Subscription reactivity issue for many type links

[gabrielcazacu96]

Issue

Subscription query result does not get updated when a new link is added.

Example

1. Initial data

   Groups:
   [{ _id: 'groupId1'}, {_id: 'groupId2'}]
   Authors:
   [{_id: 'authorId1', groupIds: ['groupdId1']}, {_id: 'authorId2', groupIds: ['groupdId2']}]

2. Query

   const query = createQuery({
   groups: {
       authors: {
           groupIds: 1,
       }
   }
   });

3. If I add groupId1 to the groupIds of authorId2, the query result does not update.
4. Expected subscription query result

   [{ 
   _id: 'groupId1',
   authors: [{_id: 'authorId1', groupIds: ['groupdId1']}, {_id: 'authorId2', groupIds: ['groupdId1', 'groupdId2']}]
   },
   {
   _id: 'groupId2',
   authors: [{_id: 'authorId2', groupIds: ['groupdId2']}]
   }]

5. Actual subscription query result never changes

   [{ 
   _id: 'groupId1',
   authors: [{_id: 'authorId1', groupIds: ['groupdId1']}]
   },
   {
   _id: 'groupId2',
   authors: [{_id: 'authorId2', groupIds: ['groupdId2']}]
   }]

   Additional info

   • This seems to happen only for many type links
   • Issue seems to be related to the meteor-publish-composite package and how the cursor events are triggered.
   • Issue happens only if the linked object is already linked to another parent object in the query. In the example, the author is already linked to another group.

[gabrielcazacu96]

Added demonstration test: https://github.com/cult-of-coders/grapher/pull/482 Only works the first time because after that, the mongodb data is changed.

[gabrielcazacu96]

Added fix attempt to meteor-publish-composite: https://github.com/Meteor-Community-Packages/meteor-publish-composite/pull/177

[gabrielcazacu96]

Thanks to #179 this should no longer be an issue once meteor-publish-composite is updated to version v1.8.8

[StorytellerCZ]

@gabrielcazacu96 per your comment this should be fixed in v1.5