Pseudo-support for multi-labels

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

@@ -46,5 +46,5 @@ class Assignment(
     /** The holder of this assignment */
     @JsonIgnore val holder: AssignmentHolder
 ) : Edge<Node>(value, target as Node) {
-    override var label: String = "ASSIGMENT"
+    override var labels = setOf("ASSIGMENT")
 }

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

@@ -109,7 +109,7 @@ fun <T : Edge<Node>> Node.printGraph(
 private fun Edge<Node>.label(): String {
     val builder = StringBuilder()
     builder.append("\"")
-    builder.append(this.label)
+    builder.append(this.labels)
 
     if (this is Dataflow) {
         var granularity = this.granularity

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

@@ -71,7 +71,7 @@ abstract class Edge<NodeType : Node> : Persistable, Cloneable {
         end = edge.end
     }
 
-    abstract var label: String
+    abstract var labels: Set<String>
 
     /**
      * The index of this node, if it is stored in an

cpg-core/src/main/kotlin/de/fraunhofer/aisec/cpg/graph/edges/ast/AstEdge.kt

@@ -33,7 +33,7 @@ import org.neo4j.ogm.annotation.*
 
 /** This property edge describes a parent/child relationship in the Abstract Syntax Tree (AST). */
 @RelationshipEntity
-open class AstEdge<T : Node>(start: Node, end: T, override var label: String = "AST") :
+open class AstEdge<T : Node>(start: Node, end: T, override var labels: Set<String> = setOf("AST")) :
     Edge<T>(start, end) {
     init {
         end.astParent = start
@@ -42,7 +42,7 @@ open class AstEdge<T : Node>(start: Node, end: T, override var label: String = "
 
 /** Creates an [AstEdges] container starting from this node. */
 fun <NodeType : Node> Node.astEdgesOf(
-    label: String = "AST",
+    label: String? = null,
     onAdd: ((AstEdge<NodeType>) -> Unit)? = null,
     onRemove: ((AstEdge<NodeType>) -> Unit)? = null,
 ): AstEdges<NodeType, AstEdge<NodeType>> {
@@ -54,12 +54,12 @@ fun <NodeType : Node> Node.astEdgesOf(
  * container).
  */
 fun <NodeType : Node> Node.astOptionalEdgeOf(
-    label: String = "AST",
+    label: String? = null,
     onChanged: ((old: AstEdge<NodeType>?, new: AstEdge<NodeType>?) -> Unit)? = null
 ): EdgeSingletonList<NodeType, NodeType?, AstEdge<NodeType>> {
     return EdgeSingletonList(
         thisRef = this,
-        init = { start, end -> AstEdge(start, end, label = label) },
+        init = { start, end -> AstEdge(start, end, labels = setOfNotNull(label, "AST")) },
         outgoing = true,
         onChanged = onChanged,
         of = null
@@ -71,12 +71,12 @@ fun <NodeType : Node> Node.astOptionalEdgeOf(
  */
 fun <NodeType : Node> Node.astEdgeOf(
     of: NodeType,
-    label: String,
+    label: String? = null,
     onChanged: ((old: AstEdge<NodeType>?, new: AstEdge<NodeType>?) -> Unit)? = null,
 ): EdgeSingletonList<NodeType, NodeType, AstEdge<NodeType>> {
     return EdgeSingletonList(
         thisRef = this,
-        init = { start, end -> AstEdge(start, end, label = label) },
+        init = { start, end -> AstEdge(start, end, labels = setOfNotNull(label, "AST")) },
         outgoing = true,
         onChanged = onChanged,
         of = of
@@ -86,12 +86,12 @@ fun <NodeType : Node> Node.astEdgeOf(
 /** This property edge list describes elements that are AST children of a node. */
 open class AstEdges<NodeType : Node, PropertyEdgeType : AstEdge<NodeType>>(
     thisRef: Node,
-    label: String = "AST",
+    label: String? = null,
     onAdd: ((PropertyEdgeType) -> Unit)? = null,
     onRemove: ((PropertyEdgeType) -> Unit)? = null,
     @Suppress("UNCHECKED_CAST")
     init: (start: Node, end: NodeType) -> PropertyEdgeType = { start, end ->
-        AstEdge(start, end, label = label) as PropertyEdgeType
+        AstEdge(start, end, labels = setOfNotNull(label, "AST")) as PropertyEdgeType
     },
 ) :
     EdgeList<NodeType, PropertyEdgeType>(

cpg-core/src/main/kotlin/de/fraunhofer/aisec/cpg/graph/edges/ast/TemplateArgument.kt

