Make standard library locations consistent between Java and Kotlin

java/kotlin-extractor/src/main/kotlin/utils/ClassNames.kt

@@ -1,5 +1,6 @@
 package com.github.codeql
 
+import com.intellij.openapi.vfs.StandardFileSystems
 import org.jetbrains.kotlin.ir.declarations.IrClass
 import org.jetbrains.kotlin.ir.declarations.IrDeclaration
 import org.jetbrains.kotlin.ir.declarations.IrDeclarationParent
@@ -45,9 +46,15 @@ fun getIrClassVirtualFile(irClass: IrClass): VirtualFile? {
     return null
 }
 
-fun getRawIrClassBinaryPath(irClass: IrClass): String? {
-  return getIrClassVirtualFile(irClass)?.getPath()
-}
+fun getRawIrClassBinaryPath(irClass: IrClass) =
+    getIrClassVirtualFile(irClass)?.let {
+        val path = it.path
+        if(it.fileSystem.protocol == StandardFileSystems.JRT_PROTOCOL)
+            // For JRT files, which we assume to be the JDK, hide the containing JAR path to match the Java extractor's behaviour.
+            "/${path.split("!/", limit = 2)[1]}"
+        else
+            path
+    }
 
 fun getIrClassBinaryPath(irClass: IrClass): String {
   return getRawIrClassBinaryPath(irClass)

java/ql/test/kotlin/library-tests/mixed-java-and-kotlin/Q.java

@@ -0,0 +1,3 @@
+package main;
+
+public class Q {}

java/ql/test/kotlin/library-tests/mixed-java-and-kotlin/W.kt

@@ -0,0 +1,3 @@
+package main
+
+class W {}

java/ql/test/kotlin/library-tests/mixed-java-and-kotlin/test.expected

@@ -0,0 +1,2 @@
+| Q.java:0:0:0:0 | Q |
+| W.kt:0:0:0:0 | W |

java/ql/test/kotlin/library-tests/mixed-java-and-kotlin/test.ql

@@ -0,0 +1,7 @@
+import java
+
+from File f
+where f.getExtension() in ["java", "kt"]
+select f
+
+// This test is mainly a consistency test; just checking that both the Java and Kotlin source were extracted here