fix: preserve native transaction and lock semantics

inc/native/class-wp-markdown-native-advisory-locks.php

@@ -0,0 +1,90 @@
+<?php
+/** Root-scoped, process-safe named locks for the native MySQL compatibility layer. */
+
+if ( ! defined( 'ABSPATH' ) ) {
+	exit;
+}
+
+final class WP_Markdown_Native_Advisory_Locks {
+
+	private const DIRECTORY = '_locks';
+	/** The largest ordinary consumer lock wait accepted by the native runtime. */
+	public const MAX_WAIT_SECONDS = 10.0;
+
+	/** @var array<string,array{handle:resource,count:int,path:string}> */
+	private array $locks = array();
+
+	public function __construct( private readonly string $state_root ) {}
+
+	/** Acquire a named lock, waiting no longer than the requested bounded timeout. */
+	public function acquire( string $name, float $timeout ): bool {
+		if ( isset( $this->locks[ $name ] ) ) {
+			++$this->locks[ $name ]['count'];
+			return true;
+		}
+		$directory = $this->state_root . DIRECTORY_SEPARATOR . self::DIRECTORY;
+		if ( ! is_dir( $directory ) && ! @mkdir( $directory, 0755, true ) && ! is_dir( $directory ) ) {
+			return false;
+		}
+		$path = $directory . DIRECTORY_SEPARATOR . hash( 'sha256', $name ) . '.lock';
+		$handle = @fopen( $path, 'c+b' );
+		if ( false === $handle ) {
+			return false;
+		}
+		$wait = $timeout * 1000000;
+		$deadline = hrtime( true ) + (int) ( $wait * 1000 );
+		do {
+			if ( flock( $handle, LOCK_EX | LOCK_NB ) ) {
+				$this->locks[ $name ] = array( 'handle' => $handle, 'count' => 1, 'path' => $path );
+				return true;
+			}
+			if ( 0.0 === $wait || hrtime( true ) >= $deadline ) {
+				break;
+			}
+			usleep( 10000 );
+		} while ( true );
+		fclose( $handle );
+		return false;
+	}
+
+	/** @return int|null One when released, zero when held by another connection, null when absent. */
+	public function release( string $name ): ?int {
+		if ( ! isset( $this->locks[ $name ] ) ) {
+			$handle = @fopen( $this->path( $name ), 'c+b' );
+			if ( false === $handle ) {
+				return null;
+			}
+			$available = flock( $handle, LOCK_EX | LOCK_NB );
+			if ( $available ) {
+				flock( $handle, LOCK_UN );
+			}
+			fclose( $handle );
+			return $available ? null : 0;
+		}
+		--$this->locks[ $name ]['count'];
+		if ( 0 < $this->locks[ $name ]['count'] ) {
+			return 1;
+		}
+		$lock = $this->locks[ $name ];
+		unset( $this->locks[ $name ] );
+		flock( $lock['handle'], LOCK_UN );
+		fclose( $lock['handle'] );
+		return 1;
+	}
+
+	/** Release every lock when the logical native connection closes. */
+	public function close(): void {
+		foreach ( array_keys( $this->locks ) as $name ) {
+			$this->locks[ $name ]['count'] = 1;
+			$this->release( $name );
+		}
+	}
+
+	public function __destruct() {
+		$this->close();
+	}
+
+	private function path( string $name ): string {
+		return $this->state_root . DIRECTORY_SEPARATOR . self::DIRECTORY . DIRECTORY_SEPARATOR . hash( 'sha256', $name ) . '.lock';
+	}
+}

