expression: ignore TypeNULL in HandleBinaryLiteral

[YangKeao]

What problem does this PR solve?

Issue Number: close #49526

Problem Summary:

What changed and how does it work?

Ignore the TypeNull in HandleBinaryLiteral, as the castStringToString will actually do nothing for NULL (except changing the type).

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

None

[windtalker]

What is the explain result without this pr?

[YangKeao]

mysql> explain select null as a union all select 'a' as a;
+------------------------+---------+------+---------------+---------------------------------------------------+
| id                     | estRows | task | access object | operator info                                     |
+------------------------+---------+------+---------------+---------------------------------------------------+
| Union_8                | 2.00    | root |               |                                                   |
| ├─Projection_10        | 1.00    | root |               | cast(from_binary(<nil>), var_string(1))->Column#3 |
| │ └─TableDual_11       | 1.00    | root |               | rows:1                                            |
| └─Projection_12        | 1.00    | root |               | a->Column#3                                       |
|   └─TableDual_13       | 1.00    | root |               | rows:1                                            |
+------------------------+---------+------+---------------+---------------------------------------------------+
5 rows in set (0.00 sec)

[codecov]

Codecov Report

Merging #49527 (36817d5) into master (074af10) will increase coverage by 0.5642%.
Report is 2 commits behind head on master.
The diff coverage is 13.0434%.

Additional details and impacted files

@@               Coverage Diff                @@
##             master     #49527        +/-   ##
================================================
+ Coverage   70.9977%   71.5619%   +0.5642%     
================================================
  Files          1368       1418        +50     
  Lines        399517     415243     +15726     
================================================
+ Hits         283648     297156     +13508     
- Misses        96068      99289      +3221     
+ Partials      19801      18798      -1003     

Flag	Coverage Δ
integration	43.8524% <13.0434%> (?)
unit	71.0009% <ø> (+0.0031%)	⬆️

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

Components	Coverage Δ
dumpling	53.9663% <ø> (ø)
parser	∅ <ø> (∅)
br	47.7771% <ø> (-5.1177%)	⬇️

[windtalker]

LGTM

[ti-chi-bot]

[LGTM Timeline notifier]

Timeline:

• 2023-12-17 09:33:55.343793067 +0000 UTC m=+780726.381019978: ☑️ agreed by tangenta.
• 2023-12-17 09:46:24.341434046 +0000 UTC m=+781475.378660968: ☑️ agreed by windtalker.

[ti-chi-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: jackysp, tangenta, windtalker

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[wuhuizuo]

/test all

[wuhuizuo]

/test all

[wuhuizuo]

/test all

[wuhuizuo]

/test all

[wuhuizuo]

/test ?

[ti-chi-bot]

@wuhuizuo: The following commands are available to trigger required jobs:

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[wuhuizuo]

/retest

[YangKeao]

/retest

[YangKeao]

/retest

[wuhuizuo]

/test check-dev2

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@wuhuizuo: The specified target(s) for /test were not found.
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Use /test all to run all jobs.

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[wuhuizuo]

/retest

[ti-chi-bot]

In response to a cherrypick label: new pull request created to branch release-6.5: #49531.

[ti-chi-bot]

In response to a cherrypick label: new pull request created to branch release-7.1: #49532.

[ti-chi-bot]

In response to a cherrypick label: new pull request created to branch release-7.5: #49533.

[ti-chi-bot]

In response to a cherrypick label: new pull request created to branch release-6.1: #49534.