*: bump client-go to tidb-8.5 head

[wfxr]

What problem does this PR solve?

Issue Number: ref #69335

Problem Summary:

The tidb-8.5 branch of client-go has upgraded its Go version to 1.25.12. TiDB release-8.5 needs to consume that merged client-go commit so the two repositories use aligned toolchain requirements.

What changed and how does it work?

• Bump github.com/tikv/client-go/v2 from a2b634d170d9 to c3b50791b9fb (v2.0.8-0.20260803075849-c3b50791b9fb).
• Refresh go.sum and the Bazel dependency metadata in DEPS.bzl.
• Regenerate affected BUILD.bazel files with make bazel_prepare.

Check List

Tests

• Unit test
  • GOTOOLCHAIN=go1.25.12 go test -count=1 -p=1 -tags=intest ./pkg/store/...
  • GOTOOLCHAIN=go1.25.12 go mod verify
  • make check-bazel-prepare
• 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

None

Summary by CodeRabbit

• Chores

  • Updated underlying system components to incorporate the latest maintenance improvements.
  • Refined build configuration to support smoother development and release workflows.

• Tests

  • Improved test distribution for more efficient execution.
  • Enhanced test configuration and coverage for server-related behavior.
  • Added safeguards for tests that may occasionally experience timing-related instability.

[coderabbitai]

📝 Walkthrough

Walkthrough

The change updates github.com/tikv/client-go/v2 to a newer revision in Go and Bazel metadata. It also adjusts sharding, dependencies, timeout, and flaky status for selected Bazel tests.

Changes

Dependency and test configuration

Layer / File(s)	Summary
Update client-go dependency DEPS.bzl, go.mod	Both dependency declarations now use revision v2.0.8-0.20260803075849-c3b50791b9fb. DEPS.bzl also uses the matching checksum.
Adjust Bazel test targets pkg/disttask/importinto/BUILD.bazel, pkg/server/BUILD.bazel, pkg/util/sqlkiller/BUILD.bazel	importinto_test uses 19 shards. server_test adds the server error library. sqlkiller_test uses a short timeout and is marked flaky.

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

Possibly related PRs

• pingcap/tidb#70301: Updates the same github.com/tikv/client-go/v2 version and checksum.
• pingcap/tidb#70244: Updates dependency pins in DEPS.bzl and go.mod.

Suggested reviewers: ti-chi-bot, djshow832, yangkeao

Poem

A rabbit checked the version pin,
And found a newer client within.
More test shards split the load,
Server paths gained the code they showed,
Short tests now hop through flaky clover—
Clean builds wait just one hop over.

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
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 for the tidb-8.5 branch.
Description check	✅ Passed	The description includes the issue, problem, changes, tests, side effects, documentation status, and release note.

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

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[ti-chi-bot]

[LGTM Timeline notifier]

Timeline:

• 2026-08-03 08:44:34.857562396 +0000 UTC m=+2431260.893657452: ☑️ agreed by cfzjywxk.
• 2026-08-03 08:48:36.320220898 +0000 UTC m=+2431502.356315954: ☑️ agreed by ekexium.

[ti-chi-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: cfzjywxk, D3Hunter, ekexium

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 [D3Hunter,cfzjywxk,ekexium]
• pkg/disttask/OWNERS [D3Hunter]

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

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
⚠️ Please upload report for BASE (release-8.5@4f4bc88). Learn more about missing BASE report.

Additional details and impacted files

@@               Coverage Diff                @@
##             release-8.5     #70303   +/-   ##
================================================
  Coverage               ?   55.4410%           
================================================
  Files                  ?       1849           
  Lines                  ?     670985           
  Branches               ?          0           
================================================
  Hits                   ?     372001           
  Misses                 ?     271223           
  Partials               ?      27761           

Flag	Coverage Δ
integration	38.6415% <ø> (?)
unit	65.2130% <ø> (?)

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

Components	Coverage Δ
dumpling	55.3108% <0.0000%> (?)
parser	∅ <0.0000%> (?)
br	56.1521% <0.0000%> (?)

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.

[wfxr]

/retest