expression: use maximum length for integer display

[dveeden]

What problem does this PR solve?

Issue Number: close #56462 close #45338 close #41719

Problem Summary:

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.

Issues related to casting integers with a non-default display width to strings have been fixed.

[ti-chi-bot]

Skipping CI for Draft Pull Request.
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You can still manually trigger a test run with /test all

[tiprow]

Hi @dveeden. Thanks for your PR.

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[dveeden]

/ok-to-test

[dveeden]

/check-issue-triage-complete

[dveeden]

This looks good:

mysql-8.0.11-TiDB-v8.4.0-alpha-325-g74034d4ac2-dirty> DROP TABLE IF EXISTS test.t;
Query OK, 0 rows affected (0.02 sec)

mysql-8.0.11-TiDB-v8.4.0-alpha-325-g74034d4ac2-dirty> CREATE TABLE test.t (id bigint(11) UNSIGNED PRIMARY KEY);
Query OK, 0 rows affected (0.01 sec)

mysql-8.0.11-TiDB-v8.4.0-alpha-325-g74034d4ac2-dirty> INSERT INTO test.t VALUES (1234567890123456);
Query OK, 1 row affected (0.00 sec)

mysql-8.0.11-TiDB-v8.4.0-alpha-325-g74034d4ac2-dirty> SELECT IFNULL(id, 'abcdef') FROM test.t;
+----------------------+
| IFNULL(id, 'abcdef') |
+----------------------+
| 1234567890123456     |
+----------------------+
1 row in set (0.00 sec)

This should result in a warning and truncation, but no longer does:

mysql-8.0.11-TiDB-v8.4.0-alpha-325-g74034d4ac2-dirty> WITH a AS (SELECT 1234 v) SELECT CAST(v AS CHAR(2)) FROM a;
+--------------------+
| CAST(v AS CHAR(2)) |
+--------------------+
| 1234               |
+--------------------+
1 row in set (0.00 sec)

[Defined2014]

Hi @dveeden, is this PR ready for review? And I think this PR also could fix #45338

Maybe we should modified setFlenFromArgs function to fix it.

[dveeden]

Hi @dveeden, is this PR ready for review?

Not yet, the problem. There is a regression that needs to be fixed. See #56463 (comment) for details.

And I think this PR also could fix #45338

Yes, correct.

Maybe we should modified setFlenFromArgs function to fix it.

[dveeden]

Maybe we should modified setFlenFromArgs function to fix it.

Yes. Thanks!

[ti-chi-bot]

[LGTM Timeline notifier]

Timeline:

• 2024-10-11 13:20:24.773985278 +0000 UTC m=+18021.922895111: ☑️ agreed by Defined2014.
• 2024-10-12 08:58:20.354477799 +0000 UTC m=+88697.503387630: ☑️ agreed by lance6716.

[lance6716]

/assign @windtalker

[ti-chi-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: Defined2014, lance6716, XuHuaiyu

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• OWNERS [Defined2014,XuHuaiyu,lance6716]
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[dveeden]

/retest

[dveeden]

/retest

[dveeden]

/retest

[ti-chi-bot]

In response to a cherrypick label: new pull request created to branch release-7.1: #56926.

[ti-chi-bot]

In response to a cherrypick label: new pull request created to branch release-8.1: #56927.

[ti-chi-bot]

In response to a cherrypick label: new pull request created to branch release-7.5: #56929.