[k8s-extension] 1.8.0 contains undocumented breaking changes: `az k8s-extension show` output shape and configurationSettings boolean serialization

[DanteMustCode]

Describe the bug

k8s-extension 1.8.0 (PR #10045, merged 2026-07-17, wheel published 2026-07-17
14:12 UTC) migrated the extensions operations to api-version 2025-03-01.

HISTORY.rst documents this only as:

Migrate Extensions api-version to 2025-03-01 and bump extension version to 1.8.0.

Two customer-visible behavioral changes shipped with it that are not mentioned anywhere,
and that the repo's automated breaking-change check does not detect (it only flagged the
new auto_upgrade_mode parameter).

Change 1 — az k8s-extension show output is no longer flattened

The 2023-05-01 msrest model declared the properties flattened:

"configuration_settings": {"key": "properties.configurationSettings", "type": "{str}"}

so the CLI emitted them at the top level. The 2025-03-01 TypeSpec model declares

properties: Optional["_models.ExtensionProperties"] = rest_field(...)

so they are now emitted nested under properties.

1.7.0

{ "configurationSettings": { ... }, "extensionType": "...", "provisioningState": "Succeeded" }

1.8.0

{ "properties": { "configurationSettings": { ... }, "extensionType": "...", "provisioningState": "Succeeded" } }

Any script doing az k8s-extension show ... --query configurationSettings or parsing the
JSON breaks. Python attribute access still works (the model keeps __flattened_items
compat), so this only bites consumers of the CLI output — which makes it easy to miss
in Python-level testing.

Change 2 — boolean configurationSettings values are no longer stringified

configuration_settings was typed {str} under msrest, so a Python bool passed by a
caller was coerced via str(). The TypeSpec model passes the value through to
json.dumps.

# 1.7.0
Serializer().serialize_data({"nvme.enabled": True}, "{str}")
# -> {'nvme.enabled': 'True'}

# 1.8.0
json.dumps(dict(ExtensionProperties(configuration_settings={"nvme.enabled": True})))
# -> {"configurationSettings": {"nvme.enabled": true}}

Values that used to round-trip as "True"/"False" now round-trip as "true"/"false".
This silently broke az aks ACStor support, which compares them against "True"
(filed as a separate issue on Azure/azure-cli). Other partner extensions that write
booleans through this field are likely affected the same way.

Related command

az k8s-extension show

Errors

Any script doing az k8s-extension show ... --query configurationSettings or parsing the
JSON breaks. Python attribute access still works (the model keeps __flattened_items
compat), so this only bites consumers of the CLI output — which makes it easy to miss
in Python-level testing.

Values that used to round-trip as "True"/"False" now round-trip as "true"/"false".
This silently broke az aks ACStor support, which compares them against "True"
(filed as a separate issue on Azure/azure-cli). Other partner extensions that write
booleans through this field are likely affected the same way.

Issue script & Debug output

az extension add --name k8s-extension --version 1.7.0
az k8s-extension show -g <rg> --cluster-name <cluster> \
    --cluster-type managedClusters --name <ext> --query configurationSettings   # works

az extension add --upgrade --name k8s-extension    # 1.8.0
az k8s-extension show -g <rg> --cluster-name <cluster> \
    --cluster-type managedClusters --name <ext> --query configurationSettings   # null

Expected behavior

Either the output shape and value serialization are preserved across the api-version
migration, or the change is called out as a breaking change in HISTORY.rst with a
migration note, and the major/minor version bump reflects it.

Suggested actions

1. Document both changes in HISTORY.rst for 1.8.0.
2. Consider restoring the flattened top-level output shape in the command layer for
   backwards compatibility (or emitting both).
3. Consider coercing configuration_settings values to str on the write path to
   preserve the previous wire format.
4. Consider whether the breaking-change CI rules can cover response-shape changes, not
   just command signatures.

Environment Summary

k8s-extension  1.7.0 -> 1.8.0
azure-cli      2.74.0 / 2.86.0 (both reproduce)

Additional context

No response

[yonzhan]

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