DOTNET PUBLISH doesn't add tags on docker container when using an environment variable that contains multiple tags

[keigezellig]

Describe the bug

I am using dotnet publish to create and publish a docker container for a Blazor WebApp. When setting the ContainerImageTag option through an environment variable which contains multiple tags (formatted according to the documentation), those tags are not put on the resulting docker image.
This occurs when building locally as well using the .net SDK docker to build the app in my CI/CD environment.

See screenshot below

To Reproduce

I created a minimal Blazor project (to be found here) that reproduces the issue in a couple of scenarios.
Run the deploy.sh to see what happens. The actual dotnet publish commands are also to found in this file.

Further technical details

Output of dotnet --info (my local system)

.NET SDK:
Version: 8.0.100
Commit: 57efcf1350
Workload version: 8.0.100-manifests.3b83835e

Runtime Environment:
OS Name: ubuntu
OS Version: 22.04
OS Platform: Linux
RID: linux-x64
Base Path: /usr/share/dotnet/sdk/8.0.100/

.NET workloads installed:
Workload version: 8.0.100-manifests.3b83835e
[maui-android]
Installation Source: SDK 8.0.100
Manifest Version: 8.0.3/8.0.100
Manifest Path: /usr/share/dotnet/sdk-manifests/8.0.100/microsoft.net.sdk.maui/8.0.3/WorkloadManifest.json
Install Type: FileBased

[wasm-tools]
Installation Source: SDK 8.0.100
Manifest Version: 8.0.0/8.0.100
Manifest Path: /usr/share/dotnet/sdk-manifests/8.0.100/microsoft.net.workload.mono.toolchain.current/8.0.0/WorkloadManifest.json
Install Type: FileBased

Host:
Version: 8.0.0
Architecture: x64
Commit: 5535e31a71

.NET SDKs installed:
8.0.100 [/usr/share/dotnet/sdk]

.NET runtimes installed:
Microsoft.AspNetCore.App 8.0.0 [/usr/share/dotnet/shared/Microsoft.AspNetCore.App]
Microsoft.NETCore.App 8.0.0 [/usr/share/dotnet/shared/Microsoft.NETCore.App]

Other architectures found:
None

Environment variables:
DOTNET_ROOT [/usr/share/dotnet]

global.json file:
Not found

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[baronfel]

Hi @keigezellig - what you've found here is actually a bug in our validation code. None of the ways you're passing multiple tags are making it through to the containerization targets. I've got a PR to fix this validation at #37832, but I'll have to dig for an example of correctly passing them through the command line. There's some other discussion here that may help: dotnet/sdk-container-builds#492 (comment)