Yes, the order of documents will be the same as the order of elements in the array and the order pre-unwind will be preserved.
Thanks for sharing this statement, and I gather you are a very reputable source, having worked on the aggregation framework itself.
It seems a colleague of yours contradicted this statement in a different forum thread a few months later sayng “MongoDB only gurantee order of documents based on a sort operation” which leaves me unsure whether it would be safe to avoid a sort operation (for performance reasons) when performing $unwind
Is there any up-to-date definititve documentation on what guarantees there are regarding array ordering during aggregation?