Lazy still broken in Python

[serverlessunicorn]

🐛 Bug Report

The following fails on CDK 1.49.1:
class Foo:
def produce(me, context):
return self.api.rest_api_id
lazy = core.Lazy.string_value(Foo())
with the error: AttributeError: type object 'Foo' has no attribute 'jsii_type'

Possibly recurrence or variant of 807 (#807)

Affected Languages

• TypeScript or Javascript
• [X ] Python
• Java
• .NET (C#, F#, ...)

General Information

• JSII Version: CDK version is 1.49.1
• Platform: Darwin MacBook-Pro.local 19.5.0 Darwin Kernel Version 19.5.0: Tue May 26 20:41:44 PDT 2020; root:xnu-6153.121.2~2/RELEASE_X86_64 x86_64

What is the problem?

Lazy in AWS CDK Python appears to have a jsii serialization problem; see discussion in 807.

Verbose Log

Traceback (most recent call last):
File "deploy.py", line 80, in
deployer.deploy()
File "deploy.py", line 63, in deploy
cdk = cdkstack.CdkStack(scope=app, id='VendiaShareDeployer',
File "/Users/timwagner/Desktop/projects/vendia/src/share/venv/lib/python3.8/site-packages/jsii/_runtime.py", line 66, in call
inst = super().call(*args, **kwargs)
File "/Users/timwagner/Desktop/projects/vendia/src/share/server/deploy/cdkstack.py", line 32, in init
lazy = core.Lazy.string_value(Foo())
File "/Users/timwagner/Desktop/projects/vendia/src/share/venv/lib/python3.8/site-packages/aws_cdk/core/init.py", line 6313, in string_value
return jsii.sinvoke(cls, "stringValue", [producer, options])
File "/Users/timwagner/Desktop/projects/vendia/src/share/venv/lib/python3.8/site-packages/jsii/_kernel/init.py", line 113, in wrapped
return _recursize_dereference(kernel, fn(kernel, *args, **kwargs))
File "/Users/timwagner/Desktop/projects/vendia/src/share/venv/lib/python3.8/site-packages/jsii/_kernel/init.py", line 311, in sinvoke
args=_make_reference_for_native(self, args),
File "/Users/timwagner/Desktop/projects/vendia/src/share/venv/lib/python3.8/site-packages/jsii/_kernel/init.py", line 124, in _make_reference_for_native
return [_make_reference_for_native(kernel, i) for i in d]
File "/Users/timwagner/Desktop/projects/vendia/src/share/venv/lib/python3.8/site-packages/jsii/_kernel/init.py", line 124, in
return [_make_reference_for_native(kernel, i) for i in d]
File "/Users/timwagner/Desktop/projects/vendia/src/share/venv/lib/python3.8/site-packages/jsii/_kernel/init.py", line 151, in _make_reference_for_native
kernel.create(d.class, d)
File "/Users/timwagner/Desktop/projects/vendia/src/share/venv/lib/python3.8/site-packages/jsii/_kernel/init.py", line 226, in create
fqn=klass.jsii_type or "Object",
AttributeError: type object 'Foo' has no attribute 'jsii_type'

[serverlessunicorn]

Ah, so perhaps this is an AWS CDK issue: The example at https://docs.aws.amazon.com/cdk/latest/guide/tokens.html (with Python selected) fails as written, but if you use the example from #807 and add @jsii.implements(core.IStringProducer) as an annotation to the producing class, it succeeds with the workaround.

[github-actions]

This issue has not received any attention in 2 years. If you want to keep this issue open, please leave a comment below and auto-close will be canceled.

[mschwab12]

This seems stil an issue. Can you reopen this bug?

[teemu-laakso]

I found a workaround for this bug. The following allows for synth time creation of any constructs with a callback:

class LazyCallback:
    __jsii_type__ = None

    def __init__(self, callback):
        self.callback = callback

    @jsii.member(jsii_name='produce')
    def produce(self, context):
        return self.callback()