CloudFront argument lost during synth

[cmclaughlin]

Community Note

• Please vote on this issue by adding a 👍 reaction to the original issue to help the community and maintainers prioritize this request
• Please do not leave "+1" or other comments that do not add relevant new information or questions, they generate extra noise for issue followers and do not help prioritize the request
• If you are interested in working on this issue or have submitted a pull request, please leave a comment

cdktf & Language Versions

• nodejs 12.22.7
• python 3.10.0
• cdktf 0.8.1
• cdktf-cdktf-provider-aws 3.0.1

Affected Resource(s)

CloudfrontDistributionDefaultCacheBehaviorForwardedValues has the problem

I find it interesting that CloudfrontDistributionOrderedCacheBehaviorForwardedValues does not have the problem, despite having a similar method signature, e.g. both have query_string as an argument.

Debug Output

Here's a repo that reproduce the problem:

https://github.com/cmclaughlin/cdktf-cloudfront-query-string-bug

Running cdktf deploy generates this Terraform error:

╷
│ Error: Missing required argument
│
│   on cdk.tf.json line 54, in resource.aws_cloudfront_distribution.cloudfronttest_distro_CAF0A17E.default_cache_behavior.forwarded_values:
│   54:           }
│
│ The argument "query_string" is required, but no definition was found.
╵

However, changing query_string on line 48 of main.py to True will get the plan to pass (but that's not the desired value)

Expected Behavior

Plan cleanly w/ query_string=False

Actual Behavior

Terraform Missing required argument error

Steps to Reproduce

• Clone https://github.com/cmclaughlin/cdktf-cloudfront-query-string-bug
• Setup a python virtualenv, install requirements, etc
• Run cdktf deploy

Important Factoids

We recently upgraded from cdktf 0.3 to 0.7.0. We didn't get very far with 0.7.0 before seeing more breaking changes in 0.8.0, so we upgraded to 0.8.1.

I haven't yet narrowed down when or where this problem started... but I don't think we had the problem prior to the recent upgrades.

[jsteinich]

I think this started with the change to having single item blocks omit the array. There have been a few fixes made since then, but it seems like this case slipped through the cracks.

I believe the issue is caused by

terraform-cdk/packages/@cdktf/provider-generator/lib/get/generator/emitter/struct-emitter.ts

Line 233 in 73a8394

this.code.openBlock(`if (this.${att.storageName})`);

This is doing a "truthy" test rather than an is defined test. I think we can simply update to check that it isn't undefined.

[github-actions]

I'm going to lock this issue because it has been closed for 30 days. This helps our maintainers find and focus on the active issues. If you've found a problem that seems similar to this, please open a new issue and complete the issue template so we can capture all the details necessary to investigate further.