Make channelData subfields optional to avoid throw

[Corina (corinagum)]

Fixes #563

The Teams service can send nested channelData objects as empty objects ( {} ). Because AppInfo.id was required, Pydantic raised a ValidationError, and since ActivityTypeAdapter.validate_python has no fallback, the entire activity was rejected, so affected bots silently stopped responding.

Reported against 2.0.15, the first release containing #504. Confirmed to affect customers, currently in 1:1 chats, with exposure growing as an upstream server-side rollout ramps.

Root cause

channelData.app is optional, so an absent app was always fine, but a present but empty one wasn't. Auditing the model graph showed this isn't unique to app: 98 sites exist where an optional parent points at a child with required fields. Seven were reachable from a plain message activity:

channelData.app={}       -> channelData.app.id            Field required
channelData.channel={}   -> channelData.channel.id        Field required
channelData.team={}      -> channelData.team.id           Field required
channelData.tenant={}    -> channelData.tenant.id         Field required
channelData.settings={}  -> channelData.settings.selectedChannel
attachments=[{}]         -> attachments.0.contentType
entities=[{}]            -> entities.0._unknown.type

Change

Make these inbound-only fields optional: AppInfo.id, ChannelInfo.id, TeamInfo.id, TenantInfo.id, ChannelDataSettings.selected_channel, Attachment.content_type, EntityBase.type.

MessageUpdateChannelData and MessageDeleteChannelData both inherit ChannelData, so they're covered without separate edits.

EntityBase.type is relaxed at the base rather than overridden on UnknownEntity: every concrete entity already overrides type with a Literal default, so UnknownEntity is the only class inheriting it raw. This also means an entity type introduced after this SDK version no longer drops the message.

Tests

New test_empty_inbound_objects.py covering each empty-object case, an unrecognized entity type, that populated values still parse, and that absent channelData is unchanged.

Validation

• 852 tests pass across packages/api + packages/apps 
• ruff format  / ruff check  clean
• pyright: zero net new errors

Notes

This is the defensive half. The empty object is a service-side wire-contract issue and has been raised with that team separately; this change means the SDK degrades gracefully regardless.

[Copilot]

Pull request overview

This PR addresses a regression where inbound Activities could be rejected entirely due to ValidationError when Microsoft Teams sends certain nested objects as empty {} (notably under channelData, plus empty attachments / entities). It relaxes several model fields so inbound parsing degrades gracefully instead of dropping the activity, and adds targeted unit tests to lock in the behavior (fixing #563).

Changes:

• Relaxed several channelData-related nested model fields to be optional so empty {} no longer fails validation (AppInfo.id, ChannelInfo.id, TeamInfo.id, TenantInfo.id, ChannelDataSettings.selected_channel).
• Relaxed Attachment.content_type and EntityBase.type to be optional so empty attachment/entity objects and forward-compatible entity types can parse.
• Added new unit tests covering the empty-object cases and a future/unknown entity type.

Reviewed changes

Copilot reviewed 8 out of 8 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
packages/api/tests/unit/test_empty_inbound_objects.py	Adds regression tests for empty nested inbound objects and unknown entity types.
packages/api/src/microsoft_teams/api/models/entity/entity_base.py	Makes base entity type optional to allow unknown/empty entities to parse.
packages/api/src/microsoft_teams/api/models/channel_data/tenant_info.py	Makes TenantInfo.id optional to tolerate empty tenant objects.
packages/api/src/microsoft_teams/api/models/channel_data/team_info.py	Makes TeamInfo.id optional to tolerate empty team objects.
packages/api/src/microsoft_teams/api/models/channel_data/settings.py	Makes selected_channel optional to tolerate empty settings objects.
packages/api/src/microsoft_teams/api/models/channel_data/channel_info.py	Makes ChannelInfo.id optional to tolerate empty channel objects.
packages/api/src/microsoft_teams/api/models/channel_data/app_info.py	Makes AppInfo.id optional to tolerate empty app objects.
packages/api/src/microsoft_teams/api/models/attachment/attachment.py	Makes Attachment.content_type optional to tolerate empty attachment objects.

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