inc/native/class-wp-markdown-native-option-mutations.php

@@ -10,7 +10,9 @@ final class WP_Markdown_Native_Option_Mutation {
 	public function __construct(
 		private readonly string $operation,
 		private readonly string $option_name,
-		private readonly array $values
+		private readonly array $values,
+		private readonly ?string $expected_option_value = null,
+		private readonly bool $expected_option_value_is_binary = false
 	) {
 		if ( ! in_array( $operation, array( 'insert', 'upsert', 'update', 'delete' ), true ) ) {
 			throw new InvalidArgumentException( 'Unsupported option mutation operation.' );
@@ -37,6 +39,14 @@ public function option_name(): string {
 	public function values(): array {
 		return $this->values;
 	}
+
+	public function expected_option_value(): ?string {
+		return $this->expected_option_value;
+	}
+
+	public function expected_option_value_is_binary(): bool {
+		return $this->expected_option_value_is_binary;
+	}
 }
 
 final class WP_Markdown_Native_Option_Mutation_Parser {
@@ -168,8 +178,22 @@ private function parse_update( WP_Markdown_Query_Request $request ): WP_Markdown
 		}
 		$this->type( WP_Markdown_Native_SQL_Token::EQUALS );
 		$option_name = (string) $this->type( WP_Markdown_Native_SQL_Token::STRING )->value();
+		$expected_option_value = null;
+		$expected_option_value_is_binary = false;
+		if ( 0 === strcasecmp( 'AND', (string) $this->current()->value() ) ) {
+			++$this->position;
+			if ( 0 === strcasecmp( 'BINARY', (string) $this->current()->value() ) ) {
+				++$this->position;
+				$expected_option_value_is_binary = true;
+			}
+			if ( 'option_value' !== $this->identifier() ) {
+				return $this->failure( 'unsupported_option_update', 'mdi-native option updates may condition only on the current option value.' );
+			}
+			$this->type( WP_Markdown_Native_SQL_Token::EQUALS );
+			$expected_option_value = (string) $this->type( WP_Markdown_Native_SQL_Token::STRING )->value();
+		}
 		$this->type( WP_Markdown_Native_SQL_Token::END );
-		return new WP_Markdown_Native_Option_Mutation( 'update', $option_name, $changes );
+		return new WP_Markdown_Native_Option_Mutation( 'update', $option_name, $changes, $expected_option_value, $expected_option_value_is_binary );
 	}
 
 	private function parse_delete( WP_Markdown_Query_Request $request ): WP_Markdown_Native_Option_Mutation|WP_Markdown_Query_Result {
@@ -388,6 +412,17 @@ private function mutate( WP_Markdown_Native_Option_Mutation $mutation ): WP_Mark
 			if ( $mutation->is_insert() && null !== $existing ) {
 				return $this->failure( 'duplicate_key', 'The canonical option identity already exists.' );
 			}
+			if ( null !== $mutation->expected_option_value() ) {
+				if ( $mutation->expected_option_value_is_binary() ) {
+					if ( $mutation->expected_option_value() !== $existing['row']['option_value'] ) {
+						return WP_Markdown_Query_Result::mutated( 0 );
+					}
+				} elseif ( null === $this->schema->value_key( 'option_value', $mutation->expected_option_value() ) || null === $this->schema->value_key( 'option_value', $existing['row']['option_value'] ) ) {
+					return $this->failure( 'unsupported_option_collation', 'The option mutation requires an unsupported option-value collation.' );
+				} elseif ( ! $this->schema->values_match( 'option_value', $mutation->expected_option_value(), $existing['row']['option_value'] ) ) {
+					return WP_Markdown_Query_Result::mutated( 0 );
+				}
+			}
 			if ( $mutation->is_delete() ) {
 				$journaled = $this->journal( $existing['path'] );
 				if ( true !== $journaled ) {

