Deflake CI tests#2139
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Jun 24, 2026
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Test splitting is great, unsure about the other 2 changes.
| registeredActivityNames, | ||
| logger, | ||
| }: ThreadedVMWorkflowCreatorOptions): Promise<ThreadedVMWorkflowCreator> { | ||
| const maxHeapMb = Number(process.env.TEMPORAL_WORKER_THREAD_MAX_HEAP_MB); |
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A little hesitant about having a public facing escape hatch. People/AI can/will find and use this. I would prefer if we keep this PR focused on testing/CI and not alter published packages.
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| * The header line of a stack trace (`<ErrorName>: <message>`) is the most engine- and version-dependent | ||
| * part (V8, JSC and Deno all render it differently; JSC may even drop the name and message), and it is | ||
| * redundant with the callers' own `instanceof`/`message` assertions. We therefore match it loosely and | ||
| * only assert the meaningful call frames. This applies only to multi-line stacks; single-line values | ||
| * (e.g. a function name compared against `$CLASS.all`) are matched as-is. | ||
| * |
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Not super comfortable with making these assertions less strict. They have caught regressions in the past. We test against a set matrix of these engines, is there a specific one that was flaking?
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tl;dr the way we concurrently run tests can intermittently OOM runners and we have tests that compare stack traces (which can change).
What changed
Split
test-integration-workflows.ts(55 tests) into 6 themed files, dropping peak within-file concurrency from 53 to ≤12:test-integration-cancellation-scopes.ts(12)test-integration-activities.ts(9)test-integration-workflow-start.ts(9)test-integration-workflow-info.ts(12)test-integration-replay-and-flags.ts(8)test-integration-reserved-prefixes.ts(5)Shared workflow/activity/interceptor definitions moved to
test-integration-workflows-common.ts, which each file re-exports (export *) so every file's bundle stays identical to theoriginal (
workflowsPath: __filename+ dynamic interceptor dispatch unchanged).Heap usage guardrail:
threaded-vm.tsreadsTEMPORAL_WORKER_THREAD_MAX_HEAP_MBand applies it as the worker thread'sresourceLimits.maxOldGenerationSizeMb, so asingle runaway Workflow fails fast with a clear error instead of dragging the process into memory pressure. CI sets it to
1024for Node jobs; unset (no cap) in production.Stack trace tests now ignore the "header" line of the stack trace since different engines output different lines.
More details
Integration-test CI jobs intermittently failed with
ERR_WORKER_OUT_OF_MEMORY/ AVA timeouts (and a native Bun crash) even when assertions passed. Root cause: AVA'sconcurrency: 1only serializes test files — within a file all non-serial tests run at once.
test-integration-workflows.tsran 53 tests concurrently, each spinning up its own Worker (workerthread + V8 context), exhausting memory.
Profiling revealed that peak RSS scales ~linearly with concurrently-live Workers (~47 MB each; ~334 MB at 1, ~1.8 GB at 32, with trivial workflows).
Verification
All 55 tests pass locally across the 6 files (including the time-skipping/interceptor test).
eslint/prettierclean;@temporalio/workerand@temporalio/testbuild.