Error: Exactly one of `[container]` or `[containers]` must be provided

What happened?

The same Pulumi program that succeeds in TS fails in Java:

Diagnostics:
  pulumi:pulumi:Stack (karol-issue-2-java-dev):
    Error: Exactly one of [container] or [containers] must be provided: Error: Exactly one of [container] or [containers] must be provided
        at normalizeTaskDefinitionContainers (/snapshot/awsx/bin/ecs/containers.js:37:15)
        at new FargateTaskDefinition (/snapshot/awsx/bin/ecs/fargateTaskDefinition.js:34:79)
        at new FargateService (/snapshot/awsx/bin/ecs/fargateService.js:40:30)
        at awsx:ecs:FargateService (/snapshot/awsx/bin/resources.js:25:45)
        at construct (/snapshot/awsx/bin/resources.js:43:12)
        at Provider.construct (/snapshot/awsx/bin/index.js:39:52)
        at Server.<anonymous> (/snapshot/awsx/node_modules/@pulumi/pulumi/provider/server.js:315:52)
        at Generator.next (<anonymous>)
        at fulfilled (/snapshot/awsx/node_modules/@pulumi/pulumi/provider/server.js:18:58)
        at processTicksAndRejections (node:internal/process/task_queues:96:5)

I believe this might be because TS (and all other SDKs use the new serializer path, the keepOutputValues (specialOutputValueSig) and Java uses the old output serializer.

We can also see this is Besom Scala SDK, that uses the old serializer.

Example

The failing Java program:

package myproject;

import com.pulumi.Context;
import com.pulumi.Pulumi;
import com.pulumi.aws.ecs.Cluster;
import com.pulumi.aws.lb.LoadBalancer;
import com.pulumi.awsx.ecs.FargateService;
import com.pulumi.awsx.ecs.FargateServiceArgs;
import com.pulumi.awsx.ecs.inputs.FargateServiceTaskDefinitionArgs;
import com.pulumi.awsx.ecs.inputs.TaskDefinitionContainerDefinitionArgs;
import com.pulumi.awsx.ecs.inputs.TaskDefinitionPortMappingArgs;
import com.pulumi.awsx.lb.ApplicationLoadBalancer;
import com.pulumi.core.Output;

public class App {
    public static void main(String[] args) {
        Pulumi.run(App::stack);
    }

    private static void stack(Context ctx) {
        var cluster = new Cluster("cluster");

        var loadBalancer = new ApplicationLoadBalancer("lb");

        var service = new FargateService("app-service", FargateServiceArgs.builder()
                .cluster(cluster.arn())
                .assignPublicIp(true)
                .taskDefinitionArgs(FargateServiceTaskDefinitionArgs.builder()
                        .container(TaskDefinitionContainerDefinitionArgs.builder()
                                .name("test")
                                .image("nginx:latest")
                                .cpu(256)
                                .memory(512)
                                .portMappings(
                                        TaskDefinitionPortMappingArgs.builder()
                                                .containerPort(80)
                                                .targetGroup(loadBalancer.defaultTargetGroup())
                                                .build()
                                )
                                .build()
                        ).build()
                )
                .desiredCount(1)
                .build()
        );

        ctx.export("frontendURL",
                Output.format("http://%s", loadBalancer.loadBalancer().apply(LoadBalancer::dnsName))
        );
        ctx.export("url", service.urn());
    }
}

And the working TypeScript:

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

// Create an ECS cluster
const cluster = new aws.ecs.Cluster("my-cluster", {});

// Create a load balancer to listen for requests and route them to the container.
const loadBalancer = new awsx.lb.ApplicationLoadBalancer("loadbalancer", {});

// Create a Fargate service running on the cluster, referencing the task definition
const service = new awsx.ecs.FargateService("app-service", {
  cluster: cluster.arn,
  assignPublicIp: true,
  taskDefinitionArgs: {
      container: {
        name: "test",
        image: "nginx:latest",
        cpu: 256,
        memory: 512,
        portMappings: [{
            containerPort: 80,
            targetGroup: loadBalancer.defaultTargetGroup,
        }],
      }
    },
  desiredCount: 1, // Number of tasks to run
});

// Export the URL of the service
export const frontendURL = pulumi.interpolate `http://${loadBalancer.loadBalancer.dnsName}`;
export const url = service.urn;

Output of pulumi about

TypeScript

pulumi about
CLI
Version      3.107.0
Go Version   go1.22.0
Go Compiler  gc

Plugins
NAME    VERSION
aws     6.24.0
awsx    2.5.0
docker  4.5.1
docker  3.6.1
nodejs  unknown

Host
OS       darwin
Version  14.2.1
Arch     arm64

This project is written in nodejs: executable='/opt/homebrew/bin/node' version='v21.6.2'

Backend
Name           pulumi.com
URL            https://app.pulumi.com/pprazak
User           pprazak
Organizations  pprazak, besom
Token type     personal

Dependencies:
NAME            VERSION
typescript      4.9.5
@pulumi/aws     6.24.0
@pulumi/awsx    2.5.0
@pulumi/docker  4.5.1
@pulumi/pulumi  3.107.0
@types/node     18.19.19

Pulumi locates its logs in /var/folders/n6/bg1skjsj3k7_1tjvn7n65zl40000gn/T/ by default
warning: Failed to get information about the current stack: No current stack

Java

pulumi about
CLI
Version      3.107.0
Go Version   go1.22.0
Go Compiler  gc

Plugins
NAME    VERSION
aws     6.24.0
awsx    2.5.0
docker  4.5.0
java    unknown

Host
OS       darwin
Version  14.2.1
Arch     arm64

This project is written in java: executable='/opt/homebrew/opt/sdkman-cli/libexec/candidates/java/current/bin/java' version='openjdk 21.0.1 2023-10-17
OpenJDK Runtime Environment GraalVM CE 21.0.1+12.1 (build 21.0.1+12-jvmci-23.1-b19)
OpenJDK 64-Bit Server VM GraalVM CE 21.0.1+12.1 (build 21.0.1+12-jvmci-23.1-b19, mixed mode, sharing)' java='/opt/homebrew/opt/sdkman-cli/libexec/candidates/java/current/bin/java' javac='21.0.1' maven='Apache Maven 3.9.6 (bc0240f3c744dd6b6ec2920b3cd08dcc295161ae)' gradle='8.6'

Current Stack: pprazak/karol-issue-2-java/dev

Found no resources associated with dev

Found no pending operations associated with dev

Backend
Name           pulumi.com
URL            https://app.pulumi.com/pprazak
User           pprazak
Organizations  pprazak, besom
Token type     personal

No dependencies found

Pulumi locates its logs in /var/folders/n6/bg1skjsj3k7_1tjvn7n65zl40000gn/T/ by default

Additional context

None.

Contributing

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

Start by reproducing the provided Java FargateService example and compare its old output serializer with the TypeScript path using keepOutputValues and specialOutputValueSig. Trace the serializer input reaching normalizeTaskDefinitionContainers and verify that the Java example no longer reports the container/containers error; the payload names no repository files or tests.