inc/native/class-wp-markdown-native-query-executor.php

@@ -50,7 +50,8 @@ public function __construct(
 		private ?WP_Markdown_Native_Table_Mutation_Runtime $table_mutations = null,
 		private ?WP_Markdown_Native_Transaction_Journal $transactions = null,
 		private ?WP_Markdown_Native_Post_Mutation_Runtime $post_mutations = null,
-		private int $correlated_subquery_limit = self::MAX_CORRELATED_SUBQUERY_EVALUATIONS
+		private int $correlated_subquery_limit = self::MAX_CORRELATED_SUBQUERY_EVALUATIONS,
+		private ?WP_Markdown_Native_Advisory_Locks $advisory_locks = null
 	) {
 		$this->schema_introspection = new WP_Markdown_Native_Schema_Introspection( $registry );
 	}
@@ -63,6 +64,10 @@ public function execute( WP_Markdown_Query_Request $request ): WP_Markdown_Query
 		if ( 1 === preg_match( '/^\s*(?:SHOW|DESCRIBE)\b/i', $request->sql() ) ) {
 			return $this->schema_introspection->execute( $request );
 		}
+		$advisory_lock = $this->advisory_lock_query( $request->sql() );
+		if ( null !== $advisory_lock ) {
+			return $advisory_lock;
+		}
 		// The canonical store is a directory, not a named server database.
 		if ( 1 === preg_match( '/^\s*SELECT\s+DATABASE\s*\(\s*\)\s*;?\s*$/i', $request->sql() ) ) {
 			return WP_Markdown_Query_Result::selected(
@@ -116,6 +121,38 @@ public function execute( WP_Markdown_Query_Request $request ): WP_Markdown_Query
 		return $this->execute_plan( $plan );
 	}
 
+	/** Release this logical connection's root-scoped advisory locks. */
+	public function close(): void {
+		$this->advisory_locks?->close();
+	}
+
+	private function advisory_lock_query( string $sql ): ?WP_Markdown_Query_Result {
+		if ( 1 !== preg_match( "/^\\s*SELECT\\s+((GET_LOCK|RELEASE_LOCK)\\s*\\(\\s*('(?:\\\\.|[^'])*')\\s*(?:,\\s*([0-9]+(?:\\.[0-9]+)?))?\\s*\\))\\s*;?\\s*$/i", $sql, $match ) ) {
+			return null;
+		}
+		$function = strtoupper( $match[2] );
+		if ( ( 'GET_LOCK' === $function && ! isset( $match[4] ) ) || ( 'RELEASE_LOCK' === $function && isset( $match[4] ) ) || null === $this->advisory_locks ) {
+			return $this->failure( 'unsupported_grammar', 'mdi-native advisory locks require a literal name and bounded timeout.' );
+		}
+		try {
+			$literal = ( new WP_Markdown_Native_SQL_Tokenizer() )->tokenize( $match[3] )[0];
+			$name = $literal->value();
+		} catch ( WP_Markdown_Native_SQL_Parse_Error ) {
+			return $this->failure( 'unsupported_literal', 'mdi-native cannot decode the requested advisory lock name.' );
+		}
+		if ( ! is_string( $name ) || ( isset( $match[4] ) && (float) $match[4] > WP_Markdown_Native_Advisory_Locks::MAX_WAIT_SECONDS ) ) {
+			return $this->failure( 'unsupported_grammar', 'mdi-native advisory lock timeouts must be between 0 and 10 seconds.' );
+		}
+		$value = 'GET_LOCK' === $function
+			? (int) $this->advisory_locks->acquire( $name, (float) $match[4] )
+			: $this->advisory_locks->release( $name );
+		$column = $match[1];
+		return WP_Markdown_Query_Result::selected(
+			array( array( $column => null === $value ? null : (string) $value ) ),
+			array( array( 'name' => $column, 'table' => '', 'type' => 8 ) )
+		);
+	}
+
 	private function execute_plan( WP_Markdown_Native_Query_Plan $plan, bool $allow_union = true ): WP_Markdown_Query_Result {
 		if ( $allow_union && null !== $plan->union() ) {
 			return $this->execute_union( $plan );

inc/native/class-wp-markdown-native-query-runtime.php

@@ -23,6 +23,7 @@
 require_once __DIR__ . '/../class-wp-markdown-sql-classifier.php';
 require_once __DIR__ . '/../class-wp-markdown-table-durability-policy.php';
 require_once __DIR__ . '/class-wp-markdown-native-transactions.php';
+require_once __DIR__ . '/class-wp-markdown-native-advisory-locks.php';
 require_once __DIR__ . '/class-wp-markdown-native-query-executor.php';
 
