[kotlin2cpg] Structured ClosureBindingId (#5682)

* feat: improve closureBindingId value

* fix: include node name in closureBindingId

* fix: resolve test

---------

Co-authored-by: Tebogo Selahle <[email protected]>

Author: TNSelahle

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

@@ -212,10 +212,6 @@ class AstCreator(
     }
   }
 
-  protected def stringForUUID(node: KtExpression, name: String, typeFullName: String): String = {
-    node.getText + node.getContainingKtFile.getName + node.getContainingKtFile.getPackageFqName.toString + name + typeFullName
-  }
-
   protected def ktTokenToOperator(forPostfixExpr: Boolean): PartialFunction[KtToken, String] = {
     val postfixKtTokenToOperator: PartialFunction[KtToken, String] = {
       case KtTokens.EXCLEXCL   => Operators.notNullAssert

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

@@ -26,7 +26,6 @@ import org.jetbrains.kotlin.resolve.sam.SamConstructorDescriptor
 import org.jetbrains.kotlin.resolve.sam.SamConversionResolverImplKt
 import org.jetbrains.kotlin.resolve.source.KotlinSourceElement
 
-import java.util.UUID.nameUUIDFromBytes
 import scala.collection.mutable
 import scala.jdk.CollectionConverters.*
 
@@ -294,8 +293,7 @@ trait AstForFunctionsCreator(implicit withSchemaValidation: ValidationMode) {
         case node: NewLocal             => NodeContext(node, node.name, node.typeFullName)
       }
       .map { capturedNodeContext =>
-        val uuidBytes        = stringForUUID(fn, capturedNodeContext.name, capturedNodeContext.typeFullName)
-        val closureBindingId = nameUUIDFromBytes(uuidBytes.getBytes).toString
+        val closureBindingId = s"$descFullName.${capturedNodeContext.name}"
         val closureBinding   = closureBindingNode(closureBindingId, EvaluationStrategies.BY_REFERENCE)
         (closureBinding, capturedNodeContext)
       }
@@ -397,8 +395,7 @@ trait AstForFunctionsCreator(implicit withSchemaValidation: ValidationMode) {
         case node: NewLocal             => NodeContext(node, node.name, node.typeFullName)
       }
       .map { capturedNodeContext =>
-        val uuidBytes        = stringForUUID(expr, capturedNodeContext.name, capturedNodeContext.typeFullName)
-        val closureBindingId = nameUUIDFromBytes(uuidBytes.getBytes).toString
+        val closureBindingId = s"$descFullName.${capturedNodeContext.name}"
         val closureBinding   = closureBindingNode(closureBindingId, EvaluationStrategies.BY_REFERENCE)
         (closureBinding, capturedNodeContext)
       }

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

@@ -25,7 +25,7 @@ class LambdaTests extends KotlinCode2CpgFixture(withOssDataflow = false, withDef
     "should contain a CLOSURE_BINDING node for the captured parameter with the correct props set" in {
       val List(cb) = cpg.closureBinding.l
       cb.evaluationStrategy shouldBe EvaluationStrategies.BY_REFERENCE
-      cb.closureBindingId should not be None
+      cb.closureBindingId shouldBe Some("f1.<lambda>0.p")
 
       cb._refOut.size shouldBe 1
       cb._methodParameterInViaRefOut.get.name shouldBe "p"
@@ -45,9 +45,12 @@ class LambdaTests extends KotlinCode2CpgFixture(withOssDataflow = false, withDef
 
   "CPG for code with a simple lambda which captures a local" should {
     val cpg = code("""
-        |fun foo(x: String) {
-        |    val baz: String = "BAZ"
-        |    1.let { println(baz) }
+        |package simple.pkg
+        |class Bar {
+        |   fun foo(x: String) {
+        |     val baz: String = "BAZ"
+        |     1.let { println(baz) }
+        |   }
         |}
         |""".stripMargin)
 
@@ -57,8 +60,16 @@ class LambdaTests extends KotlinCode2CpgFixture(withOssDataflow = false, withDef
       mr.code should not be null
     }
 
-    "should contain two CAPTURE edges for the METHOD_REF" in {
-      cpg.methodRef.outE.collectAll[Capture].size shouldBe 2
+    "should contain three CAPTURE edges for the METHOD_REF" in {
+      cpg.methodRef.outE.collectAll[Capture].size shouldBe 3
+    }
+
+    "should contain a LOCAL node for the captured `this`" in {
+      cpg.local.code("this").size shouldBe 1
+    }
+
+    "should contain a LOCAL node for the captured `x`" in {
+      cpg.local.code("x").size shouldBe 1
     }
 
     "should contain a LOCAL node for the captured `baz`" in {
@@ -68,7 +79,23 @@ class LambdaTests extends KotlinCode2CpgFixture(withOssDataflow = false, withDef
     "should contain a CLOSURE_BINDING node for captured `baz` with the correct props set" in {
       val List(cb) = cpg.closureBinding.filter(_._localViaRefOut.name.l == List("baz")).l
       cb.evaluationStrategy shouldBe EvaluationStrategies.BY_REFERENCE
-      cb.closureBindingId should not be None
+      cb.closureBindingId shouldBe Some("simple.pkg.Bar.foo.<lambda>0.baz")
+
+      cb._refOut.size shouldBe 1
+    }
+
+    "should contain a CLOSURE_BINDING node for captured `x` with the correct props set" in {
+      val List(cb) = cpg.closureBinding.filter(_._methodParameterInViaRefOut.name.l == List("x")).l
+      cb.evaluationStrategy shouldBe EvaluationStrategies.BY_REFERENCE
+      cb.closureBindingId shouldBe Some("simple.pkg.Bar.foo.<lambda>0.x")
+
+      cb._refOut.size shouldBe 1
+    }
+
+    "should contain a CLOSURE_BINDING node for captured `this` with the correct props set" in {
+      val List(cb) = cpg.closureBinding.filter(_._methodParameterInViaRefOut.name.l == List("this")).l
+      cb.evaluationStrategy shouldBe EvaluationStrategies.BY_REFERENCE
+      cb.closureBindingId shouldBe Some("simple.pkg.Bar.foo.<lambda>0.this")
 
       cb._refOut.size shouldBe 1
     }