.NET: Fix function approvals persistance with PerServiceCallChatHistoryPersistingChatClient

[scrodde]

Motivation and Context

PerServiceCallChatHistoryPersistingChatClient.GetStreamingResponseAsync snapshotted each update via update.Clone() (PR #5310, 1.4.0). Clone() is shallow: it shares the Contents list reference. FunctionInvokingChatClient rewrites FunctionCallContent → ToolApprovalRequestContent for ApprovalRequiredAIFunction tools by reassigning update.Contents to a new list, so the snapshot retained the pre-rewrite list and the ChatHistoryProvider received raw FunctionCallContent instead of ToolApprovalRequestContent.

Description

Revert to capturing the same reference so the so the persisted history sees FIC's rewrite

Contribution Checklist

• The code builds clean without any errors or warnings
• The PR follows the Contribution Guidelines
• All unit tests pass, and I have added new tests where possible
• Is this a breaking change? If yes, add "[BREAKING]" prefix to the title of the PR.

[scrodde]

Agreement

@microsoft-github-policy-service agree company="switchvisual"

[Copilot]

Pull request overview

Fixes a regression in the .NET chat history persistence pipeline where per-service-call streaming persistence could miss FunctionInvokingChatClient’s rewrite from FunctionCallContent to ToolApprovalRequestContent for ApprovalRequiredAIFunction tools.

Changes:

• Update PerServiceCallChatHistoryPersistingChatClient.GetStreamingResponseAsync to retain the original ChatResponseUpdate reference (instead of a shallow Clone()), so later Contents rewrites are reflected in persisted history.
• Add a unit test that reproduces the 1.4.0 regression and asserts that persisted history includes the approval-rewritten content.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
dotnet/src/Microsoft.Agents.AI/ChatClient/PerServiceCallChatHistoryPersistingChatClient.cs	Stops cloning streaming updates so persisted aggregation observes Contents rewrites performed by upstream middleware.
dotnet/tests/Microsoft.Agents.AI.UnitTests/ChatClient/PerServiceCallChatHistoryPersistingChatClientTests.cs	Adds a regression test ensuring approval-required function calls persist rewritten ToolApprovalRequestContent.

[scrodde]

@moonbox3 stuck at 1.3.0 due to this error.

[moonbox3]

Adding @westey-m, @SergeyMenshykh, and @rogerbarreto to help.

[westey-m]

@scrodde, the clone introduction was on purpose to avoid storing the FunctionInvokingChatClient modified contents, since the modifications was resulting in failures, where follow up requests after a tool call failed due to mismatched FunctionCallContent and FunctionResultContent.

Can you explain in more detail what problem you are trying to solve?