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/**
* Tests that change streams can be opened on a namespace before the collection or database has been
* created, and will not implicitly create either.
*/
(function() {
"use strict";
load("jstests/libs/change_stream_util.js"); // For 'ChangeStreamTest'.
// Ensure that the test DB does not exist.
const testDB = db.getSiblingDB(jsTestName());
assert.commandWorked(testDB.dropDatabase());
let dbList = assert.commandWorked(
db.adminCommand({listDatabases: 1, nameOnly: true, filter: {name: testDB.getName()}}));
assert.docEq(dbList.databases, []);
const collName = "test";
// Start a new $changeStream on the non-existent db.
const cst = new ChangeStreamTest(testDB);
const changeStreamCursor =
cst.startWatchingChanges({pipeline: [{$changeStream: {}}], collection: collName});
// Confirm that a $changeStream cursor has been opened on the namespace.
assert.gt(changeStreamCursor.id, 0);
// Confirm that the database has not been implicitly created.
dbList = assert.commandWorked(
db.adminCommand({listDatabases: 1, nameOnly: true, filter: {name: testDB.getName()}}));
assert.docEq(dbList.databases, []);
// Confirm that a non-$changeStream aggregation on the non-existent database returns an empty
// cursor.
const nonCsCmdRes = assert.commandWorked(
testDB.runCommand({aggregate: collName, pipeline: [{$match: {}}], cursor: {}}));
assert.docEq(nonCsCmdRes.cursor.firstBatch, []);
assert.eq(nonCsCmdRes.cursor.id, 0);
// Now perform some writes into the collection...
assert.commandWorked(testDB[collName].insert({_id: 1}));
assert.commandWorked(testDB[collName].insert({_id: 2}));
assert.commandWorked(testDB[collName].update({_id: 1}, {$set: {updated: true}}));
assert.commandWorked(testDB[collName].remove({_id: 2}));
// ... confirm that the database has been created...
dbList = assert.commandWorked(
db.adminCommand({listDatabases: 1, nameOnly: true, filter: {name: testDB.getName()}}));
assert.docEq(dbList.databases, [{name: testDB.getName()}]);
// ... and verify that the changes are observed by the stream.
const expectedChanges = [
{
documentKey: {_id: 1},
fullDocument: {_id: 1},
ns: {db: testDB.getName(), coll: collName},
operationType: "insert"
},
{
documentKey: {_id: 2},
fullDocument: {_id: 2},
ns: {db: testDB.getName(), coll: collName},
operationType: "insert"
},
{
documentKey: {_id: 1},
ns: {db: testDB.getName(), coll: collName},
updateDescription: {removedFields: [], updatedFields: {updated: true}},
operationType: "update"
},
{
documentKey: {_id: 2},
ns: {db: testDB.getName(), coll: collName},
operationType: "delete"
},
];
cst.assertNextChangesEqual({cursor: changeStreamCursor, expectedChanges: expectedChanges});
cst.cleanUp();
})();
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