fix(json-crdt): 🐛 do not detach builder clock on .reset()

Author: streamich

src/json-crdt/model/Model.ts

@@ -308,7 +308,8 @@ export class Model<N extends JsonNode = JsonNode<any>> implements Printable {
 
   /**
    * Applies a single patch to the document. All mutations to the model must go
-   * through this method.
+   * through this method. (With the only exception of local changes through API,
+   * which have an alternative path.)
    */
   public applyPatch(patch: Patch) {
     this.onbeforepatch?.(patch);
@@ -492,7 +493,11 @@ export class Model<N extends JsonNode = JsonNode<any>> implements Printable {
     decoder.decode(blob, <any>this);
     this.clock = to.clock.clone();
     this.ext = to.ext.clone();
-    this._api?.flush();
+    const api = this._api;
+    if (api) {
+      api.flush();
+      api.builder.clock = this.clock;
+    }
     index.forEach(({v: node}) => {
       const api = node.api as NodeApi | undefined;
       if (!api) return;

src/json-crdt/model/__tests__/Model.cloning.spec.ts

@@ -252,4 +252,19 @@ describe('reset()', () => {
     doc1.reset(doc2);
     expect(str.view()).toBe('hello');
   });
+
+  test('uses the same clock in Model and NodeBuilder', async () => {
+    const doc1 = Model.create().setSchema(
+      schema.obj({
+        text: schema.str('hell'),
+      }),
+    );
+    const doc2 = doc1.fork();
+    doc2.s.text.toApi().ins(4, 'o');
+    expect(doc1.clock).toBe(doc1.api.builder.clock);
+    expect(doc2.clock).toBe(doc2.api.builder.clock);
+    doc1.reset(doc2);
+    expect(doc1.clock).toBe(doc1.api.builder.clock);
+    expect(doc2.clock).toBe(doc2.api.builder.clock);
+  });
 });