fix(wallet): preserve pouchdb collection documents when bulkDocs fails

PouchDbCollectionStore.setAll used to
1. delete all documents
2. insert the new documents

This approach has a problem that when step 2. fails, all documents from
db are gone and not re-created. For some collections such as
transactions or utxo this is not a problem, because it can recover, but
for it is a big problem for WalletRepository, because there is no way
to recover the wallets if they are lost.

This fix updates setAll to perform the following steps:
1. delete *only* the documents that are intended to be deleted
2. upsert all new documents

packages/wallet/package.json

@@ -81,7 +81,8 @@
     "pouchdb": "^7.3.0",
     "rxjs": "^7.4.0",
     "ts-custom-error": "^3.2.0",
-    "ts-log": "^2.2.3"
+    "ts-log": "^2.2.3",
+    "uuid": "^8.3.2"
   },
   "files": [
     "dist/*",

packages/wallet/src/persistence/pouchDbStores/PouchDbCollectionStore.ts

@@ -4,6 +4,7 @@ import { Logger } from 'ts-log';
 import { PouchDbStore } from './PouchDbStore';
 import { observeAll } from '../util';
 import { sanitizePouchDbDoc } from './util';
+import { v4 } from 'uuid';
 
 export type ComputePouchDbDocId<T> = (doc: T) => string;
 
@@ -14,7 +15,7 @@ export interface PouchDbCollectionStoreProps<T> {
 
 /** PouchDB database that implements CollectionStore. Supports sorting by custom document _id */
 export class PouchDbCollectionStore<T extends {}> extends PouchDbStore<T> implements CollectionStore<T> {
-  readonly #computeDocId: ComputePouchDbDocId<T> | undefined;
+  readonly #computeDocId: ComputePouchDbDocId<T>;
   readonly #updates$ = new Subject<T[]>();
 
   observeAll: CollectionStore<T>['observeAll'];
@@ -29,7 +30,7 @@ export class PouchDbCollectionStore<T extends {}> extends PouchDbStore<T> implem
     // Using a db per collection
     super(dbName, logger);
     this.observeAll = observeAll(this, this.#updates$);
-    this.#computeDocId = computeDocId;
+    this.#computeDocId = computeDocId ?? (() => v4());
   }
 
   getAll(): Observable<T[]> {
@@ -50,13 +51,34 @@ export class PouchDbCollectionStore<T extends {}> extends PouchDbStore<T> implem
     return from(
       (this.idle = this.idle.then(async (): Promise<void> => {
         try {
-          await this.clearDB();
+          const newDocsWithId = docs.map((doc) => ({
+            ...this.toPouchDbDoc(doc),
+            _id: this.#computeDocId(doc)
+          }));
+          const existingDocs = await this.fetchAllDocs();
+          const newDocsWithRev = newDocsWithId.map((newDoc): T & { _id: string; _rev?: string } => {
+            const existingDoc = existingDocs.find((doc) => doc.id === newDoc._id);
+            if (!existingDoc) return newDoc;
+            return {
+              ...newDoc,
+              _rev: existingDoc.value.rev
+            };
+          });
+          const docsToDelete = existingDocs.filter(
+            (existingDoc) => !newDocsWithId.some((newDoc) => newDoc._id === existingDoc.id)
+          );
           await this.db.bulkDocs(
-            docs.map((doc) => ({
-              ...this.toPouchDbDoc(doc),
-              _id: this.#computeDocId?.(doc)
-            }))
+            docsToDelete.map(
+              ({ id, value: { rev } }) =>
+                ({
+                  _deleted: true,
+                  _id: id,
+                  _rev: rev
+                } as unknown as T)
+            )
           );
+          await this.db.bulkDocs(newDocsWithRev);
+
           this.#updates$.next(docs);
         } catch (error) {
           this.logger.error(`PouchDbCollectionStore(${this.dbName}): failed to setAll`, docs, error);

packages/wallet/src/persistence/pouchDbStores/PouchDbStore.ts

@@ -9,7 +9,7 @@ export abstract class PouchDbStore<T extends {}> {
   destroyed = false;
   protected idle: Promise<void> = Promise.resolve();
   protected readonly logger: Logger;
-  protected readonly db: PouchDB.Database<T>;
+  public readonly db: PouchDB.Database<T>;
 
   constructor(public dbName: string, logger: Logger) {
     this.logger = logger;

packages/wallet/src/persistence/pouchDbStores/pouchDbWalletStores.ts

@@ -85,7 +85,11 @@ export const createPouchDbWalletStores = (
     // However it is extremely unlikely that it would have inline datums,
     // and renaming this store is not an option as it's being used
     // for storing collateral settings
-    unspendableUtxo: new PouchDbUtxoStore({ dbName: `${baseDbName}UnspendableUtxo` }, logger),
+    unspendableUtxo: new PouchDbUtxoStore(
+      // random doc id; setAll will always delete and re-insert all docs
+      { dbName: `${baseDbName}UnspendableUtxo` },
+      logger
+    ),
     utxo: new PouchDbUtxoStore({ dbName: `${baseDbName}Utxo_v2` }, logger),
     volatileTransactions: new PouchDbVolatileTransactionsStore(docsDbName, 'volatileTransactions_v3', logger)
   };

packages/wallet/test/persistence/pouchDbStores.test.ts

@@ -82,6 +82,20 @@ describe('pouchDbStores', () => {
       expect(await firstValueFrom(store1.getAll())).toEqual([doc2]);
     });
 
+    it('setAll preserves existing documents if bulkDocs fails', async () => {
+      await firstValueFrom(store1.setAll([doc1]));
+      const originalBulkDocs = store1.db.bulkDocs.bind(store1.db);
+      // 1st call used to clearAll, 2nd call was used to insert new docs.
+      // after the fix, 1st call upserts the documents and 2nd call deletes deleted documents
+      store1.db.bulkDocs = jest.fn().mockImplementationOnce(originalBulkDocs).mockRejectedValueOnce(new Error('fail'));
+
+      // attempting to insert doc2
+      await firstValueFrom(store1.setAll([doc1, doc2]));
+
+      const docs = await firstValueFrom(store1.getAll());
+      expect(docs.length).toBeGreaterThan(0);
+    });
+
     it('simultaneous setAll() calls are resolved in series - last value is always persisted', async () => {
       await firstValueFrom(
         combineLatest([store1.setAll([doc1]), timer(1).pipe(mergeMap(() => store1.setAll([doc2])))])

yarn.lock

@@ -4085,6 +4085,7 @@ __metadata:
     ts-log: ^2.2.3
     tsc-alias: ^1.8.10
     typescript: ^4.7.4
+    uuid: ^8.3.2
     wait-on: ^6.0.1
     webextension-polyfill: ^0.9.0
   languageName: unknown