From 4903bc5149e8175e386bf6858e2168570cd6fe92 Mon Sep 17 00:00:00 2001
From: Tony Garnock-Jones <tonyg@leastfixedpoint.com>
Date: Sun, 3 Dec 2023 22:35:47 +0100
Subject: [PATCH] Allow prettier display of dataflow cyclic dependencies

---
 packages/core/src/runtime/actor.ts    |  4 +++-
 packages/core/src/runtime/dataflow.ts | 14 ++++++--------
 2 files changed, 9 insertions(+), 9 deletions(-)

diff --git a/packages/core/src/runtime/actor.ts b/packages/core/src/runtime/actor.ts
index 91a2a5b..acd6b67 100644
--- a/packages/core/src/runtime/actor.ts
+++ b/packages/core/src/runtime/actor.ts
@@ -131,7 +131,9 @@ export class Actor {
     get dataflowGraph(): DataflowGraph {
         if (this._dataflowGraph === null) {
             this._dataflowGraph =
-                new Graph((b: DataflowBlock) => '' + embeddedId(b), Cell.canonicalizer);
+                new Graph((b: DataflowBlock) => '' + embeddedId(b),
+                          Cell.canonicalizer,
+                          g => Array.from(g.values()));
         }
         return this._dataflowGraph;
     }
diff --git a/packages/core/src/runtime/dataflow.ts b/packages/core/src/runtime/dataflow.ts
index c153dd1..5176bce 100644
--- a/packages/core/src/runtime/dataflow.ts
+++ b/packages/core/src/runtime/dataflow.ts
@@ -15,18 +15,16 @@ export interface ObservingGraph<ObjectId> {
 export class Graph<SubjectId, ObjectId> implements ObservingGraph<ObjectId> {
     readonly edgesForward: FlexMap<ObjectId, FlexSet<SubjectId>>;
     readonly edgesReverse: FlexMap<SubjectId, FlexSet<ObjectId>>;
-    readonly subjectIdCanonicalizer: Canonicalizer<SubjectId>;
-    readonly objectIdCanonicalizer: Canonicalizer<ObjectId>;
     damagedNodes: FlexSet<ObjectId>;
     currentSubjectId: SubjectId | undefined;
 
-    constructor(subjectIdCanonicalizer: Canonicalizer<SubjectId>,
-                objectIdCanonicalizer: Canonicalizer<ObjectId>)
-    {
+    constructor(
+        public readonly subjectIdCanonicalizer: Canonicalizer<SubjectId>,
+        public readonly objectIdCanonicalizer: Canonicalizer<ObjectId>,
+        public formatCycle: (group: FlexSet<ObjectId>) => any = g => g,
+    ) {
         this.edgesForward = new FlexMap(objectIdCanonicalizer);
         this.edgesReverse = new FlexMap(subjectIdCanonicalizer);
-        this.subjectIdCanonicalizer = subjectIdCanonicalizer;
-        this.objectIdCanonicalizer = objectIdCanonicalizer;
         this.damagedNodes = new FlexSet(objectIdCanonicalizer);
     }
 
@@ -75,7 +73,7 @@ export class Graph<SubjectId, ObjectId> implements ObservingGraph<ObjectId> {
 
             const alreadyDamaged = workSet.intersect(repairedThisRound);
             if (alreadyDamaged.size > 0) {
-                console.warn('Cyclic dependencies involving', alreadyDamaged);
+                console.warn('Cyclic dependencies involving', this.formatCycle(alreadyDamaged));
             }
 
             workSet = workSet.subtract(repairedThisRound);