removal of potentially harmful parameter.

I managed to build an inconsistent graph as the edge.directed information was overwritten by addEdge(_, directed:). Now, the directed parameter is no longer needed. Instead, the information is taken from the Edge parameter.

Author: KneupnerTrackunit

Sources/SwiftGraph/Graph.swift

@@ -26,7 +26,7 @@ public protocol Graph: CustomStringConvertible, Collection, Codable {
     var edges: [[E]] { get set }
 
     init(vertices: [V])
-    func addEdge(_ e: E, directed: Bool)
+    func addEdge(_ e: E)
 }
 
 extension Graph {
@@ -137,12 +137,9 @@ extension Graph {
     /// Add an edge to the graph.
     ///
     /// - parameter e: The edge to add.
-    /// - parameter directed: If false, undirected edges are created.
-    ///                       If true, a reversed edge is also created.
-    ///                       Default is false.
-    public mutating func addEdge(_ e: E, directed: Bool = false) {
+    public mutating func addEdge(_ e: E) {
         edges[e.u].append(e)
-        if !directed && e.u != e.v {
+        if !e.directed && e.u != e.v {
             edges[e.v].append(e.reversed())
         }
     }

Sources/SwiftGraph/Reversed.swift

@@ -25,7 +25,7 @@ extension Graph {
     public func reversed() -> Self {
         let g = Self(vertices: self.vertices)
         for e in self.edgeList() {
-            g.addEdge(e.reversed(), directed: e.directed)
+            g.addEdge(e.reversed())
         }
         return g
     }

Sources/SwiftGraph/Union.swift

@@ -43,7 +43,7 @@ public extension UniqueElementsGraph where E == UnweightedEdge {
         // When vertices are removed from Graph, edges might mutate,
         // so we need to add new copies of them for the result graph.
         for edge in firstGraph.edges.joined() {
-            union.addEdge(edge, directed: true)
+            union.addEdge(edge)
         }
 
         for g in others {

Sources/SwiftGraph/UniqueElementsGraph.swift

@@ -50,14 +50,11 @@ open class UniqueElementsGraph<V: Equatable & Codable, E: Edge & Equatable>: Gra
     /// Add an edge to the graph. Only allow the edge to be added once
     ///
     /// - parameter e: The edge to add.
-    /// - parameter directed: If false, undirected edges are created.
-    ///                       If true, a reversed edge is also created.
-    ///                       Default is false.
-    public func addEdge(_ e: E, directed: Bool = false) {
+    public func addEdge(_ e: E) {
         if !self.edgeExists(e) {
             edges[e.u].append(e)
         }
-        if !directed {
+        if !e.directed {
             let reversedEdge = e.reversed()
             if !edgeExists(reversedEdge) {
                 edges[e.v].append(reversedEdge)

Sources/SwiftGraph/UnweightedGraph.swift

@@ -33,12 +33,9 @@ open class UnweightedGraph<V: Equatable & Codable>: Graph {
     /// Add an edge to the graph.
     ///
     /// - parameter e: The edge to add.
-    /// - parameter directed: If false, undirected edges are created.
-    ///                       If true, a reversed edge is also created.
-    ///                       Default is false.
-    public func addEdge(_ e: UnweightedEdge, directed: Bool) {
+    public func addEdge(_ e: UnweightedEdge) {
         edges[e.u].append(e)
-        if !directed && e.u != e.v {
+        if !e.directed && e.u != e.v {
             edges[e.v].append(e.reversed())
         }
     }
@@ -112,7 +109,7 @@ extension Graph where E == UnweightedEdge {
     /// - parameter to: The ending vertex's index.
     /// - parameter directed: Is the edge directed? (default `false`)
     public func addEdge(fromIndex: Int, toIndex: Int, directed: Bool = false) {
-        addEdge(UnweightedEdge(u: fromIndex, v: toIndex, directed: directed), directed: directed)
+        addEdge(UnweightedEdge(u: fromIndex, v: toIndex, directed: directed))
     }
 
     /// This is a convenience method that adds an unweighted, undirected edge between the first occurence of two vertices. It takes O(n) time.
@@ -122,7 +119,7 @@ extension Graph where E == UnweightedEdge {
     /// - parameter directed: Is the edge directed? (default `false`)
     public func addEdge(from: V, to: V, directed: Bool = false) {
         if let u = indexOfVertex(from), let v = indexOfVertex(to) {
-            addEdge(UnweightedEdge(u: u, v: v, directed: directed), directed: directed)
+            addEdge(UnweightedEdge(u: u, v: v, directed: directed))
         }
     }
 

Sources/SwiftGraph/WeightedGraph.swift

@@ -34,12 +34,9 @@ open class WeightedGraph<V: Equatable & Codable, W: Equatable & Codable>: Graph
     /// Add an edge to the graph.
     ///
     /// - parameter e: The edge to add.
-    /// - parameter directed: If false, undirected edges are created.
-    ///                       If true, a reversed edge is also created.
-    ///                       Default is false.
-    public func addEdge(_ e: WeightedEdge<W>, directed: Bool) {
+    public func addEdge(_ e: WeightedEdge<W>) {
         edges[e.u].append(e)
-        if !directed && e.u != e.v {
+        if !e.directed && e.u != e.v {
             edges[e.v].append(e.reversed())
         }
     }
@@ -77,7 +74,7 @@ extension Graph where E: WeightedEdgeProtocol {
     /// - parameter directed: Is the edge directed? (default false)
     /// - parameter weight: the Weight of the edge to add.
     public func addEdge(fromIndex: Int, toIndex: Int, weight: W, directed: Bool = false) {
-        addEdge(E(u: fromIndex, v: toIndex, directed: directed, weight: weight), directed: directed)
+        addEdge(E(u: fromIndex, v: toIndex, directed: directed, weight: weight))
     }
 
     /// This is a convenience method that adds a weighted edge between the first occurence of two vertices. It takes O(n) time.

Tests/SwiftGraphTests/SwiftGraphTests.swift

@@ -81,7 +81,7 @@ class SwiftGraphTests: XCTestCase {
         let arezzoIndex = g.addVertex("Arezzo")
         g.addEdge(from: "Atlanta", to: "New York", directed: true)
         let nyAtlantaEdge = UnweightedEdge(u: nyIndex, v: atlantaIndex, directed: true)
-        g.addEdge(nyAtlantaEdge, directed: true)
+        g.addEdge(nyAtlantaEdge)
         g.addEdge(from: "Miami", to: "Atlanta", directed: true)
         g.addEdge(from: "New York", to: "Miami", directed: false)
         g.addEdge(from: "Atlanta", to: "Miami", directed: true)