pkg/util/hack: split map ABI for go1.25 and go1.26 by hawkingrei · Pull Request #66254 · pingcap/tidb

hawkingrei · 2026-02-13T09:44:25Z

What problem does this PR solve?

Issue Number: close #65761

Problem Summary:
pkg/util/hack/map_abi.go is hardcoded to the Go 1.25 swiss-map ABI and panics under Go 1.26. We need version-specific ABI definitions to keep the memory-aware map implementation working across both toolchains.

What changed and how does it work?

Added Go-version split for map ABI implementation in pkg/util/hack:
- map_abi.go is now guarded by //go:build go1.25 && !go1.26
- New file map_abi_go126.go is guarded by //go:build go1.26 && !go1.27
Kept the 1.25 implementation unchanged for the existing ABI path.
Added the 1.26 counterpart with the same structure and logic shape, while switching the runtime version guard to go1.26.
Updated pkg/util/hack/BUILD.bazel to include the new source file.

Check List

Tests

Unit test

test it with go1.26.0

#66256

Integration test
Manual test (add detailed scripts or steps below)

It can compile with go1.26

No need to test
- I checked and no code files have been changed.
- This change only introduces Go-version build-tag split and keeps per-version runtime logic equivalent.

Side effects

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

Documentation

Release note

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

None

pantheon-ai · 2026-02-13T09:44:29Z

✅ Review completed. No issues found. The PR looks good to merge.

Signed-off-by: Weizhen Wang <wangweizhen@pingcap.com>

D3Hunter · 2026-02-13T10:10:12Z

~~maybe just re-install golang 1.25 locally. i don't think we should pollute the main branch, just for workaround compiling tidb with go 1.26, we can wait golang fix it in later 1.26 fix version~~

~~or maybe you can file a PR to golang and fix the compile issue~~

Signed-off-by: Weizhen Wang <wangweizhen@pingcap.com>

pantheon-ai

✅ Code looks good. No issues found.

ti-chi-bot · 2026-02-13T10:21:34Z

@pantheon-ai[bot]: adding LGTM is restricted to approvers and reviewers in OWNERS files.

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✅ Code looks good. No issues found.

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hawkingrei · 2026-02-13T10:22:06Z

/retest

hawkingrei · 2026-02-13T10:45:18Z

/retest

hawkingrei · 2026-02-13T11:25:16Z

/retest

hawkingrei · 2026-02-13T11:35:17Z

/retest

codecov · 2026-02-13T13:39:39Z

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 77.5161%. Comparing base (3b69f59) to head (5d16af1).
⚠️ Report is 3 commits behind head on master.

Additional details and impacted files

@@               Coverage Diff                @@
##             master     #66254        +/-   ##
================================================
- Coverage   77.6934%   77.5161%   -0.1773%     
================================================
  Files          2006       1928        -78     
  Lines        548247     535790     -12457     
================================================
- Hits         425952     415324     -10628     
+ Misses       120635     120460       -175     
+ Partials       1660          6      -1654

Flag	Coverage Δ
integration	`41.4024% <ø> (-6.7858%)`	⬇️
unit	`76.6309% <ø> (+0.2946%)`	⬆️

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

Components	Coverage Δ
dumpling	`56.7974% <ø> (ø)`
parser	`∅ <ø> (∅)`
br	`48.7997% <ø> (-12.0881%)`	⬇️

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lance6716 · 2026-02-13T13:39:47Z

pkg/util/hack/map_abi.go

 // See the License for the specific language governing permissions and
 // limitations under the License.

+//go:build go1.25 && !go1.26


Where does the build process add go1.25 tag? I didn't find the doc related to it 😂

And seems we only need one version tag?

//go:build go1.25

//go:build go1.26

should be enough

https://github.com/kakkoyun/client_golang/blob/95d71bd58822329fd53f5c563b771ba49df5dc1b/prometheus/collectors/go_collector_go126_test.go#L12-L16

This way of writing is a standard.

Gemini says it's called ReleaseTags, golang will assign all tags <= current version, so we should use

//go:build go1.25 && !go1.26

However I didn't find the official document for it. Do you have more authorized materials for this feature?

lance6716 · 2026-02-13T13:45:14Z

maybe just re-install golang 1.25 locally. i don't think we should pollute the main branch, just for workaround compiling tidb with go 1.26, we can wait golang fix it in later 1.26 fix version

or maybe you can file a PR to golang and fix the compile issue

As #65761 and this comment, we can pin the version of golang used to compile TiDB. But if golang can't reliably pin a version for developer, as the situation of your development environment @hawkingrei , I'm good for this PR.

