Do not allow prepareTransaction to prepare transactions without operations

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    • Type: Bug
    • Resolution: Fixed
    • Priority: Major - P3
    • 4.1.1
    • Affects Version/s: None
    • Component/s: None
    • Fully Compatible
    • ALL
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      ./mongod --replSet rs --setParameter enableTestCommands=1

      And in the shell:

      rs.initiate();

let session = db.getMongo().startSession({causalConsistency: false});
let sessionDB = session.getDatabase('test');

db.test.insert({a: 1});

assert.commandWorked(sessionDB.runCommand({
 find: 'test',
 readConcern: {level: 'snapshot'},
 txnNumber: NumberLong(0),
 startTransaction: true,
 autocommit: false
 }));

assert.commandWorked(sessionDB.adminCommand(
 {prepareTransaction: 'test', txnNumber: NumberLong(0), autocommit: false}));
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      ./mongod --replSet rs --setParameter enableTestCommands=1 And in the shell: rs.initiate(); let session = db.getMongo().startSession({causalConsistency: false }); let sessionDB = session.getDatabase( 'test' ); db.test.insert({a: 1}); assert.commandWorked(sessionDB.runCommand({ find: 'test' , readConcern: {level: 'snapshot' }, txnNumber: NumberLong(0), startTransaction: true , autocommit: false })); assert.commandWorked(sessionDB.adminCommand( {prepareTransaction: 'test' , txnNumber: NumberLong(0), autocommit: false }));
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      The onTransactionPrepare opObserver early-returns when there are no statements in the transaction. If a "find" transaction is started, and later prepared, this should not be legal if there are no statements to prepare.

      Session::prepareTransaction calls WriteUnitOfWork::prepare() regardless of whether or not a prepare optime was generated. This leads RecoveryUnit::prepareUnitOfWork to be called when no prepare timestamp has been set, causing this invariant failure

      Prepare should either a) be a no-op or b) return an error when there are no operations to prepare

            Assignee:
            Judah Schvimer
            Reporter:
            Louis Williams
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              Created:
              Updated:
              Resolved: