Use PHP_VERSION_ID to select Pdo\Mysql constants in Mysql::connect()

[77web]

Follow-up to #27, addressing #27 (comment)

Changes

• Pdo\Mysql was added in PHP 8.4.0, not 8.1 (docs). Fix the comment.
• Replace class_exists('Pdo\Mysql') with PHP_VERSION_ID >= 80400:
  • avoids running the autoloader chain on every connect() on PHP < 8.4
  • a userland Pdo\Mysql class can no longer be misdetected
  • same approach as CakePHP 4.x/5.x
• Route the SSL options (ssl_key / ssl_cert / ssl_ca) through Pdo\Mysql::ATTR_SSL_* too, so they no longer trigger PHP 8.5 deprecations.

Verification

• php -l passes on PHP 8.1 / 8.4 / 8.5 (official Docker images)
• With pdo_mysql on PHP 8.4 / 8.5, all the Pdo\Mysql::ATTR_* constants used here resolve without deprecation warnings

🤖 Generated with Claude Code

[basi]

Thanks for the follow-up. The code change looks correct and covers the code items from the #27 review: the SSL constants, the "8.1" comment and the PHP_VERSION_ID check.

Checked

• On PHP 8.4+, pdo_mysql registers PDO::MYSQL_ATTR_* and Pdo\Mysql::ATTR_* from the same C values (on 8.5 the former as deprecated aliases), so the flag keys passed to new PDO() are unchanged. The ssl_* → ATTR_SSL_* mapping matches the old code.
• After this change, the only code references to PDO::MYSQL_ATTR_* left in the repository are in the < 8.4 branch.
• All five constants are resolved at the top of connect(). The 8.0 MySQL job runs the PDO::MYSQL_ATTR_* branch and the 8.4 job runs the Pdo\Mysql branch, even though the CI config sets neither encoding nor ssl_*.
• Without pdo_mysql, DboSource::__construct() throws MissingConnectionException via enabled() before connect() runs, so referencing Pdo\Mysql directly adds no new failure mode.

Remaining from the #27 follow-up scope

• Should: the README Changelog entry is still missing. Could you add it to this PR under a new ### YYYY-MM-DD heading? For example:

  - Fix the PHP 8.5 `PDO::MYSQL_ATTR_*` deprecations in the MySQL datasource: on PHP >= 8.4, `Mysql::connect()` uses the `Pdo\Mysql::ATTR_*` constants, including the SSL ones (based on kamilwylegala/cakephp2-php8#86). Apps passing `PDO::MYSQL_ATTR_*` in the datasource `flags` option should switch to `Pdo\Mysql::ATTR_*` on PHP >= 8.4 as well.

  I'll approve once it's in.

Optional

• Upstream master still has the class_exists() check, the "8.1" comment and PDO::MYSQL_ATTR_SSL_*, so this change could be sent upstream too.

[basi]

Reviewed commit 75f5331. No additional code defects found. The version guard and SSL attribute mappings are correct, and all five replacement constants preserve the existing option keys.

CI passes all four jobs. I also verified constant equivalence on PHP 8.4 and syntax on PHP 8.5; PHP 8.5 SSL connections were not exercised.

The README Changelog entry requested in the existing review remains outstanding.

[77web]

@basi Thank you for your review. I added a changelog in README.md.

[basi]

Thanks for adding the Changelog entry. Re-checked 25dc516: it only adds the ### 2026-09-30 section to README.md, with the wording suggested in the earlier review, and Mysql.php is unchanged from 75f5331. CI is green on all four jobs. Approving.