Clean up native parser follow-ups (#394)

## What it does

Cleans up the native parser follow-up from #381 so the merged code reads
as permanent code, not review scaffolding.

It replaces duplicated inline verifier logic with one
`tests/tools/verify-native-parser-extension.php` entry point for
`mysql-on-sqlite`. The parser-extension workflow and PHPUnit bootstrap
both call the same verifier:

```bash
php -d extension=../php-ext-wp-mysql-parser/target/debug/libwp_mysql_parser.so \
  tests/tools/verify-native-parser-extension.php
```

It also collapses `WP_PDO_MySQL_On_SQLite::create_parser()` to one token
selection and one parser reset/create return, and rewrites native parser
test comments to describe behavior instead of PR review history.

## Rationale

#381 landed functional native parser support, but a few follow-up
surfaces still carried review-era wording and copied verifier blocks.
That makes future changes harder to read and easier to drift: native
parser routing, Rust AST handle storage, wrapper identity, and
materialized child behavior were being checked in multiple places.

The verifier now pins that runtime contract from one script: extension
loaded, `WP_MySQL_Lexer` resolves native, `WP_MySQL_Parser` delegates to
`WP_MySQL_Native_Parser`, the SQLite driver returns a native-backed AST,
native wrapper handle properties are absent, child identity is stable,
and materialized child mutations survive.

## Implementation

Added `wp_sqlite_verify_native_parser_extension()` with a shared
delegate check:

```php
function wp_sqlite_assert_native_parser_delegate( WP_MySQL_Parser $parser, string $context ): void {
    $reflection = new ReflectionObject( $parser );
    if ( ! $reflection->hasProperty( 'native' ) ) {
        wp_sqlite_native_parser_verification_fail( $context );
    }

    $native_property = $reflection->getProperty( 'native' );
    $native_property->setAccessible( true );
    if ( ! ( $native_property->getValue( $parser ) instanceof WP_MySQL_Native_Parser ) ) {
        wp_sqlite_native_parser_verification_fail( $context );
    }
}
```

`WP_SQLITE_REQUIRE_NATIVE_PARSER_EXTENSION=1` in the PHPUnit bootstrap
now loads that verifier instead of inlining the same checks.

`create_parser()` now selects tokens once:

```php
$tokens = $lexer instanceof WP_MySQL_Native_Lexer
    ? $lexer->native_token_stream()
    : $lexer->remaining_tokens();

return $this->reset_or_create_parser( $tokens );
```

The WordPress PHPUnit extension setup keeps its container-specific
verifier, but factors the repeated reflection checks into the same small
helper shape.

## Testing instructions

```bash
cargo fmt --check
bash -n .github/workflows/wp-tests-phpunit-native-extension-setup.sh
node --check .github/workflows/wp-tests-phpunit-run.js
php -l packages/mysql-on-sqlite/tests/tools/verify-native-parser-extension.php
php -l packages/mysql-on-sqlite/tests/bootstrap.php
php ./vendor/bin/phpcs .github/workflows/wp-tests-phpunit-native-extension-setup.sh packages/mysql-on-sqlite/tests/bootstrap.php packages/mysql-on-sqlite/tests/tools/verify-native-parser-extension.php packages/mysql-on-sqlite/src/sqlite/class-wp-pdo-mysql-on-sqlite.php packages/mysql-on-sqlite/tests/mysql/native/WP_MySQL_Native_Parser_Node_Identity_Tests.php packages/mysql-on-sqlite/tests/mysql/native/WP_MySQL_Parser_Instanceof_Tests.php

cd packages/mysql-on-sqlite
php -d extension=../php-ext-wp-mysql-parser/target/debug/libwp_mysql_parser.so tests/tools/verify-native-parser-extension.php
php ./vendor/bin/phpunit -c ./phpunit.xml.dist tests/mysql/native/WP_MySQL_Parser_Instanceof_Tests.php tests/mysql/native/WP_MySQL_Native_Parser_Node_Identity_Tests.php tests/mysql/native/WP_MySQL_Native_Parser_Node_Cycle_Tests.php
WP_SQLITE_REQUIRE_NATIVE_PARSER_EXTENSION=1 php -d extension=../php-ext-wp-mysql-parser/target/debug/libwp_mysql_parser.so ./vendor/bin/phpunit -c ./phpunit.xml.dist --filter 'WP_MySQL_(Native_Parser_Node_(Identity|Cycle)|Parser_Instanceof)_Tests'
php ./vendor/bin/phpunit -c ./phpunit.xml.dist tests/WP_SQLite_Driver_Query_Tests.php
WP_SQLITE_REQUIRE_NATIVE_PARSER_EXTENSION=1 php -d extension=../php-ext-wp-mysql-parser/target/debug/libwp_mysql_parser.so ./vendor/bin/phpunit -c ./phpunit.xml.dist tests/WP_SQLite_Driver_Query_Tests.php
```

