[cloud_firestore] Not possible to merge set calls with Firestore transactions

[kroikie]

Merging set calls using transactions is currently not possible in Flutter because we don't have a SetOptions class and parameter for the set() method.

However, the docs stay otherwise:

    /// Writes to the document referred to by the provided [DocumentReference].
    /// If the document does not exist yet, it will be created. If you pass
    /// SetOptions, the provided data can be merged into the existing document.
      Future<void> set(
      ///.....

Issue was also posted on StackOverflow: https://stackoverflow.com/questions/57202980/unable-to-merge-a-transaction-set-with-setoptions

Doctor

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• No issues found!

[kroikie]

@mpivchev

The issue at flutter/flutter#36950 has been closed and moved here. Future collaboration on this issue will be done here.

[willvlad]

Same issue here! Any ETA?

[GRpro]

Any updates on this? Also faced an issue.

[andrsdev]

Same problem here!!!

[willhaslett]

I'm sure that the Flutter team has an abundance of important issues to address, but supporting all basic CRUD operations for the SDK's supported backend seems fundamental. Is there a plan for this?

[Ehesp]

Looks like support is available in the document reference but not the set of the transaction. Tracking it as high-priority.

[Ehesp]

A dirty workaround for now would be to read the document contents and merge the data together inside of the set until this gets fixed - not ideal but until this gets fixed it's the only solution.

[willhaslett]

@Ehesp Could that merging workaround be implemented on the backend using the .onWrite() hook in a Cloud Function, since that function has both the pre and post versions of the document available to it?

[Bobthebuilder24]

Can the update operation be changed to support this case? Making it merge if existing, and creating if not present?

[Ehesp]

This is being sorted as part of #2582

It'll also include merge and mergeFields.

[Salakar]

Hey, as part of our on-going work for #2582, support for SetOptions on Transaction.set has been added in our Firebase Firestore rework (#2913) - which has now been merged into master. We'll look at publishing some prereleases in the next few days. Thank you