fix: Race condition for pouchdb hanging indefinitely when multiple instances are used

packages/node_modules/pouchdb-adapter-leveldb-core/src/index.js

@@ -4,6 +4,7 @@ import { obj as through } from 'through2';
 import getArguments from 'argsarray';
 import Deque from 'double-ended-queue';
 import bufferFrom from 'buffer-from'; // ponyfill for Node <6
+import PouchDB from 'pouchdb-core';
 import {
   clone,
   changesHandler as Changes,
@@ -1176,7 +1177,8 @@ function LevelPouch(opts, callback) {
 
         var adapterName = functionName(leveldown);
         var adapterStore = dbStores.get(adapterName);
-        var keys = [...adapterStore.keys()].filter(k => k.includes("-mrview-"));
+        var viewNamePrefix = PouchDB.prefix + name + "-mrview-";
+        var keys = [...adapterStore.keys()].filter(k => k.includes(viewNamePrefix));
         keys.forEach(key => {
           var eventEmitter = adapterStore.get(key);
           eventEmitter.removeAllListeners();

tests/unit/test.memory-adapter.js

@@ -0,0 +1,79 @@
+var PouchDB = require('../../packages/node_modules/pouchdb-for-coverage');
+var memoryAdapter = require('../../packages/node_modules/pouchdb-adapter-memory');
+PouchDB.plugin(memoryAdapter);
+
+describe('test.memory-adapter.js', () => {
+  it('Race condition initially discovered with PouchDB in-memory-adapter 7.3.0', async () => {
+    const func1 = async () => {
+      const pouch1 = new PouchDB('test-db', {
+        adapter: 'memory'
+      });
+      const docId = 'func1doc1';
+
+      // insert
+      await pouch1.bulkDocs({
+        docs: [{
+          _id: docId,
+          value: 1,
+          _rev: '1-51b2fae5721cc4d3cf7392f19e6cc118'
+        }]
+      }, {
+        new_edits: false
+      });
+
+      // update
+      let getDocs = await pouch1.bulkGet({
+        docs: [{id: docId}],
+        revs: true,
+        latest: true
+      });
+      const useRevs = (getDocs).
+      results[0].docs[0].ok._revisions;
+      useRevs.start = useRevs.start + 1;
+      useRevs.ids.unshift('a723631364fbfa906c5ffa8203ac9725');
+
+      await pouch1.bulkDocs({
+        docs: [{
+          _id: docId,
+          value: 2,
+          _rev: '2-a723631364fbfa906c5ffa8203ac9725',
+          _revisions: useRevs
+        }]
+      }, {
+        new_edits: false
+      });
+
+      // delete
+      getDocs = await pouch1.bulkGet({
+        docs: [{id: docId}],
+        revs: true,
+        latest: true
+      });
+
+      // same via .get
+      await pouch1.get(docId);
+      // if this is switched to pouch1.destroy(); ... this test will pass.
+      pouch1.close();
+    };
+
+    const func2 = async () => {
+      const pouch2 = new PouchDB(
+        'test-db-2', {
+          adapter: 'memory',
+        });
+
+      await pouch2.createIndex({
+        index: {
+          fields: ['foo']
+        }
+      });
+      pouch2.destroy();
+    };
+
+    // func1 succeeds when run alone.
+    // func2 succeeds when run alone.
+    // As of PouchDB 7.3.0, when running these functions in parallel, there is a race condition where func2 gets
+    // impacted by func1. The result: func2 will hang and the test will timeout.
+    await Promise.all([func1(), func2()]);
+  });
+});