(function() { 'use strict' ; function runTest() { db.test.drop(); db.test.insert({ _id: 1, "states" : [{x: 1, y: 1}, {x: 2, y: 2}]}); let result = db.test.runCommand({find: "test" , filter: {_id: 1 , states: { "$elemMatch" : {x: 1, "y" : { "$exists" : true }}}}, projection: { "states.$" : 1 }, limit: 1, singleBatch: true }); assert .eq(result.cursor.firstBatch.length, 1, "firstBatch is empty" ); assert .eq(result.cursor.firstBatch[0].states.length, 1, "states array is empty" ); assert .eq(result.cursor.firstBatch[0].states[0].x, 1, "unexpected 'states' document returned" ); } printjson( "Run test with SBE disabled" ); assert .commandWorked( db.adminCommand({setParameter: 1, internalQueryForceClassicEngine: true })); runTest(); printjson( "Run test with SBE enabled" ); assert .commandWorked( db.adminCommand({setParameter: 1, internalQueryForceClassicEngine: false })); runTest(); }());