CI is passing on `3f4153f`, including the PHP 8.0-8.5 Rust-extension
matrix and `WordPress PHPUnit Tests / Rust extension`.

Author: adamziel

.github/workflows/mysql-parser-extension-tests.yml

@@ -165,91 +165,11 @@ jobs:
         run: cargo build
         working-directory: packages/php-ext-wp-mysql-parser
 
-      - name: Run native parser smoke tests
+      - name: Verify native parser extension
         if: matrix.native
-        run: |
-          php -d extension="$GITHUB_WORKSPACE/packages/php-ext-wp-mysql-parser/target/debug/libwp_mysql_parser.so" -r '
-          require "src/load.php";
-          $lexer = new WP_MySQL_Lexer( "SELECT ID, post_title FROM wp_posts WHERE ID IN (1, 2, 3)" );
-          if ( ! ( $lexer instanceof WP_MySQL_Native_Lexer ) ) {
-              fwrite( STDERR, "Native lexer is not available.\n" );
-              exit( 1 );
-          }
-          $tokens = $lexer->native_token_stream();
-          $rules = include "src/mysql/mysql-grammar.php";
-          $grammar = new WP_Parser_Grammar( $rules );
-          $parser = new WP_MySQL_Parser( $grammar, $tokens );
-          $parser_reflection = new ReflectionObject( $parser );
-          if ( ! $parser_reflection->hasProperty( "native" ) ) {
-              fwrite( STDERR, "WP_MySQL_Parser did not select the native parser delegate.\n" );
-              exit( 1 );
-          }
-          $native_property = $parser_reflection->getProperty( "native" );
-          $native_property->setAccessible( true );
-          if ( ! ( $native_property->getValue( $parser ) instanceof WP_MySQL_Native_Parser ) ) {
-              fwrite( STDERR, "WP_MySQL_Parser did not select the native parser delegate.\n" );
-              exit( 1 );
-          }
-          $ast = $parser->parse();
-          if ( ! $ast instanceof WP_MySQL_Native_Parser_Node || "query" !== $ast->rule_name ) {
-              fwrite( STDERR, "Native parser did not produce the expected query AST.\n" );
-              exit( 1 );
-          }
-          '
+        run: php -d extension="$GITHUB_WORKSPACE/packages/php-ext-wp-mysql-parser/target/debug/libwp_mysql_parser.so" tests/tools/verify-native-parser-extension.php
         working-directory: packages/mysql-on-sqlite
 
