—
name: 🐞 Bug
about: For the mac build version of pymongo, the mergeObjects expression does not seem to be included in the build. The mergeObjects expression works for the windows build.
title: '[BUG] $mergeObjects not a recognized expression'

—

1. 1. 1. Current Behavior:

We have a dataset with a nested object. We want to group by an id and have the nested object at the id level. We then want to merge those objects to a list and output that list.
For the aggregation query:

pipeline = [
    {
        "$match": {
            ...
        }
    },
    ...
    {
        "$group": {
            "_id": {
                "id": "$id"
            },
            "nestedObject": {"$first": "$$ROOT"}
        }
    },
    ...
    {
        "$replaceRoot": {
            "newRoot": {"$mergeObjects": ["$otherDataset"]}
        }
    }
]

The following error occurs:

E pymongo.errors.OperationFailure: Unrecognized expression '$mergeObjects'

/Users/<user>/opt/miniconda3/envs/<env>/lib/python3.9/site-packages/pymongo/helpers.py:159: OperationFailure

1. 1. 1. Expected Behavior:
         The mergeObjects should be a recognized operation and the query about should work

1. 1. 1. Environment:

• OS: Big Sur 11.6
• Python: 3.9.7
• Pymongo: 3.11.3

Thank you for your help in this matter