Customer feedback | az stack sub validate | missing information | validate what, how, why?

[dbradish-microsoft]

Describe the bug

This GitHub issue is in response to MicrosoftDocs/azure-docs-cli customer feedback 4639.

Engineering request

Please add more information to the reference command description. What does this command validate? Why does a customer want to do this? Use the long-summary property if needed.

There is one conceptual article that uses the commands in this subgroup, Deployment stacks, but it doesn't address validation.

Customer feedback

Link:
https://learn.microsoft.com/en-us/cli/azure/stack/sub?view=azure-cli-latest#az-stack-sub-validate

Verbatim:
Here it says "Validate a deployment stack at subscription scope.", which sounds nice, but what are you validating? I don't understand what this command is doing at all.

If I change something in my bicep file or parameter file it just says "looks cool 👍" with a list of "validatedResources" (including resources that don't exist yet or that I modified)

I had hoped it would give me a list of what would change (but sadly, this doesn't seem to exist at all for deployment stacks?)...

Page URL
https://learn.microsoft.com/en-us/cli/azure/stack/sub?view=azure-cli-latest

Content source URL
https://github.com/MicrosoftDocs/azure-docs-cli/blob/main/latest/docs-ref-autogen/stack/sub.yml

Related command

az stack sub validate

Errors

n/a

Issue script & Debug output

n/a

Expected behavior

n/a

Environment Summary

Azure CLI 2.64.0

Additional context

No response

[yonzhan]

Thank you for opening this issue, we will look into it.

[dbradish-microsoft]

@yonzhan , Can you please assign this GitHub issue to the service team?

[dbradish-microsoft]

@sijuman, @sarathys, @bganapa, @rakku-ms, can you please comment on this customer feedback?

[torreymicrosoft]

Thanks for your patience — this was recently picked up as an outstanding open issue for the ARM Deployments team to review, and thanks @dbradish-microsoft for moving the doc feedback over.

There are two separate things in here:

1. The help text is too thin — agreed. az stack sub validate currently only says "Validate a deployment stack at subscription scope." What it actually does: it submits the stack's template + parameters to ARM for server-side preflight validation (template/parameter correctness and basic preflight) without creating or modifying the stack or its resources — much like az deployment sub validate, but for the stack operation. A potential path is to expand the command's long-summary to spell that out.

2. "It doesn't tell me what would change" — that's expected today: validate is a correctness check, not a change preview. The validatedResources list reflects what the stack would manage, not a diff, and deployment stacks don't currently expose a what-if/change-preview the way az deployment ... what-if does. That's a reasonable feature ask we can track on its own.

Does an expanded description along the lines of #1 cover the doc gap you raised? And if a change-preview for stacks is the real need, let us know and we'll capture it as a feature request.

Leaving this open as feature request not bug.

[torreymicrosoft]

@snarkywolverine @aperezmicrosoft for vis as this is Stacks related