Related issues

#1426 which is supposed to be fixed by #1432 which hasn't been merged yet. I am raising this issue again, because without the merge&release of the fix I do no consider it "fixed".

[REQUIRED] Version info

node: v16.15.0
firebase-functions: 4.6.0
firebase-tools: 12.4.0
firebase-admin: 10.2.0

[REQUIRED] Test case

import * as functions from 'firebase-functions';

export let test = functions
    .database
    .ref('/test/{id}')
    .onWrite((event, context) => console.log(event.after.child('nested/property').val()));

[REQUIRED] Steps to reproduce

Insert any value to realtime database at /test/123/whatever

[REQUIRED] Expected behavior

Calling event.after.child('nested/property').val()) should return null (as it does prior to v4)

[REQUIRED] Actual behavior

TypeError: Cannot read properties of null (reading 'property') at DataSnapshot.val (/workspace/node_modules/firebase-functions/lib/common/providers/database.js:104:32)

Were you able to successfully deploy your functions?

Yes, this is a runtime error.

Footnote

Since the v4 rewrote the exists() as a check to the result of val() it is also affected. And it's really not clear to me how else to check if the nested property exists.