expression: add cast for eq expr when doing constant propagation | tidb-test=pr/2592

[guo-shaoge]

What problem does this PR solve?

Issue Number: close #57247

Problem Summary: check #57247 (comment)

What changed and how does it work?

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.

expression: add cast for eq expr when doing constant propagation

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 73.5391%. Comparing base (9bcae5e) to head (3b3fea9).
⚠️ Report is 27 commits behind head on master.

Additional details and impacted files

@@               Coverage Diff                @@
##             master     #63327        +/-   ##
================================================
+ Coverage   72.7787%   73.5391%   +0.7604%     
================================================
  Files          1832       1832                
  Lines        495715     499757      +4042     
================================================
+ Hits         360775     367517      +6742     
+ Misses       113001     110554      -2447     
+ Partials      21939      21686       -253     

Flag	Coverage Δ
integration	42.5367% <100.0000%> (?)
unit	72.6325% <100.0000%> (+0.3819%)	⬆️

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

Components	Coverage Δ
dumpling	52.8700% <ø> (ø)
parser	∅ <ø> (∅)
br	46.5345% <ø> (+0.0228%)	⬆️

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
• 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.

[guo-shaoge]

/test mysql-test

[tiprow]

@guo-shaoge: The specified target(s) for /test were not found.
The following commands are available to trigger required jobs:

• /test fast_test_tiprow
• /test tidb_parser_test

Use /test all to run all jobs.

In response to this:

/test mysql-test

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes-sigs/prow repository.

[guo-shaoge]

/test mysql-test

[tiprow]

@guo-shaoge: The specified target(s) for /test were not found.
The following commands are available to trigger required jobs:

• /test fast_test_tiprow
• /test tidb_parser_test

Use /test all to run all jobs.

In response to this:

/test mysql-test

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes-sigs/prow repository.

[ti-chi-bot]

[LGTM Timeline notifier]

Timeline:

• 2025-09-03 03:28:59.01396293 +0000 UTC m=+929230.891793874: ☑️ agreed by hawkingrei.
• 2025-09-04 02:06:52.875737998 +0000 UTC m=+59156.858835446: ☑️ agreed by AilinKid.

[windtalker]

lgtm

[ti-chi-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: AilinKid, hawkingrei, windtalker

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

The pull request process is described here

Needs approval from an approver in each of these files:

• pkg/expression/OWNERS [windtalker]

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

[guo-shaoge]

/test check_dev_2

[ti-chi-bot]

@guo-shaoge: The specified target(s) for /test were not found.
The following commands are available to trigger required jobs:

/test build

/test check-dev

/test check-dev2

/test mysql-test

/test pull-br-integration-test

/test pull-build-next-gen

/test pull-integration-ddl-test

/test pull-integration-e2e-test

/test pull-integration-realcluster-test-next-gen

/test pull-lightning-integration-test

/test pull-mysql-client-test

/test pull-mysql-client-test-next-gen

/test pull-unit-test-ddlv1

/test unit-test

The following commands are available to trigger optional jobs:

/test pingcap/tidb/canary_ghpr_unit_test

/test pull-br-integration-test-next-gen

/test pull-common-test

/test pull-e2e-test

/test pull-error-log-review

/test pull-integration-common-test

/test pull-integration-copr-test

/test pull-integration-ddl-test-next-gen

/test pull-integration-e2e-test-next-gen

/test pull-integration-jdbc-test

/test pull-integration-mysql-test

/test pull-integration-nodejs-test

/test pull-integration-python-orm-test

/test pull-mysql-test-next-gen

/test pull-sqllogic-test

/test pull-tiflash-integration-test

/test pull-unit-test-next-gen

Use /test all to run the following jobs that were automatically triggered:

pingcap/tidb/ghpr_build

pingcap/tidb/ghpr_check

pingcap/tidb/ghpr_check2

pingcap/tidb/ghpr_mysql_test

pingcap/tidb/ghpr_unit_test

pingcap/tidb/pull_build_next_gen

pingcap/tidb/pull_integration_ddl_test

pingcap/tidb/pull_integration_e2e_test

pingcap/tidb/pull_integration_realcluster_test_next_gen

pingcap/tidb/pull_mysql_client_test

pingcap/tidb/pull_mysql_client_test_next_gen

pull-error-log-review

In response to this:

/test check_dev_2

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes-sigs/prow repository.

[tiprow]

@guo-shaoge: The specified target(s) for /test were not found.
The following commands are available to trigger required jobs:

• /test fast_test_tiprow
• /test tidb_parser_test

Use /test all to run all jobs.

In response to this:

/test check_dev_2

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes-sigs/prow repository.

[tiprow]

@ti-chi-bot[bot]: The specified target(s) for /test were not found.
The following commands are available to trigger required jobs:

• /test fast_test_tiprow
• /test tidb_parser_test

Use /test all to run all jobs.

In response to this:

@guo-shaoge: The specified target(s) for /test were not found.
The following commands are available to trigger required jobs:

/test build

/test check-dev

/test check-dev2

/test mysql-test

/test pull-br-integration-test

/test pull-build-next-gen

/test pull-integration-ddl-test

/test pull-integration-e2e-test

/test pull-integration-realcluster-test-next-gen

/test pull-lightning-integration-test

/test pull-mysql-client-test

/test pull-mysql-client-test-next-gen

/test pull-unit-test-ddlv1

/test unit-test

The following commands are available to trigger optional jobs:

/test pingcap/tidb/canary_ghpr_unit_test

/test pull-br-integration-test-next-gen

/test pull-common-test

/test pull-e2e-test

/test pull-error-log-review

/test pull-integration-common-test

/test pull-integration-copr-test

/test pull-integration-ddl-test-next-gen

/test pull-integration-e2e-test-next-gen

/test pull-integration-jdbc-test

/test pull-integration-mysql-test

/test pull-integration-nodejs-test

/test pull-integration-python-orm-test

/test pull-mysql-test-next-gen

/test pull-sqllogic-test

/test pull-tiflash-integration-test

/test pull-unit-test-next-gen

Use /test all to run the following jobs that were automatically triggered:

pingcap/tidb/ghpr_build

pingcap/tidb/ghpr_check

pingcap/tidb/ghpr_check2

pingcap/tidb/ghpr_mysql_test

pingcap/tidb/ghpr_unit_test

pingcap/tidb/pull_build_next_gen

pingcap/tidb/pull_integration_ddl_test

pingcap/tidb/pull_integration_e2e_test

pingcap/tidb/pull_integration_realcluster_test_next_gen

pingcap/tidb/pull_mysql_client_test

pingcap/tidb/pull_mysql_client_test_next_gen

pull-error-log-review

In response to this:

/test check_dev_2

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes-sigs/prow repository.

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes-sigs/prow repository.

[hawkingrei]

/retest