Fix: Skip sandbox line in MariaDB dump files during import

[iamsandeepdahiya]

Summary

This PR addresses a compatibility issue introduced by a recent MariaDB security fix (MDEV-21178), which causes wp db import to fail when importing SQL dump files generated by newer versions of MariaDB.

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Background

To mitigate a serious security vulnerability, MariaDB added a new "sandbox mode" that disables potentially dangerous client-side commands. This mode is triggered by placing the following directive at the top of a dump file:

/*!999999\ - enable the sandbox mode */

While this is safe for newer MariaDB clients, it breaks compatibility with:

• Older MariaDB clients
• All versions of MySQL clients
• WP-CLI's wp db import command

This directive causes a SQL syntax error when encountered during import:

ERROR 1064 (42000): You have an error in your SQL syntax...

This problem is being tracked in #258.

Solution

This patch introduces a safeguard into the import() method:

• It reads the first line of the SQL dump.
• If the line contains the sandbox directive (/*!999999), it creates a temporary file that skips the first line.
• The modified file is then passed into the SOURCE command for import.
• If the directive is not found, import proceeds as normal.

[codecov]

Codecov Report

Attention: Patch coverage is 12.50000% with 14 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
src/DB_Command.php	12.50%	14 Missing ⚠️

📢 Thoughts on this report? Let us know!

[mrsdizzie]

I don't think it should be the responsibility of wp cli to modify these files directly. Also we can't create temporary files of unknown size -- I regularly come across dump files that are many GB. This is very easy to address outside of wp cli if you are importing dump files across incompatible versions of MariaDB (just remove the incompatible line or strip it when exporting).