-      - name: Verify SQLite driver selects the native parser path
-        if: matrix.native
-        run: |
-          php -d extension="$GITHUB_WORKSPACE/packages/php-ext-wp-mysql-parser/target/debug/libwp_mysql_parser.so" -r '
-          require "packages/mysql-on-sqlite/src/load.php";
-          $lexer = new WP_MySQL_Lexer( "SELECT 1" );
-          if ( ! ( $lexer instanceof WP_MySQL_Native_Lexer ) ) {
-              fwrite( STDERR, "Native lexer is not available.\n" );
-              exit( 1 );
-          }
-          $driver = new WP_PDO_MySQL_On_SQLite( "mysql-on-sqlite:path=:memory:;dbname=wp;" );
-          $parser = $driver->create_parser( "SELECT 1" );
-          $parser_reflection = new ReflectionObject( $parser );
-          if ( ! $parser_reflection->hasProperty( "native" ) ) {
-              fwrite( STDERR, "SQLite driver did not create a native parser delegate.\n" );
-              exit( 1 );
-          }
-          $native_property = $parser_reflection->getProperty( "native" );
-          $native_property->setAccessible( true );
-          if ( ! ( $native_property->getValue( $parser ) instanceof WP_MySQL_Native_Parser ) ) {
-              fwrite( STDERR, "SQLite driver did not create a native parser delegate.\n" );
-              exit( 1 );
-          }
-          $parser->next_query();
-          $ast = $parser->get_query_ast();
-          if ( ! ( $ast instanceof WP_MySQL_Native_Parser_Node ) ) {
-              fwrite( STDERR, "SQLite driver did not return a native-backed AST.\n" );
-              exit( 1 );
-          }
-          $reflection = new ReflectionObject( $ast );
-          if ( $reflection->hasProperty( "native_ast" ) || $reflection->hasProperty( "native_node_index" ) ) {
-              fwrite( STDERR, "Native wrapper still stores Rust AST handle properties.\n" );
-              exit( 1 );
-          }
-          $first = $ast->get_first_child_node();
-          if ( ! ( $first instanceof WP_MySQL_Native_Parser_Node ) ) {
-              fwrite( STDERR, "Native wrapper did not return a native-backed child node.\n" );
-              exit( 1 );
-          }
-          if ( $first !== $ast->get_first_child_node() ) {
-              fwrite( STDERR, "Native wrapper identity is not stable across reads.\n" );
-              exit( 1 );
-          }
-          $synthetic = new WP_Parser_Node( 0, "synthetic" );
-          $first->append_child( $synthetic );
-          $same_first = $ast->get_first_child_node();
-          if ( $same_first !== $first || ! in_array( $synthetic, $same_first->get_children(), true ) ) {
-              fwrite( STDERR, "Materialized native wrapper was lost from the parent cache.\n" );
-              exit( 1 );
-          }
-          '
-
       - name: Run full PHPUnit suite with parser extension
         if: matrix.native
         env:

.github/workflows/wp-tests-phpunit-native-extension-setup.sh

@@ -115,78 +115,69 @@ cat > "$WP_DIR/native-verify-extension.php" <<'EOF'
 <?php
 require_once '/var/www/src/wp-content/plugins/sqlite-database-integration/wp-includes/database/load.php';
 
+function wp_sqlite_native_parser_verification_fail( string $message ): void {
+	fwrite( STDERR, $message . "\n" );
+	exit( 1 );
+}
+
+function wp_sqlite_assert_native_parser_delegate( WP_MySQL_Parser $parser, string $message ): void {
+	$parser_reflection = new ReflectionObject( $parser );
+	if ( ! $parser_reflection->hasProperty( 'native' ) ) {
+		wp_sqlite_native_parser_verification_fail( $message );
+	}
+
+	$native_property = $parser_reflection->getProperty( 'native' );
+	$native_property->setAccessible( true );
+	if ( ! ( $native_property->getValue( $parser ) instanceof WP_MySQL_Native_Parser ) ) {
+		wp_sqlite_native_parser_verification_fail( $message );
+	}
+}
+
 $lexer = new WP_MySQL_Lexer( 'SELECT 1' );
 if ( ! ( $lexer instanceof WP_MySQL_Native_Lexer ) ) {
-	fwrite( STDERR, "Native lexer is not available in the WordPress PHP test container.\n" );
-	exit( 1 );
+	wp_sqlite_native_parser_verification_fail( 'Native lexer is not available in the WordPress PHP test container.' );
 }
 
 $tokens  = $lexer->native_token_stream();
 $rules   = include '/var/www/src/wp-content/plugins/sqlite-database-integration/wp-includes/database/mysql/mysql-grammar.php';
 $grammar = new WP_Parser_Grammar( $rules );
 $parser  = new WP_MySQL_Parser( $grammar, $tokens );
-$parser_reflection = new ReflectionObject( $parser );
-if ( ! $parser_reflection->hasProperty( 'native' ) ) {
-	fwrite( STDERR, "WordPress PHP test container did not select the native parser delegate.\n" );
-	exit( 1 );
-}
-$native_property = $parser_reflection->getProperty( 'native' );
-$native_property->setAccessible( true );
-if ( ! ( $native_property->getValue( $parser ) instanceof WP_MySQL_Native_Parser ) ) {
-	fwrite( STDERR, "WordPress PHP test container did not select the native parser delegate.\n" );
-	exit( 1 );
-}
+wp_sqlite_assert_native_parser_delegate( $parser, 'WordPress PHP test container did not select the native parser delegate.' );
 
