Kotlin: Avoid infinite recursion when extracting recursive interfaces

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

@@ -1,5 +1,6 @@
 package com.github.codeql
 
+import com.github.codeql.utils.ClassInstanceStack
 import com.github.codeql.utils.isExternalFileClassMember
 import com.semmle.extractor.java.OdasaOutput
 import com.semmle.util.data.StringDigestor
@@ -18,6 +19,7 @@ class ExternalDeclExtractor(
     val compression: Compression,
     val invocationTrapFile: String,
     val sourceFilePath: String,
+    val classInstanceStack: ClassInstanceStack,
     val primitiveTypeMapping: PrimitiveTypeMapping,
     val pluginContext: IrPluginContext,
     val globalExtensionState: KotlinExtractorGlobalState,
@@ -163,6 +165,7 @@ class ExternalDeclExtractor(
                                 binaryPath,
                                 manager,
                                 this,
+                                classInstanceStack,
                                 primitiveTypeMapping,
                                 pluginContext,
                                 KotlinFileExtractor.DeclarationStack(),

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

@@ -1,5 +1,6 @@
 package com.github.codeql
 
+import com.github.codeql.utils.ClassInstanceStack
 import com.github.codeql.utils.versions.usesK2
 import com.semmle.util.files.FileUtil
 import com.semmle.util.trap.pathtransformers.PathTransformer
@@ -151,6 +152,7 @@ class KotlinExtractorExtension(
             }
             val compression = getCompression(logger)
 
+            val classInstanceStack = ClassInstanceStack()
             val primitiveTypeMapping = PrimitiveTypeMapping(logger, pluginContext)
             // FIXME: FileUtil expects a static global logger
             // which should be provided by SLF4J's factory facility. For now we set it here.
@@ -182,6 +184,7 @@ class KotlinExtractorExtension(
                     trapDir,
                     srcDir,
                     file,
+                    classInstanceStack,
                     primitiveTypeMapping,
                     pluginContext,
                     globalExtensionState
@@ -358,6 +361,7 @@ private fun doFile(
     dbTrapDir: File,
     dbSrcDir: File,
     srcFile: IrFile,
+    classInstanceStack: ClassInstanceStack,
     primitiveTypeMapping: PrimitiveTypeMapping,
     pluginContext: IrPluginContext,
     globalExtensionState: KotlinExtractorGlobalState
@@ -415,6 +419,7 @@ private fun doFile(
                         compression,
                         invocationTrapFile,
                         srcFilePath,
+                        classInstanceStack,
                         primitiveTypeMapping,
                         pluginContext,
                         globalExtensionState,
@@ -429,6 +434,7 @@ private fun doFile(
                         srcFilePath,
                         null,
                         externalDeclExtractor,
+                        classInstanceStack,
                         primitiveTypeMapping,
                         pluginContext,
                         KotlinFileExtractor.DeclarationStack(),

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

@@ -62,6 +62,7 @@ open class KotlinFileExtractor(
     val filePath: String,
     dependencyCollector: OdasaOutput.TrapFileManager?,
     externalClassExtractor: ExternalDeclExtractor,
+    classInstanceStack: ClassInstanceStack,
     primitiveTypeMapping: PrimitiveTypeMapping,
     pluginContext: IrPluginContext,
     val declarationStack: DeclarationStack,
@@ -72,6 +73,7 @@ open class KotlinFileExtractor(
         tw,
         dependencyCollector,
         externalClassExtractor,
+        classInstanceStack,
         primitiveTypeMapping,
         pluginContext,
         globalExtensionState
@@ -496,12 +498,17 @@ open class KotlinFileExtractor(
             }
 
             extractClassModifiers(c, id)
-            extractClassSupertypes(
-                c,
-                id,
-                if (argsIncludingOuterClasses == null) ExtractSupertypesMode.Raw
-                else ExtractSupertypesMode.Specialised(argsIncludingOuterClasses)
-            )
+            classInstanceStack.push(c)
+            try {
+                extractClassSupertypes(
+                    c,
+                    id,
+                    if (argsIncludingOuterClasses == null) ExtractSupertypesMode.Raw
+                    else ExtractSupertypesMode.Specialised(argsIncludingOuterClasses)
+                )
+            } finally {
+                classInstanceStack.pop()
+            }
 
             val locId = getLocation(c, argsIncludingOuterClasses)
             tw.writeHasLocation(id, locId)

