Workflow: cross-app client operations

[JoshVanL]

Adds an optional app ID to every client-level workflow operation on DaprWorkflowClient: scheduleNewWorkflow, getWorkflowState, waitForWorkflowStart, waitForWorkflowCompletion, raiseEvent, suspendWorkflow, resumeWorkflow, terminateWorkflow and purgeWorkflow. When set, the operation targets a workflow instance owned by another app in the same namespace, and the target app's WorkflowAccessPolicy decides whether it is permitted. The existing signatures stay and delegate with a null app ID, so local behaviour is unchanged.

NewWorkflowOptions gains setAppId for scheduling a workflow on another app. DurableTaskClient mirrors the same overloads, and DurableTaskGrpcClient carries the value as a TaskRouter on each request via the new buildTaskRouter helper. An older runtime ignores the field and applies the operation to the caller's own app.

Description

Please explain the changes you've made

Issue reference

We strive to have all PR being opened based on an issue, where the problem or feature have been discussed prior to implementation.

Please reference the issue this PR will close: #[issue number]

Checklist

Please make sure you've completed the relevant tasks for this PR, out of the following list:

• Code compiles correctly
• Created/updated tests
• Extended the documentation

[Copilot]

🟡 Changes recommended

The new abstract methods break external implementations, and empty app IDs are routed inconsistently.

Once you've addressed the issues Copilot identified, you can request another Copilot review.

Pull request overview

Adds cross-app routing to workflow client operations while retaining local-operation overloads.

Changes:

• Adds app-ID-aware workflow and durable-task APIs.
• Attaches TaskRouter metadata to gRPC requests.
• Adds unit and multi-app integration coverage.

File summaries

File	Description
DaprWorkflowClientTest.java	Tests app-ID forwarding.
NewWorkflowOptions.java	Adds target app ID configuration.
DaprWorkflowClient.java	Adds cross-app workflow operations.
WorkflowsMultiAppCrossAppOperationsIT.java	Tests remote workflow lifecycle operations.
CrossAppEventWorkflow.java	Provides the integration-test workflow.
CrossAppEventWorker.java	Hosts the integration-test workflow.
ContainerConstants.java	Adds the edge runtime image tag.
DurableTaskGrpcClientRoutingTest.java	Verifies request router metadata.
DurableTaskGrpcClient.java	Adds routers to gRPC requests.
DurableTaskClient.java	Adds app-ID overloads and compatibility delegates.

Review details

• Files reviewed: 10/10 changed files
• Comments generated: 3
• Review effort level: Balanced

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[Copilot]

🟡 Changes recommended

The integration test uses a mutable runtime image, and two public API contracts need correction.

Once you've addressed the issues Copilot identified, you can request another Copilot review.

Review details

Suppressed comments (2)

Previously missed (2) — in code that hasn't changed since the last review.

sdk-tests/src/test/java/io/dapr/it/testcontainers/ContainerConstants.java:9

• This mutable edge tag makes the integration suite depend on whatever dapr/dapr master produced most recently. A later image change can break CI—or become incompatible with the separately pinned 1.18 placement and scheduler images—without any SDK change. Please pin the tested edge build to an immutable tag or digest and update it deliberately.
  sdk-workflows/src/main/java/io/dapr/workflows/client/NewWorkflowOptions.java:165
• Empty app IDs are also treated as local routing, but this return contract implies that only null represents the local app. After setAppId(""), getAppId() returns an empty string while routing locally, so callers could misinterpret the result.

• Files reviewed: 10/10 changed files
• Comments generated: 1
• Review effort level: Balanced

[Copilot]

🔵 Needs a closer look

The public API and routing changes depend on unreleased runtime behavior validated through a mutable, non-gating edge-image job.

Review details

• Files reviewed: 12/12 changed files
• Comments generated: 0 new
• Review effort level: Balanced

[Copilot]

🟢 Approval recommended

Cross-app routing is consistently implemented and covered by focused unit and integration tests.

Review details

• Files reviewed: 12/12 changed files
• Comments generated: 0 new
• Review effort level: Balanced

[codecov]

Codecov Report

❌ Patch coverage is 78.26087% with 5 lines in your changes missing coverage. Please review.
✅ Project coverage is 78.17%. Comparing base (9a7be01) to head (7e2b845).

Files with missing lines	Patch %	Lines
...a/io/dapr/workflows/client/DaprWorkflowClient.java	75.00%	1 Missing and 4 partials ⚠️

Additional details and impacted files

@@            Coverage Diff            @@
##             master    #1806   +/-   ##
=========================================
  Coverage     78.17%   78.17%           
- Complexity     2427     2438   +11     
=========================================
  Files           248      248           
  Lines          7438     7461   +23     
  Branches        774      780    +6     
=========================================
+ Hits           5815     5833   +18     
- Misses         1267     1268    +1     
- Partials        356      360    +4     

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