Remove legacy SQLite driver

[JanJakes]

Summary

Remove the legacy, token-based MySQL-to-SQLite translator and the `WP_SQLITE_AST_DRIVER` feature flag. The AST-based driver is now the only driver.

Changes

• Delete 6 legacy driver files (~8,700 lines) and 7 legacy test files (~5,000 lines), along with the root `phpunit.xml.dist` and `composer.json` test command.
• Remove `WP_SQLITE_AST_DRIVER` conditionals and `WP_SQLite_Translator` branches from `class-wp-sqlite-db.php`, `admin-page.php`, `constants.php`, `wp-mysql-proxy.php`, and `phpcs.xml.dist`.
• Remove legacy driver CI test step and unused `phpunit-config` workflow parameter.
• Remove DB_NAME fallback in `db.php` that was kept for legacy driver compatibility.
• Fix dead `get_error_message()` call in `install-functions.php` left over from the legacy driver API.
• Update docs to reflect the removal (`AGENTS.md`, `README.md`, `readme.txt`).

Test plan

• New driver tests pass (635 tests)
• PHPCS clean
• CI passes

[joaopedrofrech]

This is amazing! are we finally moving to the new driver as default?

[chubes4]

+1 to this! Would solve a problem for me when using https://github.com/Automattic/studio for local dev

Thanks for your efforts!

[Copilot]

Pull request overview

This PR removes the legacy token-based MySQL→SQLite translator (and its tests/tooling) and eliminates the WP_SQLITE_AST_DRIVER feature flag so the AST-based driver becomes the only supported implementation across the repo.

Changes:

• Deletes legacy driver implementation + legacy PHPUnit test suite/configuration.
• Removes WP_SQLITE_AST_DRIVER conditionals across the WordPress plugin and MySQL proxy tooling, defaulting to the AST driver.
• Simplifies CI/workflow inputs and updates docs/setup scripts to match the single-driver world.

Reviewed changes

Copilot reviewed 25 out of 28 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
wp-setup.sh	Removes WP_SQLITE_AST_DRIVER env injection from local wp-env overrides.
tests/wp-sqlite-schema.php	Removes legacy test schema file.
tests/WP_SQLite_Query_Tests.php	Removes legacy query tests targeting the translator.
tests/WP_SQLite_Query_RewriterTests.php	Removes legacy query rewriter unit tests.
tests/WP_SQLite_PDO_User_Defined_Functions_Tests.php	Removes legacy UDF unit tests.
tests/WP_SQLite_Metadata_Tests.php	Removes legacy information_schema/metadata tests targeting translator behavior.
tests/bootstrap.php	Removes legacy PHPUnit bootstrap and polyfills used by deleted tests.
README.md	Updates docs to remove legacy plugin PHPUnit test commands; keeps E2E guidance.
phpunit.xml.dist	Removes root PHPUnit config (legacy suite).
phpcs.xml.dist	Drops PHPCS exclude for the deleted legacy translator file.
packages/plugin-sqlite-database-integration/wp-includes/sqlite/php-polyfills.php	Removes legacy PHP 8.0 polyfills (no longer needed by deleted code).
packages/plugin-sqlite-database-integration/wp-includes/sqlite/install-functions.php	Uses WP_SQLite_Driver unconditionally during schema creation.
packages/plugin-sqlite-database-integration/wp-includes/sqlite/db.php	Always loads the new driver loader; removes feature-flag logic and DB_NAME fallback behavior.
packages/plugin-sqlite-database-integration/wp-includes/sqlite/class-wp-sqlite-token.php	Deletes legacy lexer token model.
packages/plugin-sqlite-database-integration/wp-includes/sqlite/class-wp-sqlite-query-rewriter.php	Deletes legacy query rewriter.
packages/plugin-sqlite-database-integration/wp-includes/sqlite/class-wp-sqlite-pdo-user-defined-functions.php	Deletes legacy UDF implementation used by the translator.
packages/plugin-sqlite-database-integration/wp-includes/sqlite/class-wp-sqlite-lexer.php	Deletes legacy lexer implementation.
packages/plugin-sqlite-database-integration/wp-includes/sqlite/class-wp-sqlite-db.php	Removes translator branches; assumes WP_SQLite_Driver everywhere.
packages/plugin-sqlite-database-integration/readme.txt	Removes outdated licensing note for PHPMyAdmin/sql-parser code that’s no longer shipped.
packages/plugin-sqlite-database-integration/constants.php	Removes env-var-based enabling of WP_SQLITE_AST_DRIVER.
packages/plugin-sqlite-database-integration/admin-page.php	Removes “(AST)” suffix since AST is now the only driver.
packages/mysql-proxy/bin/wp-mysql-proxy.php	Removes hard-coded WP_SQLITE_AST_DRIVER define.
composer.json	Removes root test script (no root PHPUnit suite anymore).
AGENTS.md	Updates contributor docs to remove legacy driver references and plugin PHPUnit test commands.
.github/workflows/phpunit-tests.yml	Removes unused workflow parameter wiring for phpunit config.
.github/workflows/phpunit-tests-run.yml	Removes unused phpunit-config input/env and legacy-driver CI step.

Comments suppressed due to low confidence (1)

packages/plugin-sqlite-database-integration/wp-includes/sqlite/install-functions.php:58

• This catch block indexes into $err->errorInfo, but WP_SQLite_Driver_Exception (thrown by the new driver) extends PDOException without necessarily setting errorInfo. On such failures (e.g. parse errors), this can trigger warnings and lose the real error context. Consider falling back to $err->getMessage() (and/or $err->getCode()) when errorInfo is missing, and only indexing errorInfo when it’s an array with expected offsets.

	} catch ( PDOException $err ) {
		$err_data = $err->errorInfo; // phpcs:ignore WordPress.NamingConventions.ValidVariableName.UsedPropertyNotSnakeCase
		$err_code = $err_data[1];
		$translator->rollback();
		$message  = sprintf(

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[JanJakes]

This is amazing! are we finally moving to the new driver as default?

@joaopedrofrech Yes, coming soon 🙂