inMemory collections don't sync up removals

[rafamel]

Case

Bug; inMemory collections don't sync up the removal of documents.

Issue

When a doc is removed on an inMemory, it is still present in its original collection, and also vice versa.

Info

• Environment: Browser
• Adapter: idb, memory
• RxDB: 7.7.1

Code

const RxDB = require('rxdb');
RxDB.plugin(require('pouchdb-adapter-idb'));
RxDB.plugin(require('pouchdb-adapter-memory'));

async function test() {
  const db = await RxDB.create({
    name: 'testdb',
    adapter: 'idb',
    multiInstance: false
  });

  const schema = {
    version: 0,
    type: 'object',
    primaryPath: '_id',
    properties: {
      name: {
        type: 'string'
      }
    }
  };

  const collection = await db.collection({
    name: 'person',
    schema: schema,
    statics: {
      one() {
        return this.findOne();
      }
    }
  });

  // Insertion
  console.log('-'.repeat(20));
  const inMemCollection = await db.collections.person.inMemory();
  collection.insert({ name: 'hi' });
  // Wait
  await new Promise((resolve) => setTimeout(resolve, 1000));
  const inserted = await inMemCollection.findOne().exec();
  console.log(
    'Name in sync with inMemory?',
    inserted && inserted.name === 'hi'
  );

  // Removal from collection
  console.log('-'.repeat(20));
  console.log('Removing from collection');
  await collection
    .findOne()
    .exec()
    .then((x) => x.remove());
  // Wait
  await new Promise((resolve) => setTimeout(resolve, 2000));
  console.log(
    'Was removed from collection?',
    (await collection.findOne().exec()) === null
  );
  console.log(
    'Was removed from inMemory collection?',
    (await inMemCollection.findOne().exec()) === null
  );
  console.log('-'.repeat(20));
}
test();

[rafamel]

This might be related to #761

[pubkey]

Ok this was a hard one :)

First problem was that as described in #761 .remove() did delete all data of the document. I always thought remove would do the same as only setting _deleted: true which was wrong, I changed it and we now use pouch.put() and only set the _deleted-flag

Also there was a bug in the query-change-detection which is fixed now.

Because pouch.bulkDocs does not work for deleting documents silently, I added a workaround which could be removed in the future when the added pouch-db-integration-test fails.

[rafamel]

Amazing work, Daniel!

[hubgit]

@pubkey If a document is deleted remotely and syncs to the local database with the data deleted (as with the old behaviour of .remove()), will the query change detector still handle it correctly?

In other words, if a deleted document used to match the query and now doesn't match the query (because it doesn't have any of the matching properties), will the query subscriber still be called?