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

@@ -49,6 +49,7 @@ open class KotlinUsesExtractor(
     open val tw: TrapWriter,
     val dependencyCollector: OdasaOutput.TrapFileManager?,
     val externalClassExtractor: ExternalDeclExtractor,
+    val classInstanceStack: ClassInstanceStack,
     val primitiveTypeMapping: PrimitiveTypeMapping,
     val pluginContext: IrPluginContext,
     val globalExtensionState: KotlinExtractorGlobalState
@@ -182,6 +183,7 @@ open class KotlinUsesExtractor(
                 filePath,
                 dependencyCollector,
                 externalClassExtractor,
+                classInstanceStack,
                 primitiveTypeMapping,
                 pluginContext,
                 newDeclarationStack,
@@ -199,6 +201,7 @@ open class KotlinUsesExtractor(
             clsFile.path,
             dependencyCollector,
             externalClassExtractor,
+            classInstanceStack,
             primitiveTypeMapping,
             pluginContext,
             newDeclarationStack,
@@ -537,6 +540,19 @@ open class KotlinUsesExtractor(
         return Pair(p?.first ?: c, p?.second ?: argsIncludingOuterClassesBeforeReplacement)
     }
 
+    private fun avoidInfiniteRecursion(
+        pair: Pair<IrClass, List<IrTypeArgument>?>
+    ): Pair<IrClass, List<IrTypeArgument>?> {
+        val c = pair.first
+        val args = pair.second
+        if (args != null && args.isNotEmpty() && classInstanceStack.possiblyCyclicExtraction(c, args)) {
+            logger.warn("Making use of ${c.name} a raw type to avoid infinite recursion")
+            return Pair(c, null)
+        } else {
+            return pair
+        }
+    }
+
     // `typeArgs` can be null to describe a raw generic type.
     // For non-generic types it will be zero-length list.
     private fun addClassLabel(
@@ -545,7 +561,7 @@ open class KotlinUsesExtractor(
         inReceiverContext: Boolean = false
     ): TypeResult<DbClassorinterface> {
         val replaced =
-            tryReplaceType(cBeforeReplacement, argsIncludingOuterClassesBeforeReplacement)
+            avoidInfiniteRecursion(tryReplaceType(cBeforeReplacement, argsIncludingOuterClassesBeforeReplacement))
         val replacedClass = replaced.first
         val replacedArgsIncludingOuterClasses = replaced.second
 

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

@@ -0,0 +1,47 @@
+package com.github.codeql.utils
+
+import java.util.Stack
+import org.jetbrains.kotlin.ir.declarations.IrClass
+import org.jetbrains.kotlin.ir.symbols.IrClassSymbol
+import org.jetbrains.kotlin.ir.types.*
+
+class ClassInstanceStack {
+    private val stack: Stack<IrClass> = Stack()
+
+    fun push(c: IrClass) = stack.push(c)
+    fun pop() = stack.pop()
+
+    private fun checkTypeArgs(sym: IrClassSymbol, args: List<IrTypeArgument>): Boolean {
+        for (arg in args) {
+            if (arg is IrTypeProjection) {
+                if (checkType(sym, arg.type)) {
+                    return true
+                }
+            }
+        }
+        return false
+    }
+
+    private fun checkType(sym: IrClassSymbol, type: IrType): Boolean {
+        if (type is IrSimpleType) {
+            val decl = type.classifier.owner
+            if (decl.symbol == sym) {
+                return true
+            }
+            if (checkTypeArgs(sym, type.arguments)) {
+                return true
+            }
+        }
+        return false
+    }
+
+    fun possiblyCyclicExtraction(classToCheck: IrClass, args: List<IrTypeArgument>): Boolean {
+        for (c in stack) {
+            if (c.symbol == classToCheck.symbol && checkTypeArgs(c.symbol, args)) {
+                return true
+            }
+        }
+        return false
+    }
+}
+