D3Hunter · 2026-02-13T14:20:44Z

/hold

please try fix the issue in golang itself, not workaround like this, it's an overkill for tidb repo, and the same issue might occur at other golang repo too, fixing the issue in golang is more appropriate

~~I hold it, in case anyone approve this pr, i think we need more discussion~~

Signed-off-by: Weizhen Wang <wangweizhen@pingcap.com>

hawkingrei · 2026-02-13T14:36:49Z

/hold

please try fix the issue in golang itself, not workaround like this, it's an overkill for tidb repo, and the same issue might occur at other golang repo too, fixing the issue in golang is more appropriate

I hold it, in case anyone approve this pr, i think we need more discussion

It's impossible unless Go itself reverts those map changes.

D3Hunter · 2026-02-13T15:03:53Z

/hold
please try fix the issue in golang itself, not workaround like this, it's an overkill for tidb repo, and the same issue might occur at other golang repo too, fixing the issue in golang is more appropriate
I hold it, in case anyone approve this pr, i think we need more discussion

It's impossible unless Go itself reverts those map changes.

seems i have some mis-understanding of the problem we are facing.

anyway i hate the idea that we have to file a PR like this every time golang release a new version. i prefer we use or modify the implementation of CRDB directly, if we want to estimate the memory taken by the map, and i check the number of callsites that depends on the memory is not that large

hawkingrei · 2026-02-13T18:45:37Z

/retest

solotzg · 2026-02-14T03:24:17Z

pkg/util/hack/map_abi_go126.go

+// Number of slots in a group.
+const mapGroupSlots = 1 << mapGroupSlotsBits // 8
+
+// $GOROOT/src/internal/runtime/maps/table.go:`type table struct`


Can AI tools help to add and check memory size & layout of such struct?

We can add a new skills for it. we can add this new skills in the next PR.

solotzg

lgtm

ti-chi-bot · 2026-02-14T03:24:50Z

@solotzg: adding LGTM is restricted to approvers and reviewers in OWNERS files.

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lgtm

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hawkingrei · 2026-02-14T03:45:04Z

/unhold

hawkingrei · 2026-02-14T05:23:09Z

maybe just re-install golang 1.25 locally. i don't think we should pollute the main branch, just for workaround compiling tidb with go 1.26, we can wait golang fix it in later 1.26 fix version
or maybe you can file a PR to golang and fix the compile issue

As #65761 and this comment, we can pin the version of golang used to compile TiDB. But if golang can't reliably pin a version for developer, as the situation of your development environment @hawkingrei , I'm good for this PR.

It won't work, just like when I upgraded my system and couldn't compile TiDB anymore.

ti-chi-bot · 2026-02-14T08:49:22Z

[LGTM Timeline notifier]

Timeline:

2026-02-14 08:49:21.983907831 +0000 UTC m=+2014.998601291: ☑️ agreed by YangKeao.

ti-chi-bot · 2026-02-14T08:49:22Z

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: pantheon-ai[bot], solotzg, YangKeao

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pkg/util/hack: split map ABI for go1.25 and go1.26

31af02f

ti-chi-bot bot added the release-note-none Denotes a PR that doesn't merit a release note. label Feb 13, 2026

ti-chi-bot bot added the size/XL Denotes a PR that changes 500-999 lines, ignoring generated files. label Feb 13, 2026

hawkingrei added 3 commits February 13, 2026 17:58

pkg/util/hack: align go1.26 map ABI naming with runtime

b19c713

pkg/util/hack: conditionally compile map ABI tests for go1.25 and go1.26

6ec0e42

update

ff9d313

Signed-off-by: Weizhen Wang <wangweizhen@pingcap.com>

ti-chi-bot bot added do-not-merge/needs-tests-checked and removed do-not-merge/needs-tests-checked labels Feb 13, 2026

use go1.26

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Signed-off-by: Weizhen Wang <wangweizhen@pingcap.com>

pantheon-ai bot approved these changes Feb 13, 2026

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lint: exclude revive var-naming for go126 map ABI mirror

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makefile: run revive via golangci-lint in lint target

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hawkingrei added 6 commits February 13, 2026 19:51

makefile: build golangci-lint with go.mod toolchain

d8e2c2c

lint: align revive rules with tools/check/revive.toml

7bf7e35

lint: exclude selected revive var-naming and dot-import findings

3049244

lint: restore master lint setup and exclude pkg/util/hack in revive

d0ce1c6

lint: use revive Exclude key for pkg/util/hack filters

809622b

lint: use top-level revive exclude for pkg/util/hack

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lance6716 reviewed Feb 13, 2026

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lint: exclude pkg/util/hack via revive CLI flags

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update

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Signed-off-by: Weizhen Wang <wangweizhen@pingcap.com>

ti-chi-bot bot added size/XL Denotes a PR that changes 500-999 lines, ignoring generated files. and removed size/XXL Denotes a PR that changes 1000+ lines, ignoring generated files. labels Feb 13, 2026

build: skip lint on pkg/util/hack and clean grep regex

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stefanb mentioned this pull request Feb 13, 2026

go 1.26.0, go@1.25 1.25.7 (new formula) Homebrew/homebrew-core#258912

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