sheet: keep record of proxy names, display cell triggering proxy cycle

src/proxy.ts

@@ -34,7 +34,7 @@ export class SheetProxy {
     this.working = new Working(sh.working);
     this.errors = new CellErrors(sh.errors);
     if (name) this._name = name;
-    this._id = sh.addProxy();
+    this._id = sh.addProxy(name);
   }
 
   // a Sheet has id 0, proxies > 0
@@ -213,7 +213,7 @@ export class SheetProxy {
     // @ts-expect-error conflict with overloaded definitions
     const cell = this._sheet.map(dependencies, computeFn, name, this, noFail);
     this._list.push(cell);
-    this._sheet.addProxyDependencies(this._id, dependencies);
+    this._sheet.addProxyDependencies(this._id, dependencies, cell.id);
     return cell as MapCell<V, NF>;
   }
 
@@ -239,7 +239,7 @@ export class SheetProxy {
       noFail
     );
     this._list.push(cell);
-    this._sheet.addProxyDependencies(this._id, dependencies);
+    this._sheet.addProxyDependencies(this._id, dependencies, cell.id);
     return cell;
   }
 

src/sheet.ts

@@ -118,6 +118,7 @@ export class Sheet {
   private _gc: Set<number>;
 
   private _proxies: Graph<number>;
+  private _proxyNames: Record<number, string>;
 
   /**
    * @param equality function comparing a new value with previous value for updates
@@ -141,29 +142,40 @@ export class Sheet {
     this._queue = [];
     this._proxies = new Graph();
     this._proxies.addNode(0);
+    this._proxyNames = {};
   }
 
   // a Sheet has id 0, proxies > 0
   get id() {
     return 0;
   }
 
-  addProxy() {
+  addProxy(name?: string) {
     // keeping 0 as original Sheet
     this[proxies]++;
     const id = this[proxies];
     this._proxies.addNode(id);
+    this._proxyNames[id] = name;
     return id;
   }
 
   addProxyEdge(from: number, to: number) {
     this._proxies.addEdge(from, to);
   }
-  addProxyDependencies(id: number, deps: AnyCellArray<unknown[]>) {
+  addProxyDependencies(
+    id: number,
+    deps: AnyCellArray<unknown[]>,
+    cell: number
+  ) {
     for (const dep of deps)
       if (dep._proxy !== id) this.addProxyEdge(dep._proxy, id);
     if (this._proxies.topologicalSort() === null)
-      this.debug(undefined, "proxy cycle", { proxy: id, deps });
+      this.debug(undefined, "proxy cycle", {
+        proxy: id,
+        cell,
+        name: this._proxyNames[id],
+        deps
+      });
     this._queue = [];
   }