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// Test that a transaction cannot write to a collection that has been dropped or created since the
// transaction started.
// @tags: [uses_transactions, uses_snapshot_read_concern]
(function() {
"use strict";
const dbName1 = "test1";
const dbName2 = "test2";
const collNameA = "coll_A";
const collNameB = "coll_B";
const sessionOutsideTxn = db.getMongo().startSession({causalConsistency: true});
const testDB1 = sessionOutsideTxn.getDatabase(dbName1);
const testDB2 = sessionOutsideTxn.getDatabase(dbName2);
testDB1.runCommand({drop: collNameA, writeConcern: {w: "majority"}});
testDB2.runCommand({drop: collNameB, writeConcern: {w: "majority"}});
const session = db.getMongo().startSession({causalConsistency: false});
const sessionDB1 = session.getDatabase(dbName1);
const sessionDB2 = session.getDatabase(dbName2);
const sessionCollA = sessionDB1[collNameA];
const sessionCollB = sessionDB2[collNameB];
//
// A transaction with snapshot read concern cannot write to a collection that has been dropped
// since the transaction started.
//
// Ensure collection A and collection B exist.
assert.commandWorked(sessionCollA.insert({}));
assert.commandWorked(sessionCollB.insert({}));
// Start the transaction with a write to collection A.
session.startTransaction({readConcern: {level: "snapshot"}});
assert.commandWorked(sessionCollA.insert({}));
// Drop collection B outside of the transaction. Advance the cluster time of the session
// performing the drop to ensure it happens at a later cluster time than the transaction began.
sessionOutsideTxn.advanceClusterTime(session.getClusterTime());
assert.commandWorked(testDB2.runCommand({drop: collNameB, writeConcern: {w: "majority"}}));
// We cannot write to collection B in the transaction, since it is illegal to implicitly create
// collections in transactions. The collection drop is visible to the transaction in this way,
// since our implementation of the in-memory collection catalog always has the most recent
// collection metadata.
assert.commandFailedWithCode(sessionCollB.insert({}),
ErrorCodes.OperationNotSupportedInTransaction);
assert.commandFailedWithCode(session.abortTransaction_forTesting(), ErrorCodes.NoSuchTransaction);
//
// A transaction with snapshot read concern cannot write to a collection that has been created
// since the transaction started.
//
// Ensure collection A exists and collection B does not exist.
assert.commandWorked(sessionCollA.insert({}));
testDB2.runCommand({drop: collNameB, writeConcern: {w: "majority"}});
// Start the transaction with a write to collection A.
session.startTransaction({readConcern: {level: "snapshot"}});
assert.commandWorked(sessionCollA.insert({}));
// Create collection B outside of the transaction. Advance the cluster time of the session
// performing the drop to ensure it happens at a later cluster time than the transaction began.
sessionOutsideTxn.advanceClusterTime(session.getClusterTime());
assert.commandWorked(testDB2.runCommand({create: collNameB}));
// We cannot write to collection B in the transaction, since it experienced catalog changes
// since the transaction's read timestamp. Since our implementation of the in-memory collection
// catalog always has the most recent collection metadata, we do not allow you to read from a
// collection at a time prior to its most recent catalog changes.
assert.commandFailedWithCode(sessionCollB.insert({}), ErrorCodes.SnapshotUnavailable);
assert.commandFailedWithCode(session.abortTransaction_forTesting(), ErrorCodes.NoSuchTransaction);
session.endSession();
}());
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