Fn.conditionIf(...).toString() fails to serialize in Java

[robwettach]

In CDK for Java 0.21.0, the FnIf condition extends Token, providing an implementation of toString() that performs as I expect: rendering the if-condition as a CloudFormation token string:

{
  "Fn::If": [
    "Condition",
    "IfTrue",
    "IfFalse"
  ]
}

After v0.21.0, specifically in the latest version 0.25.2, the new Fn.conditionIf method returns an IConditionExpression which does not extend Token or implement toString(). As such, when calling toString() on the result of Fn.conditionIf, which is required to pass the result of the condition to any "props" that expects a String, serializes the Java object directly:

"software.amazon.awscdk.IConditionExpression$Jsii$Proxy@3bbc39f8"

This makes CDK >0.21.0 unusable from Java if your stack expects to use "Fn::If". I believe that feat: cloudformation condition chaining (#1494) switched from returning an FnCondition, which extended CloudFormationToken, to returning IConditionExpression. Instead, it should simply have returned FnConditionBase, CloudFormationToken, or even just String.

[robwettach]

Here's a minimal example comparing CDK 0.21.0 to 0.25.2:
https://github.com/robwettach/cdk-1984-example

[zhangzhx]

I've seen this issue as well after upgrading to 0.25.

[eladb]

Fix: #2007

[williamwxz]

I have the same issue on version 0.22.x, I would like to have .toString() interface which can return either the value in true condition or false condition. Has it been fixed? Which version the issue was fixed?

[rix0rrr]

It will be released this week.