expression, planner: fix ambiguous column name in overflow error message

[minleejae]

What problem does this PR solve?

Issue Number: close #17993

Problem Summary: When an arithmetic overflow occurs, the error message displays "Column#N" instead of the actual column name, making it difficult for users to identify which column caused the issue.

Before:

mysql> SELECT col3 from t5 where t5.col7 * ABS(-9223372036854775807);
ERROR 1690 (22003): BIGINT value is out of range in '(Column#0 * 9223372036854775807)'

After:

mysql> SELECT col3 from t5 where t5.col7 * ABS(-9223372036854775807);
ERROR 1690 (22003): BIGINT value is out of range in '(t5.col7 * 9223372036854775807)'

What changed and how does it work?

The root cause is that the OrigName field of Column struct was not being set in certain code paths:

1. expression_rewriter.go: In the toColumn() function, when a column is resolved from table metadata directly (fallback path when planCtx == nil), the OrigName was not set.

2. task.go: In the appendExpr() function used for MPP projection columns, the OrigName was not set for newly created columns.

This fix ensures OrigName is properly set in both locations, so error messages display meaningful column names.

Check List

Tests

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

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

Fix the issue that overflow error messages display "Column#N" instead of the actual column name, improving error message clarity for debugging.

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[tiprow[bot]]

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[codecov[bot]]

Codecov Report

:white_check_mark: All modified and coverable lines are covered by tests. :white_check_mark: Project coverage is 74.5117%. Comparing base (dd1df3f) to head (100c2de). :warning: Report is 94 commits behind head on master.

Additional details and impacted files

@@               Coverage Diff                @@
##             master     #64887        +/-   ##
================================================
- Coverage   74.7253%   74.5117%   -0.2136%     
================================================
  Files          1888       1876        -12     
  Lines        515164     527891     +12727     
================================================
+ Hits         384958     393341      +8383     
- Misses       106388     112589      +6201     
+ Partials      23818      21961      -1857     

Flag	Coverage Δ
integration	42.4430% <0.0000%> (-5.7155%)	:arrow_down:
unit	73.9186% <100.0000%> (+1.6280%)	:arrow_up:

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	45.4765% <0.0000%> (-17.7199%)	:arrow_down:

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[lance6716]

Hi @minleejae you can see TestIssue59877 is failed in CI. The output format is changed which is not acceptable to me. Please limit the change scopr of your PR.

[minleejae]

/retest

[minleejae]

Hi @lance6716 I've removed the task.go changes that were causing the TestIssue59877 failure. The fix now only modifies expression_rewriter.go to set OrigName in the fallback path.

[lance6716]

/cc @windtalker

[ti-chi-bot[bot]]

[LGTM Timeline notifier]

Timeline:

• 2025-12-08 02:28:43.149809439 +0000 UTC m=+835267.963587010: :ballot_box_with_check: agreed by lance6716.
• 2025-12-10 00:34:59.041116328 +0000 UTC m=+1001243.854893900: :ballot_box_with_check: agreed by windtalker.

[hawkingrei]

/retest

[hawkingrei]

/retest

[ti-chi-bot[bot]]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: hawkingrei, lance6716, windtalker

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Needs approval from an approver in each of these files:

• ~~pkg/expression/OWNERS~~ [windtalker]
• ~~pkg/planner/OWNERS~~ [hawkingrei]

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[hawkingrei]

/test all

[tiprow[bot]]

@minleejae: The following tests 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	100c2de5e5db5245a4c22bdb15b4952f28594c14	link	true	/test fast_test_tiprow
tidb_parser_test	100c2de5e5db5245a4c22bdb15b4952f28594c14	link	true	/test tidb_parser_test

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[ti-chi-bot[bot]]

@minleejae: 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
idc-jenkins-ci-tidb/mysql-test	100c2de5e5db5245a4c22bdb15b4952f28594c14	link	true	/test mysql-test

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