Replace TODO() with ProblemDeclaration nodes

cpg-core/src/main/kotlin/de/fraunhofer/aisec/cpg/graph/DeclarationBuilder.kt

@@ -403,6 +403,27 @@ fun MetadataProvider.newProblemDeclaration(
     return node
 }
 
+/**
+ * Creates a new [Problem]. The [MetadataProvider] receiver will be used to fill different meta-data
+ * using [Node.applyMetadata]. Calling this extension function outside of Kotlin requires an
+ * appropriate [MetadataProvider], such as a [LanguageFrontend] as an additional prepended argument.
+ */
+@JvmOverloads
+fun MetadataProvider.newProblem(
+    problem: String = "",
+    problemType: ProblemNode.ProblemType = ProblemNode.ProblemType.PARSING,
+    rawNode: Any? = null
+): Problem {
+    val node = Problem()
+    node.applyMetadata(this, EMPTY_NAME, rawNode, true)
+
+    node.problem = problem
+    node.problemType = problemType
+
+    log(node)
+    return node
+}
+
 /**
  * Creates a new [IncludeDeclaration]. The [MetadataProvider] receiver will be used to fill
  * different meta-data using [Node.applyMetadata]. Calling this extension function outside of Kotlin

cpg-core/src/main/kotlin/de/fraunhofer/aisec/cpg/graph/Node.kt

@@ -257,6 +257,12 @@ abstract class Node :
     @Relationship("ANNOTATIONS") var annotationEdges = astEdgesOf<Annotation>()
     var annotations by unwrapping(Node::annotationEdges)
 
+    /**
+     * Additional problem nodes. These nodes represent problems which occurred during processing of
+     * a node (i.e. only partially processed).
+     */
+    val additionalProblems: MutableSet<ProblemNode> = mutableSetOf()
+
     /**
      * If a node should be removed from the graph, just removing it from the AST is not enough (see
      * issue #60). It will most probably be referenced somewhere via DFG or EOG edges. Thus, if it

cpg-core/src/main/kotlin/de/fraunhofer/aisec/cpg/graph/Problem.kt

@@ -0,0 +1,32 @@
+/*
+ * Copyright (c) 2024, Fraunhofer AISEC. All rights reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ *                    $$$$$$\  $$$$$$$\   $$$$$$\
+ *                   $$  __$$\ $$  __$$\ $$  __$$\
+ *                   $$ /  \__|$$ |  $$ |$$ /  \__|
+ *                   $$ |      $$$$$$$  |$$ |$$$$\
+ *                   $$ |      $$  ____/ $$ |\_$$ |
+ *                   $$ |  $$\ $$ |      $$ |  $$ |
+ *                   \$$$$$   |$$ |      \$$$$$   |
+ *                    \______/ \__|       \______/
+ *
+ */
+package de.fraunhofer.aisec.cpg.graph
+
+/** A problem node documenting that something failed. */
+data class Problem(
+    override var problem: String = "",
+    override var problemType: ProblemNode.ProblemType = ProblemNode.ProblemType.TRANSLATION
+) : ProblemNode, MetadataProvider, Node()

cpg-language-python/src/main/kotlin/de/fraunhofer/aisec/cpg/frontends/python/StatementHandler.kt

@@ -113,7 +113,7 @@ class StatementHandler(frontend: PythonLanguageFrontend) :
             // Wildcards luckily do not have aliases
             val decl =
                 if (imp.name == "*") {
-                    // In the wildcard case, our "import" is the module name and we set "wildcard"
+                    // In the wildcard case, our "import" is the module name, and we set "wildcard"
                     // to true
                     newImportDeclaration(module, true, rawNode = imp)
                 } else {
@@ -139,7 +139,13 @@ class StatementHandler(frontend: PythonLanguageFrontend) :
         val ret = newWhileStatement(rawNode = node)
         ret.condition = frontend.expressionHandler.handle(node.test)
         ret.statement = makeBlock(node.body).codeAndLocationFromChildren(node)
-        node.orelse.firstOrNull()?.let { TODO("Not supported") }
+        if (node.orelse.isNotEmpty()) {
+            ret.additionalProblems +=
+                newProblem(
+                    problem = "Cannot handle \"orelse\" in while loops.",
+                    rawNode = node.orelse
+                )
+        }
         return ret
     }
 
@@ -148,7 +154,13 @@ class StatementHandler(frontend: PythonLanguageFrontend) :
         ret.iterable = frontend.expressionHandler.handle(node.iter)
         ret.variable = frontend.expressionHandler.handle(node.target)
         ret.statement = makeBlock(node.body).codeAndLocationFromChildren(node)
-        node.orelse.firstOrNull()?.let { TODO("Not supported") }
+        if (node.orelse.isNotEmpty()) {
+            ret.additionalProblems +=
+                newProblem(
+                    problem = "Cannot handle \"orelse\" in for loops.",
+                    rawNode = node.orelse
+                )
+        }
         return ret
     }
 
