@
+from create_database_utils import *
+
+run_codeql_database_create(
+    ["gradle build --no-daemon --no-build-cache --rerun-tasks"], lang="java")
+runSuccessfully(["gradle", "clean"])