Cannot call a method that takes an empty struct from Python

[skinny85]

🐛 Bug Report

Affected Languages

• TypeScript or Javascript
• Python
• Java
• .NET (C#, F#, ...)
• Go

General Information

• JSII Version: 1.29.0
• Platform: Darwin 186590cdb71d.ant.amazon.com 18.7.0 Darwin Kernel Version 18.7.0: Mon Mar 8 22:11:48 PST 2021; root:xnu-4903.278.65~1/RELEASE_X86_64 x86_64

What is the problem?

We have the following interface set in CDK's RDS library:

export interface IParameterGroup extends IResource {
  bindToCluster(options: ParameterGroupClusterBindOptions): ParameterGroupClusterConfig;

  bindToInstance(options: ParameterGroupInstanceBindOptions): ParameterGroupInstanceConfig;

  // doesn't matter...
}

export interface ParameterGroupClusterBindOptions {
}

export interface ParameterGroupClusterConfig {
  readonly parameterGroupName: string;
}

export interface ParameterGroupInstanceBindOptions {
}

export interface ParameterGroupInstanceConfig {
  readonly parameterGroupName: string;
}

export class ParameterGroup extends Resource implements IParameterGroup {
  // ...

Turns out, you can't call the bindToCluster() and bindToInstance() methods at all from Python.

Assuming we have this:

        parameter_group = rds.ParameterGroup(
            self, 'ParameterGroup',
            engine=rds.DatabaseInstanceEngine.maria_db(
                version=rds.MariaDbEngineVersion.VER_10_0_17,
            ),
        )

Calling parameter_group.bind_to_cluster() with no arguments fails with:

TypeError: Don't know how to convert object to JSON: ParameterGroupClusterBindOptions()

Calling parameter_group.bind_to_cluster() with either rds.ParameterGroupClusterBindOptions(), or {}, fails with:

TypeError: bind_to_cluster() takes 1 positional argument but 2 were given

[NGL321]

I have updated priority to match the related CDK issue

[schematis]

Any ETA on a fix for this?

[RomainMuller]

Ah - the problem boils down to {} being False-y in Python, I think. It's a trivial fix.

[github-actions]

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