refactor(mysql): strip trailing semicolon on unlimited query path for connector consistency

[Bartok9]

Summary

Strip trailing semicolons on MySQL unlimited queries.

Motivation

LIMIT and EXPLAIN already stripped; unlimited left terminators intact.

Verification

.venv/bin/python -m pytest tests/unit/test_mysql_semicolon_unlimited.py -q
2 passed

Summary by CodeRabbit

• Bug Fixes

  • Improved MySQL query handling by stripping trailing semicolons from unlimited queries before execution.
  • Kept the existing limited-query behavior, ensuring queries remain clean and still include LIMIT when specified.

• Tests

  • Added unit tests covering semicolon removal for both unlimited and limited query paths.

[coderabbitai]

Walkthrough

Changes

MySQL query terminator normalization

Layer / File(s)	Summary
Normalize and test query terminators core/wren/src/wren/connector/mysql.py, core/wren/tests/unit/test_mysql_semicolon_unlimited.py	MySqlConnector.query strips trailing semicolons when no limit is provided. Unit tests verify semicolon-free unlimited execution and limited-path behavior with LIMIT 2.

Estimated code review effort: 2 (Simple) | ~10 minutes

Possibly related issues

• Strip trailing semicolon on the unlimited query() path across connectors #2497: Addresses trailing-semicolon removal in connector unlimited query paths, including MySqlConnector.query.

Possibly related PRs

• Canner/WrenAI#2557: Modifies MySqlConnector.query to strip semicolons on unlimited queries and adds corresponding tests.
• Canner/WrenAI#2593: Adds MySQL unlimited-path semicolon stripping and semicolon-free SQL assertions.
• Canner/WrenAI#2594: Applies the same unlimited query-path normalization pattern to another connector with tests.

Suggested reviewers: goldmedal

Poem

A bunny hops through SQL bright,
Trims semicolons left and right.
Unlimited queries now run clean,
Limited ones keep LIMIT keen.
Tests cheer at execution night!

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly matches the main change: stripping trailing semicolons on the unlimited MySQL query path for consistency.

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

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[goldmedal]

Code review

No blocking issues. The change is correct — strip_trailing_semicolon is already imported at mysql.py:21-24, and it matches the pattern already on main for bigquery, duckdb and redshift (#2482). Two notes.

1. This is a consistency change, not a fix. cursor.execute("SELECT 1;") succeeds against MySQL today, so nothing user-visible is repaired. The fix(...) prefix and the "Motivation" section read as though a broken path is being closed. Worth relabelling so the changelog doesn't imply that.

2. Dead assertion in the new test.

WrenAI/core/wren/tests/unit/test_mysql_semicolon_unlimited.py

Lines 42 to 45 in f27b6f3

	sent = cursor.execute.call_args[0][0]
	assert "LIMIT 2" in sent
	assert ";)" not in sent
	assert not sent.rstrip().endswith(";")

assert ";)" not in sent is copy-paste residue from the subquery-wrapping connectors. MySQL's _apply_limit appends \nLIMIT n and never wraps the SQL in parentheses, so ";)" cannot occur regardless of the code under test. The line below it already covers the intent.

[Bartok9]

Thanks @goldmedal — both spot-on.

1. Retitled to refactor(...) since MySQL's cursor.execute("SELECT 1;") succeeds today; this aligns the connector with bigquery/duckdb/redshift (fix(redshift): strip trailing semicolon on unlimited query path #2482) rather than repairing a broken path.
2. Dropped the dead assert ";)" not in sent — copy-paste residue from the subquery-wrapping connectors; MySQL's _apply_limit only appends \nLIMIT n and never parenthesizes, so it could never trigger. The trailing-semicolon assertion below already covers the intent.

[goldmedal]

Thanks @Bartok9 👍