Error "When you subscribe directly, you can't have other specified fields rather than $in" is unclear #416
Description
I have the following observer being created in my server, which I created to test something with Redis Oplog:
Collection.find({
_id: { $nin: ignoredIds },
'tests.firstTest': 1,
}, {
fields: {
_id: 1,
},
}).observe({
added: (doc) => {
const docId = doc._id;
doSomething(docId);
},
});However, it seems like this throws the following error:
uncaughtException Error: [When you subscribe directly, you can't have other specified fields rather than $in]
This error isn't very clear about what I'm doing wrong, and how I could solve it. I think the main issue is that the expression "subscribe directly" isn't immediately obvious.
We are currently avoiding to use $in and $nin expressions when creating observers outside of a publication, as we didn't get this error inside publications for some reason. But we're actually not sure what was going wrong, so we're not sure what specifically to avoid.