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  1. Core Server
  2. SERVER-58047

$toHashedIndexKey expression doesn't add any dependencies

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    • Fully Compatible
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    • v5.0, v4.4, v4.2
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      rs:PRIMARY> db.dropDatabase()
rs:PRIMARY> db.mycoll.insert({b: 2})
rs:PRIMARY> db.mycoll.aggregate([{$project: {b: {$toHashedIndexKey: "$b"}, _id: 0}}])
{ "b" : NumberLong("2338878944348059895") }
rs:PRIMARY> db.mycoll.aggregate([{$project: {b: {$toHashedIndexKey: "$b"}, _id: 1}}])
{ "_id" : ObjectId("60d3d020c102ff3ba60884a0"), "b" : NumberLong("848411777775835583") }
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      rs:PRIMARY> db.dropDatabase() rs:PRIMARY> db.mycoll.insert({b: 2}) rs:PRIMARY> db.mycoll.aggregate([{$project: {b: {$toHashedIndexKey: "$b"}, _id: 0}}]) { "b" : NumberLong("2338878944348059895") } rs:PRIMARY> db.mycoll.aggregate([{$project: {b: {$toHashedIndexKey: "$b"}, _id: 1}}]) { "_id" : ObjectId("60d3d020c102ff3ba60884a0"), "b" : NumberLong("848411777775835583") }
    • Sharding 2021-06-28
    • 1

      ExpressionToHashedIndexKey::_doAddDependencies() doesn't add the dependencies of its _children[0] expression. This causes the $project stage to incorrectly treat the field path expression as a missing value and hash it to the value of an explicit null value.

      void ExpressionToHashedIndexKey::_doAddDependencies(DepsTracker* deps) const {
    // Nothing to do
}

            Assignee:
            kshitij.gupta@mongodb.com Kshitij Gupta
            Reporter:
            max.hirschhorn@mongodb.com Max Hirschhorn
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              Created:
              Updated:
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