Detailed diff duplicated collection diffs

[VenelinMartinov]

What happened?

Diffs when a non-empty collection is added/removed seem to be duplicated in the detailed diff output.

  ~ prov:index/test:Test: (update)
      [id=newid]
      [urn=urn:pulumi:test::test::prov:index/test:Test::mainRes]
    + listProps: [
    +     [0]: "val"
      ]
    + listProps: [
    +     [0]: "val"
      ]

Example

https://github.com/pulumi/pulumi-terraform-bridge/pull/2159/files

list added for an example

Output of pulumi about

.

Additional context

No response

Contributing

Vote on this issue by adding a 👍 reaction.
To contribute a fix for this issue, leave a comment (and link to your pull request, if you've opened one already).

[t0yv0]

Can we construct an AWS-based test case here? I can help.

[t0yv0]

import * as pulumi from "@pulumi/pulumi";
import * as aws from "@pulumi/aws";

const config = new pulumi.Config();

const step = config.requireNumber("step");

const lt = new aws.ec2.LaunchTemplate("lt", {
    blockDeviceMappings: step === 0 ? [] : [
        {deviceName: "/dev/sdf",
         ebs: {volumeSize: 20}},
    ],
});

export const ltId = lt.id;

#!/usr/bin/env bash

set -euo pipefail

pulumi destroy --yes

pulumi config set step 0
pulumi up --skip-preview

pulumi config set step 1
pulumi preview --diff
pulumi up --skip-preview

Getting:

    ~ aws:ec2/launchTemplate:LaunchTemplate: (update)
        [id=lt-00bf473f05c5f57b1]
        [urn=urn:pulumi:dev::pulumi-terraform-bridge-2234::aws:ec2/launchTemplate:LaunchTemplate::lt]
        [provider=urn:pulumi:dev::pulumi-terraform-bridge-2234::pulumi:providers:aws::default_6_45_0::5cd507c6-a81f-41e2-b8ba-494c8c29f190]
      ~ blockDeviceMappings: [
          + [0]: {
                  + deviceName: "/dev/sdf"
                  + ebs       : {
                      + volumeSize: 20
                    }
                }
        ]

Which appears reasonable. Any ideas why this doesn't reproduce on LaunchTemplate?

[VenelinMartinov]

Two things:

1. In the test case what happens is the property is changed from null to non-empty, not from empty to non-empty.
2. Had a look at the LaunchTemplate example and I believe this depends on the implementation of Create - if the create returns an empty list when the property is unspecified, the issue does not repro:

{
    "method": "/pulumirpc.ResourceProvider/Create",
    "request": {
        "urn": "urn:pulumi:dev::bridge_2234_aws::aws:ec2/launchTemplate:LaunchTemplate::lt",
        "properties": {
            "__defaults": [
                "name"
            ],
            "name": "lt-da69eeb"
        }
    },
    "response": {
        "id": "lt-015036d7e87cf914d",
        "properties": {
            "arn": "arn:aws:ec2:us-east-1:616138583583:launch-template/lt-015036d7e87cf914d",
            "blockDeviceMappings": [],
            "capacityReservationSpecification": null,
            "cpuOptions": null,
            "defaultVersion": 1,
            "description": "",
            "disableApiStop": false,
            "disableApiTermination": false,
            "ebsOptimized": "",
            "elasticGpuSpecifications": [],
            "elasticInferenceAccelerator": null,
            "enclaveOptions": null,
            "hibernationOptions": null,
            "iamInstanceProfile": null,
            "id": "lt-015036d7e87cf914d",
            "imageId": "",
            "instanceInitiatedShutdownBehavior": "",
            "instanceMarketOptions": null,
            "instanceRequirements": null,
            "instanceType": "",
            "kernelId": "",
            "keyName": "",
            "latestVersion": 1,
            "licenseSpecifications": [],
            "maintenanceOptions": null,
            "metadataOptions": null,
            "monitoring": null,
            "name": "lt-da69eeb",
            "namePrefix": "",
            "networkInterfaces": [],
            "placement": null,
            "privateDnsNameOptions": null,
            "ramDiskId": "",
            "securityGroupNames": [],
            "tagSpecifications": [],
            "userData": "",
            "vpcSecurityGroupIds": []
        }
    },
    "metadata": {
        "kind": "resource",
        "mode": "client",
        "name": "aws"
    }
}

This is what happens with LaunchTemplate.

[VenelinMartinov]

The issue seems to be fixed in #2379 - looks like we are duplicating the diff in the response to the engine in

pulumi-terraform-bridge/pkg/tfbridge/provider.go

Line 1159 in cf59a25

for path, diff := range dd.collectionDiffs {

[VenelinMartinov]

Removed from #2379 as out of scope, will revisit later.

[VenelinMartinov]

It turns out #2294 is not quite enough here.

This fixes lists and sets but we seem to be mishandling maps in MakeTerraformResult:

pulumi-terraform-bridge/pkg/tfbridge/schema.go

Line 1011 in 6b95c60

ctx context.Context,

See test in 51dd086#diff-5ecbec35cb8a03b89c5be410138532ea2da5904bfd52fdcb604d3b75414a6044R978

Nil and empty maps are both represented as an empty map by MakeTerraformResult. Should be fixable.

[VenelinMartinov]

Actually it turns out the nullness of maps is lost by PlanResourceChange here:

pulumi-terraform-bridge/pkg/tfshim/sdk-v2/provider2.go

Line 278 in 95cc5de

}

both prop and cfg there contain cty.NullVal(cty.Map(cty.String)) but PRC returns "map_prop":cty.MapValEmpty(cty.String)