Dot notation with doesNotMatchKeyInQuery can throw exceptions when base object doesn't exist

[JacobJT]

Issue Description

When using dot notation on a doesNotMatchKeyInQuery query constraint, the query will error if a result from the original query does not have an object for the base queryKey that uses dot notation. The workaround is to add a exists constraint to the query, though it seems that should be implicit if an error is going to be thrown otherwise.

Steps to reproduce

Create ClassA and ClassB.
Add a pointer field to ClassB on ClassA called classB.
Create one instance of ClassB and two instances of ClassA
On one instance of ClassA, attach the pointer to the instance of ClassB
Call the following cloud code function:

Parse.Cloud.define('queryErrorTest', function(request, response) {
    var queryA = new Parse.Query('ClassA');
    var queryB = new Parse.Query('ClassB');
    queryB.doesNotMatchKeyInQuery('objectId', 'classB.objectId', queryA);
    queryB.count().then(
        results => { response.success(`Found ${count} objects`); },
        error => { response.error('Query Failed'); }
    );
});

Expected Results

Print Found 1 objects

Actual Outcome

An error saying Cannot read property 'objectId' of undefined

Adding the line queryA.exists('classB'); solves the issue, and I get the expected outcome. The error would not occur if there were no instances of ClassA that did not have their classB pointer, so keep that in mind if a test case is written. If dot notation is used on the queryKey parameter of doesNotMatchKeyInQuery, the exists call should be implicit. Without knowing the code that is actually being run, it seems like another fix would be to add an undefined check before trying to access the nested field, but the implicit exists call seems to me to be a more efficient solution.

I have not tested this on the other related methods, like matchesKeyInQuery, though I imagine results would be similar. I also only tested this on the queryKey parameter.

Environment Setup

• Server

  • parse-server version (Be specific! Don't say 'latest'.) : 2.7.4
  • Operating System: Mac OS High Sierra 10.13.4 (17E202)
  • Hardware: 2015 MBP
  • Localhost or remote server? (AWS, Heroku, Azure, Digital Ocean, etc): Local

• Database

  • MongoDB version: ??
  • Storage engine: ??
  • Hardware: ??
  • Localhost or remote server? (AWS, mLab, ObjectRocket, Digital Ocean, etc): mLab

Logs/Trace

Cannot read property 'objectId' of undefined

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[JacobJT]

I believe this bug still exists, though I did see a more recent issue opened with a similar issue using matchesKeyInQuery

Unless this was recently solved as part of that bug, it should remain open.

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[JacobJT]

Posted fix in comments of #5030, will submit PR later fixing these issues (they are essentially the same).

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.