Show label for visited items (#43)

Author: brentleyjones

Sources/CustomDump/Diff.swift

@@ -304,13 +304,13 @@ public func diff<T>(_ lhs: T, _ rhs: T, format: DiffFormat = .default) -> String
       let subjectType = typeName(lhsMirror.subjectType)
       if visitedItems.contains(lhsItem) || visitedItems.contains(rhsItem) {
         print(
-          "\(subjectType)(↩︎)"
+          "\(lhsName.map { "\($0): " } ?? "")\(subjectType)(↩︎)"
             .indenting(by: indent)
             .indenting(with: format.first + " "),
           to: &out
         )
         print(
-          "\(subjectType)(↩︎)"
+          "\(rhsName.map { "\($0): " } ?? "")\(subjectType)(↩︎)"
             .indenting(by: indent)
             .indenting(with: format.second + " "),
           terminator: "",

Tests/CustomDumpTests/DiffTests.swift

@@ -74,6 +74,23 @@ final class DiffTests: XCTestCase {
       + NSObject()
       """
     )
+
+    XCTAssertNoDifference(
+      diff(
+        RepeatedObject(id: "a"),
+        RepeatedObject(id: "b")
+      ),
+      """
+        RepeatedObject(
+          child: RepeatedObject.Child(
+      -     grandchild: RepeatedObject.Grandchild(id: "a")
+      +     grandchild: RepeatedObject.Grandchild(id: "b")
+          ),
+      -   grandchild: RepeatedObject.Grandchild(↩︎)
+      +   grandchild: RepeatedObject.Grandchild(↩︎)
+        )
+      """
+    )
   }
 
   func testClassObjectIdentity() {

Tests/CustomDumpTests/Mocks.swift

@@ -3,6 +3,28 @@ import Foundation
 
 class RecursiveFoo { var foo: RecursiveFoo? }
 
+class RepeatedObject {
+    class Child {
+        let grandchild: Grandchild
+        init(id: String) {
+            grandchild = Grandchild(id: id)
+        }
+    }
+    class Grandchild {
+        let id: String
+        init(id: String) {
+            self.id = id
+        }
+    }
+
+    let child: Child
+    let grandchild: Grandchild
+    init(id: String) {
+        child = Child(id: id)
+        grandchild = child.grandchild
+    }
+}
+
 class UserClass {
   let id: Int, name: String
   init(id: Int, name: String) {