[SDK Sentinel] Stabilize immediate schedule trigger test

[sdk-sentinel-bot]

Caution

This PR contains untrusted AI-generated code. Do not approve or run CI until a maintainer has reviewed the diff. SDK Sentinel verified that GitHub Actions remained approval-gated with zero executable jobs when this PR was opened.

Summary

• CI evidence: failed CI job · workflow run · first known failure

Stabilize the Cloud integration test after the [first captured Cloud failure](https://github.com/temporalio/sdk-python/actions/runs/33407614934/job/99538982979) observed zero actions immediately after creating a schedule with an immediate trigger. The bounded snapshot contains no earlier equivalent passing Cloud run.

Root cause

create_schedule can return before the triggered action is visible through describe in Cloud's eventually consistent schedule state. The test assumed synchronous visibility after it became Cloud-eligible in the [Cloud suite expansion](f6594f1).

Fix

Poll describe with the repository's existing eventual-consistency helper until one action is visible, then reuse that successful description for the workflow assertions.

Validation

The pre-change local test passed once, so natural reproduction did not occur. The candidate passed 10 focused stress repetitions and the canonical repository validator. The actual Cloud path remains untested locally and requires the cloud-test envconfig CI job.

Validation status: ci-validation-required

• Flake confidence: high
• Fix confidence: high
• Value: medium
• Patch scope: standard — 1 changed file; 847 B
• Local reproduction: not-reproduced — The pre-change test passed once against the local server; the external Cloud environment was unavailable under the investigation network boundary.
• Regression coverage: pass-after-only — The adjusted test passed 10 focused post-change stress repetitions; no deterministic pre-change failure was available locally.
• Unchanged baseline (Poe lint, bridge lint, and editable build) — passed
• Independent candidate (Poe lint, bridge lint, and editable build) — passed

Investigator-run checks

• poe test -s -k test_schedule_trigger_immediately — passed; 1 attempt(s). Pre-change local-server run passed; the Cloud timing window was not reproduced.
• poe test -s -k test_schedule_trigger_immediately --flake-finder --flake-runs=10 — passed; 10 attempt(s). Post-change local-server stress run passed all 10 repetitions.
• .ci-flake-runtime/input/validate.sh — failed; 1 attempt(s). Python checks passed, but the investigation HOME pointed rustup at an empty toolchain cache.
• RUSTUP_HOME=/home/runner/.rustup CARGO_HOME=/home/runner/work/sdk-sentinel/sdk-sentinel/target/.ci-flake-runtime/cache/cargo .ci-flake-runtime/input/validate.sh — passed; 1 attempt(s). The unchanged canonical validator passed using the preloaded offline Rust toolchain and Cargo cache.

Required target CI

• Continuous Integration / cloud-test using the envconfig workflow environment on Linux

Residual risks

• The candidate was not exercised against Temporal Cloud locally.
• Schedule visibility taking longer than the helper's 10-second timeout would still fail.

Automation provenance

• Investigator workflow
• Base SHA: b6ee53cf748cfc98d9e32eee2d136ca8abb9a6ad

If this finding should not be fixed, apply the sdk-sentinel:false-positive label and close the PR. Sentinel will suppress the finding until its affected source changes.

SDK Sentinel recurrence history

• Unique failed CI run attempts: 1
• First occurrence: 2026-08-31 15:28 UTC
• Latest occurrence: 2026-08-31 15:28 UTC
• Recent occurrences:
  • 2026-08-31 15:28 UTC — failed CI job