 $parser_ast = $parser->parse();
 if ( ! ( $parser_ast instanceof WP_MySQL_Native_Parser_Node ) ) {
-	fwrite( STDERR, "Native parser did not produce a native-backed AST in the WordPress PHP test container.\n" );
-	exit( 1 );
+	wp_sqlite_native_parser_verification_fail( 'Native parser did not produce a native-backed AST in the WordPress PHP test container.' );
 }
 
 $driver = new WP_PDO_MySQL_On_SQLite( 'mysql-on-sqlite:path=:memory:;dbname=wp;' );
 $parser = $driver->create_parser( 'SELECT 1' );
-$parser_reflection = new ReflectionObject( $parser );
-if ( ! $parser_reflection->hasProperty( 'native' ) ) {
-	fwrite( STDERR, "WordPress PHP test container SQLite driver did not create a native parser delegate.\n" );
-	exit( 1 );
-}
-$native_property = $parser_reflection->getProperty( 'native' );
-$native_property->setAccessible( true );
-if ( ! ( $native_property->getValue( $parser ) instanceof WP_MySQL_Native_Parser ) ) {
-	fwrite( STDERR, "WordPress PHP test container SQLite driver did not create a native parser delegate.\n" );
-	exit( 1 );
-}
+wp_sqlite_assert_native_parser_delegate( $parser, 'WordPress PHP test container SQLite driver did not create a native parser delegate.' );
 $parser->next_query();
 $ast = $parser->get_query_ast();
 
 if ( ! ( $ast instanceof WP_MySQL_Native_Parser_Node ) ) {
-	fwrite( STDERR, "WordPress PHP test container did not select the native-backed AST.\n" );
-	exit( 1 );
+	wp_sqlite_native_parser_verification_fail( 'WordPress PHP test container did not select the native-backed AST.' );
 }
 
 $reflection = new ReflectionObject( $ast );
 if ( $reflection->hasProperty( 'native_ast' ) || $reflection->hasProperty( 'native_node_index' ) ) {
-	fwrite( STDERR, "Native wrapper still stores Rust AST handle properties.\n" );
-	exit( 1 );
+	wp_sqlite_native_parser_verification_fail( 'Native wrapper still stores Rust AST handle properties.' );
 }
 
 $first = $ast->get_first_child_node();
 if ( ! ( $first instanceof WP_MySQL_Native_Parser_Node ) ) {
-	fwrite( STDERR, "Native wrapper did not return a native-backed child node.\n" );
-	exit( 1 );
+	wp_sqlite_native_parser_verification_fail( 'Native wrapper did not return a native-backed child node.' );
 }
 
 if ( $first !== $ast->get_first_child_node() ) {
-	fwrite( STDERR, "Native wrapper identity is not stable across reads.\n" );
-	exit( 1 );
+	wp_sqlite_native_parser_verification_fail( 'Native wrapper identity is not stable across reads.' );
 }
 
 $synthetic = new WP_Parser_Node( 0, 'synthetic' );
 $first->append_child( $synthetic );
 $same_first = $ast->get_first_child_node();
 if ( $same_first !== $first || ! in_array( $synthetic, $same_first->get_children(), true ) ) {
-	fwrite( STDERR, "Materialized native wrapper was lost from the parent cache.\n" );
-	exit( 1 );
+	wp_sqlite_native_parser_verification_fail( 'Materialized native wrapper was lost from the parent cache.' );
 }
 EOF
 
@@ -197,7 +188,7 @@ const file = process.argv[2];
 const marker = "require_once ABSPATH . 'wp-settings.php';";
 const guard = [
 	'/*',
-	' * Native parser CI guard. This file is generated by the SQLite integration workflow.',
+	' * Native parser extension guard. This file is generated by the SQLite integration workflow.',
 	' */',
 	"require_once dirname( __DIR__, 3 ) . '/native-verify-extension.php';",
 ].join( '\n' );

