Receiving a HTTP 500 when using a distinct query on nullable field

[j-koenig]

Issue Description

Parse-Server responds with a HTTP 500 when using a distinct query on the _User table using a field which is set to null on one or more objects.

Steps to reproduce

Setup a new parse-server instance and add a field of the type String to the table. Create a new user and set the newly created field to null for the new user. Use the new distinct query feature on that field.

Expected Results

The server should return an array with all distinct strings

Actual Outcome

The server responds with a HTTP 500

Environment Setup

• Server

  • parse-server version: 2.7.2
  • Operating System: Amazon Linux 2017.09 v4.4.4
  • Hardware: EC2 t2.micro
  • Localhost or remote server: AWS

• Database

  • MongoDB version: 3.2.13
  • Storage engine: wiredTiger
  • Hardware: EC2 t2.micro
  • Localhost or remote server: AWS

Logs/Trace

Uncaught internal server error. TypeError: Cannot convert undefined or null to object
    at cleanResultOfSensitiveUserInfo (/var/app/current/node_modules/parse-server/lib/RestQuery.js:422:10)
    at config.database.find.then.results (/var/app/current/node_modules/parse-server/lib/RestQuery.js:499:9)
    at process._tickDomainCallback (internal/process/next_tick.js:135:7) TypeError: Cannot convert undefined or null to object
    at cleanResultOfSensitiveUserInfo (/var/app/current/node_modules/parse-server/lib/RestQuery.js:422:10)
    at config.database.find.then.results (/var/app/current/node_modules/parse-server/lib/RestQuery.js:499:9)
    at process._tickDomainCallback (internal/process/next_tick.js:135:7)

[dplewis]

Good catch! Would you like to open a PR for this issue?

[dplewis]

@flovilmart I have a PR ready for this but I wanted to verify something. I noticed a difference when setting a field from a value to null or undefined.

When using null the field is set.

{ $set: { fieldName: null, _updated_at: ... } }

When using undefined the field isn't updated.

{ $set: { _updated_at: ... } }

Is this proper behavior? This is specific for Mongo, they both update when using PG

[flovilmart]

it boils down to bottom values, undefined is not serialized, this is an unset, in PG null or unset is the same right?

[j-koenig]

@dplewis Sorry for not answering to your message and thanks for the PR :)

[jeffreyjackson]

how do we get a field back to 'undefined' when using unset in js sdk? now it sets it to null which isnt the same and breaks older versions. @flovilmart