Can't get a CfnInstance with instance.getInstance()

🐛 Bug Report

What is the problem?

Can’t get a CfnInstance with instance.getInstance(). I was hoping to get a CfnInstance to see if I can pass it in to Targets of CfnMaintenanceWindowTargetProps.

Reproduction Steps

(let [app (new App)
      stack (new Stack app "stack" stack-props)
      vpc (new Vpc stack "vpc")
      instance (new Instance stack "server" instance-props)
      window (new CfnMaintenanceWindow stack "window" maintenance-window-props)
      target (new CfnMaintenanceWindowTarget stack "target" maintenance-window-target-props)]
  (.getInstance instance)
  (.synth app))

Verbose Log

Execution error (IllegalArgumentException) at com.fasterxml.jackson.databind.introspect.POJOPropertyBuilder/getSetter (POJOPropertyBuilder.java:497). Conflicting setter definitions for property “networkInterfaces”: software.amazon.awscdk.services.ec2.CfnInstance#setNetworkInterfaces(1 params) vs software.amazon.awscdk.services.ec2.CfnInstance#setNetworkInterfaces(1 params) class software.amazon.jsii.JsiiException

or

Execution error (IllegalArgumentException) at com.fasterxml.jackson.databind.introspect.POJOPropertyBuilder/getSetter (POJOPropertyBuilder.java:497). Conflicting setter definitions for property “blockDeviceMappings”: software.amazon.awscdk.services.ec2.CfnInstance#setBlockDeviceMappings(1 params) vs software.amazon.awscdk.services.ec2.CfnInstance#setBlockDeviceMappings(1 params)

Environment

• CDK CLI Version: 1.8.0 (build 5244f97)
• Module Version: 1.8.0.DEVPREVIEW
• OS: MacOS Mojave
• Language: Java

Other information

JsiiObjectMapper.java:	57	software.amazon.jsii.JsiiObjectMapper/treeToValue
JsiiObject.java:	111	software.amazon.jsii.JsiiObject/jsiiGet
Instance.java:	66	software.amazon.awscdk.services.ec2.Instance/getInstance
RestFn.java:	1523	clojure.lang.RestFn/invoke
AFn.java:	22	clojure.lang.AFn/run
AFn.java:	22	clojure.lang.AFn/run
Thread.java:	748	java.lang.Thread/run

[rix0rrr]

The reason probably being that the Java code contains an overloaded setter that Jackson can’t pick between:

    /**
     * `AWS::EC2::Instance.BlockDeviceMappings`.
     * 
     * @see http://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-properties-ec2-instance.html#cfn-ec2-instance-blockdevicemappings
     */
    @software.amazon.jsii.Stability(software.amazon.jsii.Stability.Level.External)
    public void setBlockDeviceMappings(final software.amazon.awscdk.core.IResolvable value) {
        this.jsiiSet("blockDeviceMappings", value);
    }

    /**
     * `AWS::EC2::Instance.BlockDeviceMappings`.
     * 
     * @see http://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-properties-ec2-instance.html#cfn-ec2-instance-blockdevicemappings
     */
    @software.amazon.jsii.Stability(software.amazon.jsii.Stability.Level.External)
    public void setBlockDeviceMappings(final java.util.List<java.lang.Object> value) {
        this.jsiiSet("blockDeviceMappings", value);
    }

[RomainMuller]

The fix for this will roll out in the next CDK release. I’ll resolve this issue for now, please re-open if you still encounter the problem once the new release (probably 1.19.0) is out.