🤞 I can't completely recall why we needed to pin this to v4, I suspect I was concerned about the polyfills introduced by mongodb/js-bson#550 (which got shipped as part of v5.0.0). Also, for context a PR, which will vendor a couple of these polyfills has merged but is yet to be published, we might want to wait for the release of that and support only v4 || v5.4.0 (or whatever that version will be).

To ensure we're testing with bson@5 we should probably add a devDependency to the SDK package (in addition to the peer dependency) as well as the integration tests package .. and you might need to bump the version in realm-web to avoid conflicting versions (which would potentially prevent bson from being hoisted to the root). We've had issues with value comparisons before, where the test app would use one version of bson while the SDK used a different one and value instanceof bson.ObjectId would be incorrectly false.

I'm surprised that users are seeing

Unable to resolve "bson" from "node_modules/realm/dist/bundle.react-native.mjs"

if they just allow NPM to install bson@v4 🤔 Perhaps it's related to that being a ESM, if so the change back to CJS might magically fix it.

@kraenhansen, thanks for some context PRs!

Regarding:

..we might want to wait for the release of that and support only v4 || v5.4.0..

If we'd wait, do you think it'd be okay to tell users to install v5+ but ignore the warning?

I'll make the bson ^5 a dev dependency in the SDK and tests, and do the change in realm-web as well.

Update: I've added to the PR description to wait with the merge until the related BSON changes are released.

I've updated the peerDependency to be ^4 || >=5.4.0. This should make sure we are always compatible and not have the polyfill issue

So one thing i've noted, is that if we have bson as a peerDependency than it will be required in the users project. I think this is not our intention, as this would break for most users as soon as they updated, since in older realm versions, bson was just a normal dependency. Therefore, I think we should change it to an optionalDependency to ensure that if a user is using their own version of bson, that it is within the compatible range for realm.

The React Native test are also failing for version 5.4.0. I believe there are missing polyfills. We may just have to revert to pinning this back to v4 and keeping it as an internal dependency.

Closing this (instead follow #6561).