Enable Custom Exception Provider with Durable Functions Java

[nytian]

Today when a Java activity fails, only the exception type and message reach the Durable extension. The TaskFailureDetails from the worker cannot carry user context like error codes or correlation IDs, so that data is dropped at the worker to host boundary. Users have no supported way to surface it in their error handling.

This PR adds an ActivityMiddleware that fixes this. When an activity throws, it runs a registered ExceptionPropertiesProvider and serializes the exception into structured TaskFailureDetails JSON, including error type, message, stack trace, nested causes, and custom properties. It runs worker side while the live Exception still exists, which is the only place this data is available before serialization.

Nested causes are emitted as innerFailure, bounded by MAX_INNER_FAILURE_DEPTH (10). Provider discovery uses cross class loader SPI lookup so it works from worker threads. When no provider is registered, the original exception is rethrown unchanged, so the change is additive. Also registers the middleware via SPI and adds the properties field to TaskFailureDetails. Adds ActivityMiddlewareTest, and the e2e test at durable extension repo accordingy

[Copilot]

Pull request overview

This PR adds Azure Functions activity middleware that enables opt-in structured exception properties (via ExceptionPropertiesProvider) to be surfaced as a TaskFailureDetails-shaped JSON payload when an activity fails, aligning behavior with Durable Task failure details handling.

Changes:

• Introduces ActivityMiddleware to reshape activity failures into TaskFailureDetails JSON when a provider returns custom properties, with SPI-based provider discovery across class loaders.
• Registers the new middleware via META-INF/services and adds unit tests (including cross-class-loader SPI discovery regression coverage).
• Updates protobuf source tracking and fixes a minor syntax typo in the proto file.

Reviewed changes

Copilot reviewed 7 out of 7 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
internal/durabletask-protobuf/protos/orchestrator_service.proto	Fixes a proto syntax typo (extra semicolon) in a deprecated field.
internal/durabletask-protobuf/PROTO_SOURCE_COMMIT_HASH	Updates the recorded upstream protobuf source commit hash.
azurefunctions/src/main/java/com/microsoft/durabletask/azurefunctions/internal/middleware/ActivityMiddleware.java	Adds new activity middleware to reshape failures into TaskFailureDetails JSON and discover providers via SPI.
azurefunctions/src/main/resources/META-INF/services/com.microsoft.azure.functions.internal.spi.middleware.Middleware	Registers ActivityMiddleware for Azure Functions SPI middleware discovery.
azurefunctions/src/test/java/com/microsoft/durabletask/azurefunctions/internal/middleware/ActivityMiddlewareTest.java	Adds unit coverage for reshaping behavior and SPI discovery across class loaders.
azurefunctions/src/test/java/com/microsoft/durabletask/azurefunctions/internal/middleware/TestExceptionPropertiesProvider.java	Adds a test-only provider for verifying SPI discovery behavior.
azurefunctions/build.gradle	Adds azure-functions-java-spi as a test dependency so middleware tests compile.

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[bachuv]

Does this match the depth configured in the other SDKs?

[nytian]

I remember .NET has a similar configuration,but the max depth value may be different. And for dotnet, it applies more broadly to all TaskFailedException scenarios, not just activity functions. Since this change only affects activity functions, I think a limit of 10 should be sufficient. It just helps ensure we don't end up recursing indefinitely.

[bachuv]

Should we also check inner exceptions for custom properties when the outer exception has none?

[nytian]

yeah Imissed that. We do support inner failures for at dotnet and js, let me update this part..