fix(wren): multiline subquery wrap to prevent trailing comment swallowing (#2733)

[FrancescoCastaldi]

Summary

Closes #2733.

When user SQL ends in a --\ line comment, wrapping the SQL in a single-line subquery (\SELECT * FROM ({sql}) AS ...) causes the closing parenthesis, table alias, and LIMIT clause to be swallowed by the line comment.

This was previously fixed for \postgres\ (#2728), \oracle,
edshift, and \ rino\ (#2736), and \�igquery\ / \duckdb. This PR finishes the remaining connectors identified in #2733:

• \canner.py\ (\query\ and \dry_run)
• \clickhouse.py\ (\query\ and \dry_run)
• \databricks.py\ (\dry_run)
• \datafusion.py\ (\query)

Changes

• Updated \canner.py, \clickhouse.py, \databricks.py, and \datafusion.py\ to use multiline wrapping (\SELECT * FROM (\n{sql}\n) AS ...).
• Updated existing unit test assertions to match multiline wrap.
• Added test cases verifying query/dry_run survive trailing line comments in:
  • \ est_canner_semicolon.py\
  • \ est_clickhouse_helpers.py\
  • \ est_databricks_semicolon.py\
  • \ est_datafusion_semicolon.py\

Verification

• Ran .venv\Scripts\python -m pytest\ on all affected unit tests: 75/75 passed.
• Ran
  uff check\ and
  uff format --check: all clean.

Summary by CodeRabbit

• Bug Fixes
  • Fixed query execution and dry-run errors caused by trailing line comments when a row limit is applied.
  • Kept generated query wrappers valid across supported connectors while preserving trailing comments.
• Tests
  • Added coverage for trailing comments in limited queries and dry runs across multiple connectors.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

• Configuration used: Repository UI
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• Plan: Advanced
• Run ID: f42e003e-884b-4084-8aac-46d63b18c8ac

📥 Commits

Reviewing files that changed from the base of the PR and between 5492391 and 0701e30.

📒 Files selected for processing (1)

• core/wren/src/wren/connector/databricks.py

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Walkthrough

Canner, ClickHouse, Databricks, and DataFusion now place inner SQL on separate lines in the affected subquery wrappers. Tests verify the formatting and cover trailing line comments in limited-query and dry-run paths.

Changes

SQL wrapper fix

Layer / File(s)	Summary
Connector wrapper formatting core/wren/src/wren/connector/canner.py, clickhouse.py, databricks.py, datafusion.py	The affected query and dry-run paths place inner SQL on separate lines inside subquery wrappers. Existing limits and execution behavior remain unchanged.
Wrapper regression coverage core/wren/tests/unit/test_canner_semicolon.py, test_clickhouse_helpers.py, test_databricks_semicolon.py, test_datafusion_semicolon.py	Tests update expected wrapper formatting and cover trailing line comments in limited-query and dry-run paths. ClickHouse tests also reformat two URL strings. Other test edits reorder imports and remove a stale mock-cursor line.

Priority: ➖ Normal

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

Change: Bug fix · Severity of issue fixed: Medium

Merge Risk: ⚪ Minimal · up to 0701e

The affected wrappers separate trailing line comments from closing syntax, and the regression tests cover those cases. No actionable merge risk remains in the reviewed changes.

🚥 Pre-merge checks | ✅ 2 | ❌ 1 | ❓ 2

❌ Failed checks (1 warning, 2 inconclusive)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 42.86% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 28 functions across 8 files.	Write docstrings for the functions missing them to satisfy the coverage threshold.
Linked Issues check	❓ Inconclusive	The linked issue assessment could not be completed.	Retry the assessment when the required review evidence is available.
Out of Scope Changes check	❓ Inconclusive	The linked issue assessment could not be completed.	Retry the assessment when the required review evidence is available.

✅ Passed checks (2 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly identifies the multiline subquery change and the trailing-comment problem it fixes.
Description check	✅ Passed	The description covers the change, affected connectors, tests, and verification. It explains the failure but does not include the required reproduction and actual error output, and it omits the duplic…

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_{A rabbit checks the SQL line,
And moves the wrap to make it fine.
A comment rests, then ends in place,
The closing bracket keeps its space.
Limits wait beyond the line,
While tests confirm the new design.}

_{Comment @coderabbitai help to get the list of available commands.}

[goldmedal]

@FrancescoCastaldi, thanks for working on this. There are some conflicts. Could you resolve them?

[FrancescoCastaldi]

@goldmedal Rebased on latest main and resolved the conflicts in canner.py and databricks.py. All 75 connector unit tests are passing cleanly.

[goldmedal]

Thanks @FrancescoCastaldi 👍