[kotlin2cpg] Emit control structure for throw statement (#5833)

Author: SuperUserDone

joern-cli/frontends/kotlin2cpg/src/main/scala/io/joern/kotlin2cpg/ast/AstCreator.scala

@@ -317,7 +317,8 @@ class AstCreator(
         Seq(astForStringTemplate(typedExpr, argIdxMaybe, argNameMaybe, annotations))
       case typedExpr: KtSuperExpression => Seq(astForSuperExpression(typedExpr, argIdxMaybe, argNameMaybe, annotations))
       case typedExpr: KtThisExpression  => Seq(astForThisExpression(typedExpr, argIdxMaybe, argNameMaybe, annotations))
-      case typedExpr: KtThrowExpression => Seq(astForUnknown(typedExpr, argIdxMaybe, argNameMaybe, annotations))
+      case typedExpr: KtThrowExpression =>
+        Seq(astForThrowExpression(typedExpr, argIdxMaybe, argNameMaybe, annotations))
       case typedExpr: KtTryExpression   => Seq(astForTry(typedExpr, argIdxMaybe, argNameMaybe, annotations))
       case typedExpr: KtWhenExpression  => Seq(astForWhen(typedExpr, argIdxMaybe, argNameMaybe, annotations))
       case typedExpr: KtWhileExpression => Seq(astForWhile(typedExpr, annotations))

joern-cli/frontends/kotlin2cpg/src/main/scala/io/joern/kotlin2cpg/ast/AstForStatementsCreator.scala

@@ -21,6 +21,7 @@ import org.jetbrains.kotlin.psi.KtIfExpression
 import org.jetbrains.kotlin.psi.KtNamedFunction
 import org.jetbrains.kotlin.psi.KtProperty
 import org.jetbrains.kotlin.psi.KtPsiUtil
+import org.jetbrains.kotlin.psi.KtThrowExpression
 import org.jetbrains.kotlin.psi.KtTryExpression
 import org.jetbrains.kotlin.psi.KtWhenConditionWithExpression
 import org.jetbrains.kotlin.psi.KtWhenEntry
@@ -522,6 +523,17 @@ trait AstForStatementsCreator(implicit withSchemaValidation: ValidationMode) {
     Ast(node)
   }
 
+  def astForThrowExpression(
+    expr: KtThrowExpression,
+    argIdxMaybe: Option[Int],
+    argNameMaybe: Option[String],
+    annotations: Seq[KtAnnotationEntry] = Seq()
+  ): Ast = {
+    val thrownValue = astsForExpression(expr.getThrownExpression, None)
+    val node        = controlStructureNode(expr, ControlStructureTypes.THROW, expr.getText)
+    Ast(node).withChildren(thrownValue)
+  }
+
   def astForBlock(
     expr: KtBlockExpression,
     argIdxMaybe: Option[Int],

joern-cli/frontends/kotlin2cpg/src/test/scala/io/joern/kotlin2cpg/querying/ControlStructureTests.scala

@@ -4,6 +4,7 @@ import io.joern.kotlin2cpg.testfixtures.KotlinCode2CpgFixture
 import io.shiftleft.codepropertygraph.generated.nodes.{Block, Call, ControlStructure, Identifier, Local}
 import io.shiftleft.codepropertygraph.generated.{ControlStructureTypes, DispatchTypes, Operators}
 import io.shiftleft.semanticcpg.language.*
+import io.shiftleft.codepropertygraph.generated.nodes.Literal
 
 class ControlStructureTests extends KotlinCode2CpgFixture(withOssDataflow = false) {
   "CPG for code with simple if-else" should {
@@ -212,6 +213,37 @@ class ControlStructureTests extends KotlinCode2CpgFixture(withOssDataflow = fals
     }
   }
 
+  "CPG for code with throw statement" should {
+    val cpg = code("""
+        |package mypkg
+        |
+        |fun main() {
+        |  throw RuntimeException("boom")
+        |}
+        |""".stripMargin)
+
+    "should contain a THROW control structure with the thrown expression as its child" in {
+      val List(throwNode: ControlStructure) = cpg.controlStructure.controlStructureType(ControlStructureTypes.THROW).l
+      throwNode.code shouldBe "throw RuntimeException(\"boom\")"
+
+      // Ctor calls cause the following structure to be emitted for the call to RuntimeException
+      // throw Block {
+      //  var tmp = operator.<alloc>(...)
+      //  RuntimeException.<init>(tmp, "boom")
+      // }
+      val List(throwBlock: Block) = throwNode.astChildren.l
+      inside(throwBlock.astChildren.isCall.sortBy(_.name).l) { case List(init: Call, assignment: Call) =>
+        // Not really testing ctor generation, just a simple check that it does exist and has expected values
+        assignment.name shouldBe "<operator>.assignment"
+
+        init.code shouldBe "RuntimeException(\"boom\")"
+        init.name shouldBe "<init>"
+        init.methodFullName shouldBe "java.lang.RuntimeException.<init>:void(java.lang.String)"
+      }
+
+    }
+  }
+
   "CPG for code with `for-in` loop which has a simple variable loop parameter" should {
     val cpg = code("""
         |package mypkg