feat(durabletask): implement timer origin and backwards-compatible optional timers

[javier-aliaga]

Description

Annotate every CreateTimerAction the SDK emits with the new origin oneof from durabletask-protobuf (CreateTimer / ExternalEvent / ActivityRetry / ChildWorkflowRetry), and emit a synthetic "optional" timer for waitForExternalEvent calls with a negative (indefinite) timeout.

• CreateTimer: TimerOriginCreateTimer on every user-facing timer.
• waitForExternalEvent: TimerOriginExternalEvent{name} on timeout timers; indefinite timeouts emit a single optional timer with fireAt = sentinel 9999-12-31T23:59:59.999999999Z so the backend has a record of the wait.
• Activity retry delays: TimerOriginActivityRetry carrying a stable taskExecutionId shared with the ScheduleTaskAction.
• Child-workflow retry delays: TimerOriginChildWorkflowRetry carrying the first child's instanceId.

Add dropOptionalExternalEventTimerAt(atId) and wire it into handleTaskScheduled, handleSubOrchestrationCreated, and handleTimerCreated so pre-upgrade histories (which lack the synthetic timer emitted by indefinite waitForExternalEvent calls) replay without non-determinism errors. Mirrors the shape of durabletask-go's task/orchestrator.go.

Includes 13 unit tests covering origin assignment across all four call sites and the optional-timer replay-compatibility machinery.

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: #1729

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]

Pull request overview

Note

Copilot was unable to run its full agentic suite in this review.

Implements timer-origin annotation across all SDK-emitted timers and adds a backwards-compatible “optional” (synthetic) timer for indefinite waitForExternalEvent calls to improve backend observability and replay compatibility (fixes #1729).

Changes:

• Annotate CreateTimerAction with the new protobuf origin oneof for user timers, external-event timeouts, activity retries, and child-workflow retries.
• Emit a synthetic sentinel timer for indefinite external-event waits and add replay-compat “drop-and-shift” logic for pre-upgrade histories.
• Add a comprehensive JUnit test suite covering origin assignment and replay compatibility scenarios.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 5 comments.

File	Description
durabletask-client/src/main/java/io/dapr/durabletask/TaskOrchestrationExecutor.java	Adds origin setters for timers, synthetic optional external-event timer emission, and replay-compat drop/shift handling.
durabletask-client/src/test/java/io/dapr/durabletask/TimerOriginTest.java	Adds unit tests validating origin assignment and optional-timer replay compatibility behavior.

Comments suppressed due to low confidence (1)

durabletask-client/src/test/java/io/dapr/durabletask/TimerOriginTest.java:1

• Several pre-patch replay tests hardcode taskExecutionId values (e.g., exec-A, exec-B) even though those IDs are not the focus of the test and may become validated more strictly in the future. To make these tests more robust, consider omitting the field (pass null to taskScheduled) or discover the emitted taskExecutionId in a phase-1 run (as done in Tests 3/4) when the ID matters.

/*

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.

[siri-varma]

LGTM

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 76.76%. Comparing base (4ec9b89) to head (f91fb27).
⚠️ Report is 1 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff            @@
##             master    #1733   +/-   ##
=========================================
  Coverage     76.76%   76.76%           
  Complexity     2260     2260           
=========================================
  Files           241      241           
  Lines          7066     7066           
  Branches        740      740           
=========================================
  Hits           5424     5424           
  Misses         1279     1279           
  Partials        363      363           

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.