[Python] TypeSpec migration for azure-mgmt-appcontainers

[msyyc]

[Python] TypeSpec migration breaking-change analysis for azure-mgmt-appcontainers

Sources

• Spec PR: Add TypeSpec versioning decorators for ContainerApps 2026-01-01 stable azure-rest-api-specs#42504
• Pre-migration swagger source: specification/app/resource-manager@2ed0a048
• Swagger API version: 2026-01-01 (default tag: package-2026-01-01)
• Generated with apiVersion: 2026-01-01 (matched from swagger default tag)

Summary

Bucket	Count
MITIGATED in spec	0
ACCEPTED (no mitigation)	All listed below

No spec mitigation PR was created — every breaking change matched an "Accept" pattern in the SDK breaking changes guide.

Accepted breaking changes

1. Pageable list-response models removed (Guide §8)

Python no longer surfaces named *Collection / *Result paging models for list operations. The following are removed:

AuthConfigCollection, AvailableOperations, AvailableWorkloadProfilesCollection, CertificateCollection, ConnectedEnvironmentCollection, ContainerAppCollection, DaprComponentsCollection, HttpRouteConfigCollection, JavaComponentsCollection, JobExecutionNamesCollection, JobsCollection, ListUsagesResult, MaintenanceConfigurationCollection, ManagedCertificateCollection, ManagedEnvironmentsCollection, RevisionCollection, SessionPoolCollection, SourceControlCollection, WorkflowEnvelopeCollection, WorkloadProfileStatesCollection

User impact: none — these were never user-instantiated; pagers return ItemPaged[<T>] as before.

2. Multi-level property flattening removed (Guide §11)

• MaintenanceConfigurationResource lost direct property scheduled_entries; access via the new nested .properties.scheduled_entries (new properties property added, new ScheduledEntries model added).

3. Header/query parameters → keyword-only (Guide §9)

• ContainerAppsOperations.list_custom_host_name_analysis: parameter custom_hostname changed from positional_or_keyword to keyword_only.

4. Enum singular rename: ExtendedLocationTypes → ExtendedLocationType

Same wire value ("CustomLocation"). Mitigation via @@clientName was attempted but the old ExtendedLocationTypes is still referenced by @typeChangedFrom in the versioned TypeSpec, causing a duplicate-client-name conflict; mitigation was reverted. Single-member enum, minimal surface, so accepted.

5. Container model __init__ signature: args parameter is now var_positional (*args)

Affects: BaseContainer, Container, InitContainer, JobExecutionContainer, SessionContainer.

The TypeSpec emitter treats the literal property name args specially (it is Python's conventional *args name), converting it from a keyword-only list parameter into variadic positional arguments. This is an emitter convention — applies uniformly across the 5 container models and is not addressable via @@clientName / @@override without renaming the wire property.

Migration: Container(args=["sh","-c"]) → Container("sh","-c") (or Container(args=...) is no longer valid).

Generated artifacts

• Swagger pre-migration SDK commit: 364ccc21e9
• TypeSpec post-migration SDK commit: 3449f008e8
• Changelog rename consolidation commit: f6bbb89740
• Spec head: 2f76edc6