PublishAsDockerFile callback drops generated container args in Helm deployment

[johanndev]

• I have searched the existing issues

Describe the bug

When publishing a single Python resource to Helm using aspire publish -o publish, container startup args are generated as expected.

If I add an empty PublishAsDockerFile callback, the Dockerfile is still generated correctly, but the args block disappears from publish/templates/app/deployment.yaml.

This looks like a regression/side-effect because only the callback was added and all other deployment content remains effectively unchanged.

Expected Behavior

Adding an empty PublishAsDockerFile callback should not change generated container runtime args in the Helm deployment manifest.

I expect this block to still be present:

args:
  - "main:app"
  - "--host"
  - "0.0.0.0"
  - "--port"
  - "8000"

Steps To Reproduce

Minimal AppHost:

var builder = Aspire.Hosting.DistributedApplication.CreateBuilder(args);

builder.AddUvicornApp("app", "./app", "main:app")
    .WithUv()
    .PublishAsDockerFile(configure =>
    {
    });

builder.AddKubernetesEnvironment("k8s");

builder.Build().Run();

1. Run aspire publish -o publish-with-callback with the AppHost above.
2. Inspect publish-with-callback/templates/app/deployment.yaml.
3. Observe there is no args section under the app container.
4. Remove only .PublishAsDockerFile(configure => { }) from the chain.
5. Run aspire publish -o publish-no-callback.
6. Inspect publish-no-callback/templates/app/deployment.yaml.
7. Observe args is present:
   • main:app
   • --host
   • 0.0.0.0
   • --port
   • 8000

Observed in controlled local repro:

• WITH_CALLBACK_ARGS=False
• WITHOUT_CALLBACK_ARGS=True

Exceptions (if any)

No exception is thrown.

Aspire doctor output

Aspire Environment Check
========================

.NET SDK
  ✅ .NET 11.0.100-preview.3.26207.106 installed (x64)  

Container Runtime
  ⚠️ Podman: installed but not running ← active  
       Start Podman service: sudo systemctl start podman       

Environment
  ✅ HTTPS development certificate is trusted  

Summary: 2 passed, 1 warnings, 0 failed
For detailed prerequisites: https://aka.ms/aspire-prerequisites

Anything else?

• .NET SDK: 11.0.100-preview.3.26207.106
• Aspire CLI: 13.3.0+4517e4a1ffb7f00a4c0e66882c2db952d637c0cc
• AppHost SDK: Aspire.AppHost.Sdk/13.3.0
• Package refs:
  • Aspire.Hosting.Kubernetes 13.3.0-preview.1.26256.5
  • Aspire.Hosting.Python 13.3.0
• OS: Windows
• Tooling: VS Code + CLI

AI disclosure: this issue report was prepared with assistance from GitHub Copilot (GPT-5.3-Codex), and all technical observations were verified locally.

[joperezr]

@mitchdenny can you please take a look? PublishAsDockerFile callback dropping container args in Helm deployment is in your area. (Note: #16874 looks like a duplicate of this one.)