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fix(sdk): don't NPE in CallbackFailedException when the callback has no error - #774
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zhongkechen merged 2 commits intoOct 5, 2026
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…no error SendDurableExecutionCallbackFailure accepts a request without an Error, so a FAILED callback operation can arrive with no CallbackDetails.Error. buildMessage dereferenced the error unconditionally, so get() threw NullPointerException instead of CallbackFailedException. Fall back to "Callback failed", matching the JS SDK. Fixes aws#773
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Thanks for fixing this and adding a regression test! The null guard correctly handles a missing callback error while preserving the existing behavior when an error is present. I checked both callback failure paths and ran the 27 related exception, callback-operation, and child-context tests locally; all passed.
Parallel can finish after the second failure while a successful branch is still running. That branch may skip its terminal checkpoint, so a fixed total history size depends on scheduling. Assert the failure threshold, branch outcomes, and the parallel operation's own checkpoint events instead. Verify that replay preserves both the result and history in FLAT and NESTED modes. Validation: Java 25 SDK, testing utilities, and local integration suites (1647 tests); Java 17 parallel and child-context tests; Spotless check. A controlled late-branch probe also verified stable results and history on replay.
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Issue Link, if available
Fixes #773
Description
SendDurableExecutionCallbackFailureaccepts a request with noError, so aCALLBACKoperation can come backFAILEDwith noCallbackDetails.Error.CallbackFailedException.buildMessagecallederror.errorType()without a null check.CallbackOperation.get()(andChildContextOperation.handleWaitForCallbackFailure) then threwNullPointerExceptioninstead ofCallbackFailedException, and acatch (CallbackFailedException e)block never saw it.The fix is a null guard in
buildMessagethat falls back to"Callback failed", the same message the JS SDK uses.getErrorObject()staysnull, whichDurableOperationExceptionalready allows. Both call sites build the exception through this constructor, so they are both covered.Demo/Screenshots
N/A
Checklist
Testing
Unit Tests
Yes.
CallbackExceptionTest.testCallbackFailedExceptionWithoutErrorbuilds a callback operation with no error and checks the callback id, the operation, anullerror object, and the message"Callback failed".NullPointerException: Cannot invoke "ErrorObject.errorType()" because "error" is nullatCallbackFailedException.buildMessage.mvn -pl sdk -am testpasses, 1203 tests, 0 failures.mvn spotless:checkis clean.Integration Tests
No. This is an isolated fix inside the exception's constructor, and the unit test covers it.
Examples
N/A