fix(pyamber): allow worker state to transit READY -> COMPLETED#5214
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mengw15 merged 2 commits intoMay 26, 2026
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A Python UDF worker whose upstream produces zero tuples receives an
EndChannel marker before any data, so it never visits RUNNING. When
`_process_end_channel` then calls `complete()`, the state machine in
`Context` rejected the transition because READY's allowed targets were
`{PAUSED, RUNNING}`, and the worker thread died with
`InvalidTransitionException: Cannot transit from READY to COMPLETED`.
The downstream operator stayed in READY and the workflow hung.
The Scala-side WorkerStateManager already includes COMPLETED in
READY's allowed targets; the Python state graph had drifted out of
sync. Add `WorkerState.COMPLETED` to the READY set so the two stay
aligned and zero-input workers can complete cleanly.
Lift the state-transition graph out of `Context.__init__` into a
module-level `WORKER_STATE_TRANSITIONS` constant so the test fixture
can import it (single source of truth) and so the graph is built once
per process instead of once per Context.
Closes apache#5197.
Yicong-Huang
changed the title
Contributor
|
let's call it pyamber, because we have other components like pybuilder as well. calling it python is a bit too general. |
Contributor
|
also it will be ideal to simplify pr description. it is a bit too detailed. Especially on the "How was this PR tested?" part |
Codecov Report✅ All modified and coverable lines are covered by tests. Additional details and impacted files@@ Coverage Diff @@
## main #5214 +/- ##
=========================================
Coverage 48.33% 48.33%
Complexity 2342 2342
=========================================
Files 1042 1042
Lines 39973 39974 +1
Branches 4251 4251
=========================================
+ Hits 19322 19323 +1
Misses 19507 19507
Partials 1144 1144
*This pull request uses carry forward flags. Click here to find out more. ☔ View full report in Codecov by Sentry. 🚀 New features to boost your workflow:
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What changes were proposed in this PR?
A Python UDF worker whose upstream produces zero tuples receives an
EndChannelmarker before any data, so it never visitsRUNNING. When_process_end_channelcallscomplete(), the state machine inContextrejectedREADY → COMPLETEDand the worker died withInvalidTransitionException, leaving the downstream operator stuck and the workflow hung.The Scala-side
WorkerStateManageralready listsCOMPLETEDinREADY's allowed targets — this is a Python ↔ Scala parity drift. AddWorkerState.COMPLETEDto the PythonREADYset.Also lift the state-transition graph out of
Context.__init__into a module-levelWORKER_STATE_TRANSITIONSconstant so the test fixture can import it (single source of truth — the previous fixture independently duplicated the graph, which is what masked the parity gap from existing tests).Any related issues, documentation, discussions?
Closes #5197.
How was this PR tested?
Added a regression test in
test_state_manager.pycoveringREADY → COMPLETED. Also manually verified the issue's reproducer workflow now completes; previously hung with the worker stuck inREADY.Was this PR authored or co-authored using generative AI tooling?
Generated-by: Claude Code (claude-opus-4-7)