*: update client-go to latest master

[wfxr]

What problem does this PR solve?

Issue Number: ref #71489

Problem Summary:

TiDB master still pins client-go 5f38569c8cc0, which predates the client-go Go 1.25.14 upgrade. The current client-go master head is b9fc0b7719d3.

What changed and how does it work?

Update github.com/tikv/client-go/v2 to v2.0.8-0.20260923121349-b9fc0b7719d3 and regenerate its Go checksums and Bazel dependency entry. This picks up the Go 1.25.14 upgrade, transaction fixes, and the later RU v2 cleanup. TiDB already uses Go 1.25.14.

This overlaps #71587, which updates client-go only through 1fd036c3e010 for undetermined commit handling. This PR targets the current client-go master head for the separate version-sync purpose. If #71587 merges first, this PR should be rebased so that only the remaining update is shown.

Check List

Tests

• Unit test
  • GOWORK=off GOTOOLCHAIN=go1.25.14 ./tools/check/failpoint-go-test.sh pkg/store/driver -run '^TestTxnGet$' -count=1 -tags=intest,deadlock
• Integration test
• Manual test (add detailed scripts or steps below)
  • GOTOOLCHAIN=go1.25.14 make bazel_prepare
  • GOWORK=off GOTOOLCHAIN=go1.25.14 go mod verify
  • GOWORK=off GOTOOLCHAIN=go1.25.14 go mod tidy
  • git show --format= --check HEAD
  • The repository-wide check commit hook reformatted unrelated br/pkg/restore/ingestrec/foreign_key.go and blocked the commit; that hook output was restored, and the go-mod-tidy hook passed. Full suite and integration tests were not run locally.
• 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

Summary by CodeRabbit

• Chores
  • Updated the underlying TiKV client component to a newer version. No user-facing changes are noted.

[coderabbitai]

Navigate logical layers of code changes, visualize relationships, and explore their blast radius.

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ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Repository UI

Review profile: CHILL

Plan: Advanced

Run ID: aa806d28-ef78-42bf-b64e-2fc3c2dce1db

📥 Commits

Reviewing files that changed from the base of the PR and between 4f27dad and d0133fd.

⛔ Files ignored due to path filters (1)

• go.sum is excluded by !**/*.sum

📒 Files selected for processing (2)

• DEPS.bzl
• go.mod

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📝 Walkthrough

Walkthrough

The github.com/tikv/client-go/v2 dependency is updated to the 20260923 revision in go.mod and DEPS.bzl. The Bazel checksum is also updated.

Changes

TiKV client-go dependency update

Layer / File(s)	Summary
Update dependency declarations go.mod, DEPS.bzl	go.mod and DEPS.bzl now reference the 20260923 revision of github.com/tikv/client-go/v2. DEPS.bzl also contains the updated checksum.

Priority: ⬇️ Low

Estimated code review effort: 1 (Trivial) | ~5 minutes

Change: Other

Suggested reviewers: lcwangchao

Merge Risk: ⚪ Minimal · up to d0133

No actionable issue is established for this dependency update. It is mergeable after normal checks.

🚥 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%. Docstring coverage is scoped to functions touched by this diff. Analyzed 1 functions across 1 files. (1 skipped: 1 …	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Title check	✅ Passed	The title clearly identifies the main change: updating client-go to the current master revision. It is concise and follows the repository's accepted *: what's changed format.
Description check	✅ Passed	The description is complete and follows the repository template. It includes the issue reference, problem summary, implementation details, test and manual-check results, side-effect and documentation …

Full details: Docstring Coverage

Explanation

Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 1 functions across 1 files. (1 skipped: 1 unsupported.)

• Fix all pre-merge checks with AI

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create a new PR

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_{A rabbit checks the version string,
And sees the newer pin take wing.
The checksum hops to match the date,
Both files now show the same update.
The rabbit rests beside the gate.}

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[ti-chi-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: cfzjywxk, lcwangchao

The full list of commands accepted by this bot can be found here.

The pull request process is described here

Details

Needs approval from an approver in each of these files:

• OWNERS [cfzjywxk,lcwangchao]

Approvers can indicate their approval by writing /approve in a comment
Approvers can cancel approval by writing /approve cancel in a comment

[ti-chi-bot]

[LGTM Timeline notifier]

Timeline:

• 2026-09-24 07:54:11.619117848 +0000 UTC m=+264176.844338945: ☑️ agreed by lcwangchao.
• 2026-09-24 07:55:30.40211096 +0000 UTC m=+264255.627332087: ☑️ agreed by cfzjywxk.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 72.0833%. Comparing base (4f27dad) to head (d0133fd).
⚠️ Report is 4 commits behind head on master.

Additional details and impacted files

@@               Coverage Diff                @@
##             master     #71608        +/-   ##
================================================
- Coverage   76.2996%   72.0833%   -4.2164%     
================================================
  Files          2041       2110        +69     
  Lines        554520     604156     +49636     
================================================
+ Hits         423097     435496     +12399     
- Misses       130523     166685     +36162     
- Partials        900       1975      +1075     

Flag	Coverage Δ
integration	41.2852% <ø> (+1.6135%)	⬆️

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

Components	Coverage Δ
dumpling	58.8395% <ø> (ø)
parser	∅ <ø> (∅)
br	46.5727% <ø> (-16.1371%)	⬇️

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[cfzjywxk]

/retest

[wfxr]

/retest

[wfxr]

/retest

[wfxr]

/retest

[ti-chi-bot]

In response to a cherrypick label: new pull request could not be created: failed to create pull request against pingcap/tidb#release-nextgen-202609 from head ti-chi-bot:cherry-pick-71608-to-release-nextgen-202609: status code 422 not one of [201], body: {"message":"Validation Failed","errors":[{"resource":"PullRequest","code":"custom","message":"No commits between pingcap:release-nextgen-202609 and ti-chi-bot:cherry-pick-71608-to-release-nextgen-202609"}],"documentation_url":"https://docs.github.com/rest/pulls/pulls#create-a-pull-request","status":"422"}