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GraphQL: null on GraphQL API layer should be converted to {__op: "Delete"} #7648
Description
New Issue Checklist
- I am not disclosing a vulnerability.
- I am not just asking a question.
- I have searched through existing issues.
- I can reproduce the issue with the latest version of Parse Server.
Issue Description
Currently null values used during GraphQL mutation are not transformed by the GraphQL layer, so null is directly saved into the database. null in database could lead to unwanted behavior since query like exists: false will not resolve when the field has a null value.
Currently the GraphQL API has a lack of support to correctly unset fields. We should transform null to op Delete
Steps to reproduce
- Create an object via graphql
- Update a field to null
- Query the field object with
exists: false - Query will not resolve the object
Actual Outcome
null is saved into the DB
Expected Outcome
Null should transformed to undefined into the DB through the GraphQL API
Environment
alpha 5.0
Server
- Parse Server version:
alpha 5.0 - Operating system:
macOs - Local or remote host (AWS, Azure, Google Cloud, Heroku, Digital Ocean, etc):
local
Database
- System (MongoDB or Postgres):
mongo - Database version:
4.4 - Local or remote host (MongoDB Atlas, mLab, AWS, Azure, Google Cloud, etc):
local
Activity
parse-github-assistant commentedon Oct 19, 2021
Thanks for opening this issue!
mtrezza commentedon Oct 19, 2021
This is expected and well-known behavior. A
nullvalue is not the same asundefined. A developer is expected to be aware of that, and there are use cases in which this differentiation is desired. The Parse SDKs account for that differentiation. For example, in the JS SDK there is a distinction betweenobj.set("key", null);andobj.unset("key");. See #7518 (comment).Moumouls commentedon Oct 19, 2021
So here following the official spec of GraphQL
nullvalue in the input SHOULD delete the field in the database.Spec ref: https://spec.graphql.org/June2018/#sec-Null-Value
Agree, but GraphQL API could not handle this diff, currently a developer with the GraphQL API can't know if the field is undefined or null, and graphql will never support this 2 values. Here the special case with the strict null check should be handled with the SDK or cloud code.
But we need to let the developer unset the field via null value as expected by the official GraphQL Doc. And avoid a custom system with some
unlinkunsetworkarounds 🙂 (also hard to maintain)Later if a developer need to know if the field value is really "null" (non sense in a graphql use case since the response will not change), we could introduce a query
{field: {isNull: false}}or something similarMoumouls commentedon Oct 19, 2021
PR sent
mtrezza commentedon Oct 19, 2021
Interesting, looking at the GraphQL spec it seems you are correct. Reclassified this as a bug since the current behavior seems to violate the GraphQL specs.
parseplatformorg commentedon Oct 27, 2021
🎉 This change has been released in version 5.0.0-alpha.2
parseplatformorg commentedon Nov 1, 2021
🎉 This change has been released in version 5.0.0-beta.1
parseplatformorg commentedon Mar 14, 2022
🎉 This change has been released in version 5.0.0