.github/workflows/wp-tests-phpunit-run.js

@@ -2,9 +2,8 @@
  * Wrap the "composer run wp-tests-php" command to process tests
  * that are expected to error and fail at the moment.
  *
- * This makes sure that the CI job passes, while explicitly tracking
- * the issues that need to be addressed. Ideally, over time this script
- * will become obsolete when all errors and failures are resolved.
+ * Unexpected errors/failures still fail the workflow. Expected failures that
+ * stop happening are reported so this allowlist can be reduced over time.
  */
 const { execSync } = require( 'child_process' );
 const fs = require( 'fs' );

packages/mysql-on-sqlite/src/sqlite/class-wp-pdo-mysql-on-sqlite.php

@@ -1160,17 +1160,14 @@ public function get_insert_id() {
 	 * @return WP_MySQL_Parser        A parser initialized for the MySQL query.
 	 */
 	public function create_parser( string $query ): WP_MySQL_Parser {
-		$lexer = new WP_MySQL_Lexer(
+		$lexer  = new WP_MySQL_Lexer(
 			$query,
 			80038,
 			$this->active_sql_modes
 		);
-		if ( $lexer instanceof WP_MySQL_Native_Lexer ) {
-			$tokens = $lexer->native_token_stream();
-			return $this->reset_or_create_parser( $tokens );
-		}
-
-		$tokens = $lexer->remaining_tokens();
+		$tokens = $lexer instanceof WP_MySQL_Native_Lexer
+			? $lexer->native_token_stream()
+			: $lexer->remaining_tokens();
 		return $this->reset_or_create_parser( $tokens );
 	}
 

packages/mysql-on-sqlite/tests/bootstrap.php

@@ -10,82 +10,7 @@
 }
 
 if ( '1' === getenv( 'WP_SQLITE_REQUIRE_NATIVE_PARSER_EXTENSION' ) ) {
-	if ( ! class_exists( 'WP_MySQL_Native_Lexer', false ) || ! class_exists( 'WP_MySQL_Native_Parser', false ) ) {
-		fwrite( STDERR, "Native MySQL parser extension is required for this PHPUnit run.\n" );
-		exit( 1 );
-	}
-
-	$native_parser_lexer = new WP_MySQL_Lexer( 'SELECT 1' );
-	if ( ! ( $native_parser_lexer instanceof WP_MySQL_Native_Lexer ) ) {
-		fwrite( STDERR, "WP_MySQL_Lexer did not resolve to the native implementation.\n" );
-		exit( 1 );
-	}
-
-	$native_parser_tokens     = $native_parser_lexer->native_token_stream();
-	$native_parser_rules      = include __DIR__ . '/../src/mysql/mysql-grammar.php';
-	$native_parser_grammar    = new WP_Parser_Grammar( $native_parser_rules );
-	$native_parser            = new WP_MySQL_Parser( $native_parser_grammar, $native_parser_tokens );
-	$native_parser_reflection = new ReflectionObject( $native_parser );
-	if ( ! $native_parser_reflection->hasProperty( 'native' ) ) {
-		fwrite( STDERR, "WP_MySQL_Parser did not create a native parser delegate.\n" );
-		exit( 1 );
-	}
-	$native_parser_property = $native_parser_reflection->getProperty( 'native' );
-	$native_parser_property->setAccessible( true );
-	if ( ! ( $native_parser_property->getValue( $native_parser ) instanceof WP_MySQL_Native_Parser ) ) {
-		fwrite( STDERR, "WP_MySQL_Parser did not create a native parser delegate.\n" );
-		exit( 1 );
-	}
-
-	$native_parser_ast = $native_parser->parse();
-	if ( ! ( $native_parser_ast instanceof WP_MySQL_Native_Parser_Node ) ) {
-		fwrite( STDERR, "Native parser did not produce a native-backed AST.\n" );
-		exit( 1 );
-	}
-
-	$native_parser_driver            = new WP_PDO_MySQL_On_SQLite( 'mysql-on-sqlite:path=:memory:;dbname=wp;' );
-	$native_parser_driver_parser     = $native_parser_driver->create_parser( 'SELECT 1' );
-	$native_parser_driver_reflection = new ReflectionObject( $native_parser_driver_parser );
-	if ( ! $native_parser_driver_reflection->hasProperty( 'native' ) ) {
-		fwrite( STDERR, "WP_PDO_MySQL_On_SQLite did not create a native parser delegate.\n" );
-		exit( 1 );
-	}
-	$native_parser_driver_property = $native_parser_driver_reflection->getProperty( 'native' );
-	$native_parser_driver_property->setAccessible( true );
-	if ( ! ( $native_parser_driver_property->getValue( $native_parser_driver_parser ) instanceof WP_MySQL_Native_Parser ) ) {
-		fwrite( STDERR, "WP_PDO_MySQL_On_SQLite did not create a native parser delegate.\n" );
-		exit( 1 );
-	}
-
-	$native_parser_driver_parser->next_query();
-	$native_parser_driver_ast = $native_parser_driver_parser->get_query_ast();
-	if ( ! ( $native_parser_driver_ast instanceof WP_MySQL_Native_Parser_Node ) ) {
-		fwrite( STDERR, "WP_PDO_MySQL_On_SQLite did not produce a native-backed AST.\n" );
-		exit( 1 );
-	}
-
-	$native_parser_driver_child = $native_parser_driver_ast->get_first_child_node();
-	if ( ! ( $native_parser_driver_child instanceof WP_MySQL_Native_Parser_Node ) ) {
-		fwrite( STDERR, "WP_PDO_MySQL_On_SQLite did not produce native-backed child AST nodes.\n" );
-		exit( 1 );
-	}
-
-	unset(
-		$native_parser_ast,
-		$native_parser,
-		$native_parser_grammar,
-		$native_parser_rules,
-		$native_parser_tokens,
-		$native_parser_lexer,
-		$native_parser_driver,
-		$native_parser_driver_parser,
-		$native_parser_reflection,
-		$native_parser_property,
-		$native_parser_driver_reflection,
-		$native_parser_driver_property,
-		$native_parser_driver_ast,
-		$native_parser_driver_child
-	);
+	require_once __DIR__ . '/tools/verify-native-parser-extension.php';
 }
 