@@ -35,7 +35,7 @@ class TemplateArgument<NodeType : Node>(
     end: NodeType,
     label: String,
     var instantiation: TemplateInitialization? = TemplateInitialization.EXPLICIT,
-) : AstEdge<NodeType>(start, end, label)
+) : AstEdge<NodeType>(start, end, setOf(label, "AST"))
 
 /** A container for [TemplateArgument] edges. */
 class TemplateArguments<NodeType : Node>(thisRef: Node, label: String) :

cpg-core/src/main/kotlin/de/fraunhofer/aisec/cpg/graph/edges/flows/ControlDependence.kt

@@ -49,7 +49,7 @@ class ControlDependence(
         dependence = DependenceType.CONTROL
     }
 
-    override var label: String = "CDG"
+    override var labels = setOf("CDG")
 
     override fun equals(other: Any?): Boolean {
         if (this === other) return true

cpg-core/src/main/kotlin/de/fraunhofer/aisec/cpg/graph/edges/flows/Dataflow.kt

@@ -93,7 +93,7 @@ open class Dataflow(
     @JsonIgnore
     var granularity: Granularity = default()
 ) : Edge<Node>(start, end) {
-    override var label: String = "DFG"
+    override var labels = setOf("DFG")
 
     override fun equals(other: Any?): Boolean {
         if (this === other) return true
@@ -134,7 +134,7 @@ class ContextSensitiveDataflow(
     val callingContext: CallingContext
 ) : Dataflow(start, end, granularity) {
 
-    override var label: String = "DFG"
+    override var labels = setOf("DFG")
 
     override fun equals(other: Any?): Boolean {
         if (this === other) return true

cpg-core/src/main/kotlin/de/fraunhofer/aisec/cpg/graph/edges/flows/EvaluationOrder.kt

@@ -69,7 +69,7 @@ class EvaluationOrder(
         return result
     }
 
-    override var label: String = "EOG"
+    override var labels = setOf("EOG")
 }
 
 /**

cpg-core/src/main/kotlin/de/fraunhofer/aisec/cpg/graph/edges/flows/Invoke.kt

@@ -43,7 +43,7 @@ class Invoke(
      */
     var dynamicInvoke: Boolean = false,
 ) : Edge<FunctionDeclaration>(start, end) {
-    override var label: String = "INVOKES"
+    override var labels = setOf("INVOKES")
 
     override fun equals(other: Any?): Boolean {
         if (this === other) return true

cpg-core/src/main/kotlin/de/fraunhofer/aisec/cpg/graph/edges/flows/Usage.kt

@@ -53,7 +53,7 @@ class Usage(
         return result
     }
 
-    override var label: String = "USAGE"
+    override var labels = setOf("USAGE")
 }
 
 /** A container for [Usage] edges. [NodeType] is necessary because of the Neo4J OGM. */

cpg-core/src/main/kotlin/de/fraunhofer/aisec/cpg/graph/statements/expressions/CallExpression.kt

@@ -121,7 +121,7 @@ open class CallExpression :
 
     /** Adds the specified [expression] with an optional [name] to this call. */
     fun addArgument(expression: Expression, name: String? = null) {
-        val edge = AstEdge(this, expression, label = "ARGUMENTS")
+        val edge = AstEdge(this, expression, labels = setOf("ARGUMENTS", "ARGUMENT"))
         edge.name = name
 
         argumentEdges.add(edge)

cpg-neo4j/src/main/kotlin/de/fraunhofer/aisec/cpg/v2/Persistence.kt

@@ -138,12 +138,16 @@ private fun Collection<Edge<*>>.persist() {
 
     this.chunked(edgeChunkSize).map { chunk ->
         createRelationships(
-            chunk.map {
-                mapOf(
-                    "startId" to it.start.id.toString(),
-                    "endId" to it.end.id.toString(),
-                    "type" to it.label
-                ) + it.properties()
+            chunk.flatMap { edge ->
+                // Since Neo4J does not support multiple labels on edges, but we do internally, we
+                // duplicate the edge for each label
+                edge.labels.map { label ->
+                    mapOf(
+                        "startId" to edge.start.id.toString(),
+                        "endId" to edge.end.id.toString(),
+                        "type" to label
+                    ) + edge.properties()
+                }
             }
         )
     }