@@ -157,7 +169,13 @@ class StatementHandler(frontend: PythonLanguageFrontend) :
         ret.iterable = frontend.expressionHandler.handle(node.iter)
         ret.variable = frontend.expressionHandler.handle(node.target)
         ret.statement = makeBlock(node.body).codeAndLocationFromChildren(node)
-        node.orelse.firstOrNull()?.let { TODO("Not supported") }
+        if (node.orelse.isNotEmpty()) {
+            ret.additionalProblems +=
+                newProblem(
+                    problem = "Cannot handle \"orelse\" in async for loops.",
+                    rawNode = node.orelse
+                )
+        }
         return ret
     }
 
@@ -241,9 +259,8 @@ class StatementHandler(frontend: PythonLanguageFrontend) :
         frontend.scopeManager.enterScope(cls)
 
         stmt.keywords.forEach {
-            frontend.currentTU?.addDeclaration(
-                newProblemDeclaration("could not parse keyword $it in class")
-            )
+            cls.additionalProblems +=
+                newProblem(problem = "could not parse keyword $it in class", rawNode = it)
         }
 
         for (s in stmt.body) {
@@ -391,20 +408,19 @@ class StatementHandler(frontend: PythonLanguageFrontend) :
     ) {
         // We can merge posonlyargs and args because both are positional arguments. We do not
         // enforce that posonlyargs can ONLY be used in a positional style, whereas args can be used
-        // both in positional as well as keyword style.
+        // both in positional and keyword style.
         var positionalArguments = args.posonlyargs + args.args
         // Handle arguments
         if (recordDeclaration != null) {
             // first argument is the `receiver`
             val recvPythonNode = positionalArguments.firstOrNull()
             if (recvPythonNode == null) {
-                val problem =
-                    newProblemDeclaration(
+                result.additionalProblems +=
+                    newProblem(
                         "Expected a receiver",
                         problemType = ProblemNode.ProblemType.TRANSLATION,
                         rawNode = args
                     )
-                frontend.scopeManager.addDeclaration(problem)
             } else {
                 val tpe = recordDeclaration.toType()
                 val recvNode =
@@ -418,15 +434,24 @@ class StatementHandler(frontend: PythonLanguageFrontend) :
                 when (result) {
                     is ConstructorDeclaration -> result.receiver = recvNode
                     is MethodDeclaration -> result.receiver = recvNode
-                    else -> TODO()
+                    else ->
+                        result.additionalProblems +=
+                            newProblem(
+                                problem =
+                                    "Expected a constructor or method declaration. Got something else.",
+                                rawNode = result
+                            )
                 }
             }
         }
 
         if (recordDeclaration != null) {
-            // first argument is the receiver
-            for (arg in positionalArguments.subList(1, positionalArguments.size)) {
-                handleArgument(arg, arg in args.posonlyargs)
+            if (
+                positionalArguments.size > 1 // more arguments than only a receiver
+            ) { // first argument is the receiver
+                for (arg in positionalArguments.subList(1, positionalArguments.size)) {
+                    handleArgument(arg, arg in args.posonlyargs)
+                }
             }
         } else {
             for (arg in positionalArguments) {
@@ -437,43 +462,39 @@ class StatementHandler(frontend: PythonLanguageFrontend) :
         args.vararg?.let { handleArgument(it, isPosOnly = false, isVariadic = true) }
 
         if (args.kwonlyargs.isNotEmpty()) {
-            val problem =
+            result.additionalProblems +=
                 newProblemDeclaration(
                     "`kwonlyargs` are not yet supported",
                     problemType = ProblemNode.ProblemType.TRANSLATION,
                     rawNode = args
                 )
-            frontend.scopeManager.addDeclaration(problem)
         }
 
         if (args.kw_defaults.isNotEmpty()) {
-            val problem =
+            result.additionalProblems +=
                 newProblemDeclaration(
                     "`kw_defaults` are not yet supported",
                     problemType = ProblemNode.ProblemType.TRANSLATION,
                     rawNode = args
                 )
-            frontend.scopeManager.addDeclaration(problem)
         }
 
         args.kwarg?.let {
-            val problem =
+            result.additionalProblems +=
                 newProblemDeclaration(
                     "`kwarg` is not yet supported",
                     problemType = ProblemNode.ProblemType.TRANSLATION,
                     rawNode = it
                 )
-            frontend.scopeManager.addDeclaration(problem)
         }
 
         if (args.defaults.isNotEmpty()) {
-            val problem =
+            result.additionalProblems +=
                 newProblemDeclaration(
                     "`defaults` are not yet supported",
                     problemType = ProblemNode.ProblemType.TRANSLATION,
                     rawNode = args
                 )
-            frontend.scopeManager.addDeclaration(problem)
         }
     }