 // Configure the test environment.

packages/mysql-on-sqlite/tests/mysql/native/WP_MySQL_Native_Parser_Node_Identity_Tests.php

@@ -5,13 +5,13 @@
 /**
  * Regression tests for the per-AST identity map on native parser nodes.
  *
- * The native extension constructs a fresh PHP wrapper for every accessor
- * call. Without interning, two reads of the same logical node would yield
- * distinct objects, and a mutation made through a still-live wrapper would be
- * invisible through the second. WP_Parser_Node exposes public mutators and
- * stable child identity, so the native wrapper must preserve both.
+ * The native extension materializes PHP wrappers from Rust-owned arena nodes.
+ * Without interning, two reads of the same logical node would yield distinct
+ * objects, and a mutation made through a still-live wrapper would be invisible
+ * through the second. WP_Parser_Node exposes public mutators and stable child
+ * identity, so the native wrapper must preserve both.
  *
- * Skipped when the native extension is not loaded — the pure-PHP code
+ * Skipped when the native extension is not loaded; the pure-PHP code
  * path already has stable identity by construction.
  */
 class WP_MySQL_Native_Parser_Node_Identity_Tests extends TestCase {
@@ -96,11 +96,9 @@ public function test_mutation_on_child_survives_re_read(): void {
 		$child = $tree->get_first_child_node();
 		$this->assertNotNull( $child );
 
-		// Mutate via the public WP_Parser_Node API — this is exactly the
-		// kind of state the reviewer worried would be lost when accessors
-		// hand back fresh wrappers. rule_name is a declared public property
-		// that the parser itself sets, so PHP 8.2's dynamic-property
-		// deprecation does not apply here.
+		// Mutate via the public WP_Parser_Node API. This catches regressions
+		// where accessors hand back fresh wrappers and lose state written
+		// through a previously returned child.
 		$child->rule_name = 'mutated-rule';
 
 		$same_child = $tree->get_first_child_node();

packages/mysql-on-sqlite/tests/mysql/native/WP_MySQL_Parser_Instanceof_Tests.php

@@ -5,11 +5,10 @@
 /**
  * `WP_MySQL_Parser instanceof WP_Parser` must hold in both modes.
  *
- * Pre-PR, the native-mode `WP_MySQL_Parser` was `extends WP_MySQL_Native_Parser`
- * (a Rust-registered class with no `WP_Parser` in its chain), so existing
- * downstream code doing `if ($parser instanceof WP_Parser)` silently
- * skipped the parser when the extension was loaded. This test pins the
- * contract for both modes.
+ * The native-mode `WP_MySQL_Parser` must not expose the Rust-registered
+ * parser directly. Existing downstream code may rely on
+ * `if ($parser instanceof WP_Parser)`, so this test pins the contract for
+ * both modes.
  */
 class WP_MySQL_Parser_Instanceof_Tests extends TestCase {