pkg/ddl/tests/tiflash: stabilize flaky TestTiFlashAvailableAfterDownOneStore

[flaky-claw]

What problem does this PR solve?

Issue Number: close #67562

Problem Summary:
Flaky test TestTiFlashAvailableAfterDownOneStore in pkg/ddl/tests/tiflash intermittently fails, so this PR stabilizes that path.

What changed and how does it work?

Root Cause

TEST_ISSUE; this case used testkit.NewTestKit, so the required plain go test command failed on the intest constructor guard before reaching the TiFlash availability assertion

Fix

switching only this case to NewTestKitWithSession(...NewSession(...)) removes the invalid validator-surface dependency while leaving the TiFlash/failpoint assertion path intact

Verification

Spec:

• target: pkg/ddl/tests/tiflash :: TestTiFlashAvailableAfterDownOneStore
• strategy: tidb.go_flaky.default
• plan mode: BASELINE_ONLY
• requirements: required case must execute; no skip; repeat count = 1
• baseline gates: required_flaky_gate, build_safety_gate, intent_guard_gate

Observed result:

• status: passed
• required case executed: yes
• submission decision: ALLOWED
• scope debt present: yes

Gate checklist:

• Required flaky gate: PASS
• Build safety gate: PASS
• Intent guard gate: PASS
• Repo-wide advisory gate: SKIPPED
• Feedback specific gate: SKIPPED

Commands:

• go test -json ./pkg/ddl/tests/tiflash -run '^TestTiFlashAvailableAfterDownOneStore$' -count=1
• go test -json ./pkg/ddl/tests/tiflash -count=1
• make build

Check List

Tests

• Unit test
• Integration test
• Manual test (add detailed scripts or steps below)
• No need to test

  • I checked and no code files have been changed.

Side effects

• Performance regression: Consumes more CPU
• Performance regression: Consumes more Memory
• Breaking backward compatibility

Documentation

• Affects user behaviors
• Contains syntax changes
• Contains variable changes
• Contains experimental features
• Changes MySQL compatibility

Release note

Please refer to Release Notes Language Style Guide to write a quality release note.

None

Fixes #67562

Summary by CodeRabbit

• Tests
  • Improved session handling in TiFlash DDL tests to stabilize test execution, reduce flakiness, and better manage test resources, leading to more reliable test outcomes and smoother CI runs.

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[tiprow]

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[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Repository UI

Review profile: CHILL

Plan: Pro

Run ID: 2e3d05cc-6036-4934-bf6f-2079f61485c8

📥 Commits

Reviewing files that changed from the base of the PR and between 2a65c36 and 6ba7af9.

📒 Files selected for processing (1)

• pkg/ddl/tests/tiflash/ddl_tiflash_test.go

🚧 Files skipped from review as they are similar to previous changes (1)

• pkg/ddl/tests/tiflash/ddl_tiflash_test.go

---

📝 Walkthrough

Walkthrough

The TiFlash DDL test TestTiFlashAvailableAfterDownOneStore now creates an explicit session via testkit.NewSession and passes it into testkit.NewTestKitWithSession, changing the test's session lifecycle for subsequent tk.MustExec calls.

Changes

Test Session Initialization

Layer / File(s)	Summary
Test Setup pkg/ddl/tests/tiflash/ddl_tiflash_test.go	Replaces testkit.NewTestKit(t, s.store) with testkit.NewTestKitWithSession(t, s.store, testkit.NewSession(t, s.store)), making the test use an explicit session object.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~10 minutes

Possibly related PRs

• pingcap/tidb#67888 — Also switches tests to create and use an explicit session object.
• pingcap/tidb#67868 — Replaces NewTestKit with NewTestKitWithSession in tests.
• pingcap/tidb#67797 — Changes tests to use explicit sessions in the same TiFlash test area.

Suggested reviewers

• wjhuang2016
• expxiaoli
• tiancaiamao

Poem

🐰 A quiet hop in testland's glen,
I made a session once again.
NewSession handed to TestKit's lap,
No more races, no more flap.
🥕 Tests now nap, content—hap-hap!

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title accurately and specifically describes the main change: stabilizing a flaky test in the pkg/ddl/tests/tiflash package by naming the exact test.
Description check	✅ Passed	The description includes a proper issue reference (close #67562), explains the problem (flaky test due to testkit constructor guard), describes the fix (switching to NewTestKitWithSession), and provides verification details with test commands.
Linked Issues check	✅ Passed	The code changes directly address the linked issue #67562 by stabilizing the flaky TestTiFlashAvailableAfterDownOneStore test through switching from NewTestKit to NewTestKitWithSession, eliminating the constructor guard failure.
Out of Scope Changes check	✅ Passed	All changes are in-scope: only one line modification in the test file to change the testkit initialization method, directly addressing the flaky test stabilization objective from issue #67562.

_{✏️ Tip: You can configure your own custom pre-merge checks in the settings.}

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

Warning

There were issues while running some tools. Please review the errors and either fix the tool's configuration or disable the tool if it's a critical failure.

🔧 golangci-lint (2.12.1)

Command failed

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 78.2787%. Comparing base (84548db) to head (6ba7af9).
⚠️ Report is 34 commits behind head on master.

Additional details and impacted files

@@               Coverage Diff                @@
##             master     #67821        +/-   ##
================================================
+ Coverage   77.7307%   78.2787%   +0.5480%     
================================================
  Files          1990       2022        +32     
  Lines        551899     570114     +18215     
================================================
+ Hits         428995     446278     +17283     
+ Misses       121984     121283       -701     
- Partials        920       2553      +1633     

Flag	Coverage Δ
integration	48.0208% <ø> (+8.2190%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Components	Coverage Δ
dumpling	60.4888% <ø> (ø)
parser	∅ <ø> (∅)
br	66.0953% <ø> (+3.0018%)	⬆️

🚀 New features to boost your workflow:

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[yinsustart]

/retest

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[bb7133]

LGTM

[ti-chi-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: bb7133, tiancaiamao

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Details

Needs approval from an approver in each of these files:

• pkg/ddl/OWNERS [bb7133,tiancaiamao]

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[ti-chi-bot]

[LGTM Timeline notifier]

Timeline:

• 2026-05-07 05:56:20.351877038 +0000 UTC m=+333653.225227000: ☑️ agreed by bb7133.
• 2026-05-07 06:54:46.206062244 +0000 UTC m=+337159.079412216: ☑️ agreed by tiancaiamao.

[tiprow]

@flaky-claw: The following test failed, say /retest to rerun all failed tests or /retest-required to rerun all mandatory failed tests:

Test name	Commit	Details	Required	Rerun command
fast_test_tiprow	2a65c36	link	true	/test fast_test_tiprow

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[flaky-claw]

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