Errors from encodeValue_ are not caught and generate a UnhandledPromiseRejectionWarning

[WaldoJeffers]

Environment details

• OS: MacOSX 10.14.6
• Node.js version: v10.19.0
• npm version: 6.13.4
• @google-cloud/spanner version: 5.1.0

Bug description

Errors thrown by common-grpc/service/encodeValue_ like this one (passing undefined as value for a named parameter) are never caught by this function's caller, resulting in Unhandled Promise Rejections. Also, for some reason it seems to crash the underlying Node.js process.

The error thrown in encodeValue_ goes all the way to SessionPool.getReadSession where it fails to be caught:

• encodeValue_
• GrpcService.encodeValue_
• codec.encode
• Snapshot.encodeParams
• Snapshot.runStream
• Database.runStream
• SessionPool.getReadSession <-- Probably where the error should be caught

Steps to reproduce

There are probably different ways to reproduce the error; all you have to do is make the encodeValue_ helper throw. One way to achieve this is to provide an undefined value to a named parameter in a query

1. Run a query using named parameters, but don't pass a value to the parameter

const q = {
  json: true,
  params: { },
  sql: 'SELECT * FROM tableId WHERE namedParameter = @namedParameter',
};
const [rows] = await db.run(q); // This will lead to an Unhandled Promise rejection

So any attempt to catch the error will fail

const [rows] = await db.run(q).catch(() => console.log('I will never be called'));

But perhaps more unexpectedly, the code will stop running after this line:

const [rows] = await db.run(q).catch(() => console.log('I will never be called'));
console.log('Unreachable code is never called ???');

I am preparing a PR which might help fix the issue; but wanted to file the issue separately in case you prefer to fix the issue differently.

Thanks for your help :)

[AVaksman]

@WaldoJeffers the below snippet worked for me.

    const q = {
        json: true,
        sql: 'SELECT * FROM Singers WHERE SingerId=@id',
    }
    try {
        const [rows] = await database.run(q);
        console.log(rows.length);
        rows.forEach(console.log);
    } catch (error) {
        console.log('I will get called.')
        console.log('Error message => ' + error.message);
    }
    console.log('Continue execution here...');

I will get called.
Error message => 3 INVALID_ARGUMENT: No parameter found for binding: id
Continue execution here...

[WaldoJeffers]

Hello @AVaksman,

Thanks for your answer. Could try the same thing with

    const q = {
        json: true,
        params : { id: undefined }, // <-- Add this line (assuming both Singers & SingerId really exist)
        sql: 'SELECT * FROM Singers WHERE SingerId=@id',
    }
    try {
        const [rows] = await database.run(q);
        console.log(rows.length);
        rows.forEach(console.log);
    } catch (error) {
        console.log('I will get called.')
        console.log('Error message => ' + error.message);
    }
    console.log('Continue execution here...');

This does result in (node:8165) UnhandledPromiseRejectionWarning: Error: Value of type undefined not recognized. for me

[olavloite]

@WaldoJeffers Would you mind also having a look at #1208?

[WaldoJeffers]

Hello @olavloite ,

Thanks for your PR. It's probably a much better fix than my PR, but I'm not familiar enough with the codebase to provide feedback on the changes 😬