 final class WP_Markdown_Native_Runtime_Factory {
@@ -38,6 +39,10 @@ public static function options_schema(): WP_Markdown_Native_Table_Schema {
 						'lookup_operators' => array( '=', 'IN' ),
 						'lookup_validator' => static fn( array $values ): bool => self::all_ascii_strings( $values ),
 					),
+					// WordPress options use a nonbinary text column. Limit native CAS
+					// matching to the ASCII portion of that collation rather than guess
+					// at an unsupported Unicode collation.
+					'option_value' => array( 'normalizer' => array( self::class, 'normalize_ascii_ci_padded' ) ),
 					'autoload' => array(
 						'lookup_operators' => array( 'IN' ),
 						'lookup_validator' => static fn( array $values ): bool => ! array_diff( $values, array( 'yes', 'on', 'auto-on', 'auto' ) ),
@@ -229,7 +234,8 @@ public static function runtime(
 		bool $multisite = false,
 		?string $content_root = null,
 		?string $global_state_root = null,
-		?string $global_content_root = null
+		?string $global_content_root = null,
+		?WP_Markdown_Native_Advisory_Locks $advisory_locks = null
 	): WP_Markdown_Native_Query_Runtime {
 		$state_root = self::materialize_state_root( $state_root );
 		if ( null !== $global_state_root ) {
@@ -265,7 +271,8 @@ public static function runtime(
 				$parser,
 				self::shared_storage( $content_root ?? $state_root ),
 				$transactions
-			)
+			),
+			advisory_locks: $advisory_locks ?? new WP_Markdown_Native_Advisory_Locks( $state_root )
 		);
 	}
 
@@ -549,6 +556,11 @@ public static function normalize_ascii_ci( mixed $value ): ?string {
 		return strtolower( $value );
 	}
 
+	public static function normalize_ascii_ci_padded( mixed $value ): ?string {
+		$value = self::normalize_ascii_ci( $value );
+		return null === $value ? null : rtrim( $value, ' ' );
+	}
+
 	private static function all_normalized_unsigned( array $values ): bool {
 		foreach ( $values as $value ) {
 			if ( null === self::normalize_unsigned( $value ) ) {
@@ -598,11 +610,14 @@ final class WP_Markdown_Native_Prefix_Query_Runtime implements WP_Markdown_Query
 
 	/** @var array<string,WP_Markdown_Native_Query_Runtime> */
 	private array $runtimes = array();
+	private WP_Markdown_Native_Advisory_Locks $advisory_locks;
 
 	public function __construct(
 		private string $state_root,
 		private string $content_root
-	) {}
+	) {
+		$this->advisory_locks = new WP_Markdown_Native_Advisory_Locks( $state_root );
+	}
 
 	public function execute( WP_Markdown_Query_Request $request ): WP_Markdown_Query_Result {
 		$prefix = $request->table_prefix();
@@ -612,11 +627,16 @@ public function execute( WP_Markdown_Query_Request $request ): WP_Markdown_Query
 				$prefix,
 				$prefix,
 				false,
-				$this->content_root
+				$this->content_root,
+				advisory_locks: $this->advisory_locks
 			);
 		}
 		return $this->runtimes[ $prefix ]->execute( $request );
 	}
+
+	public function close(): void {
+		$this->advisory_locks->close();
+	}
 }
 
 /** Defer WordPress topology detection because db.php precedes multisite bootstrap. */
@@ -648,6 +668,13 @@ public function execute( WP_Markdown_Query_Request $request ): WP_Markdown_Query
 		}
 		return $this->multisite_runtimes[ $base_prefix ]->execute( $request );
 	}
+
+	public function close(): void {
+		$this->prefix_runtime->close();
+		foreach ( $this->multisite_runtimes as $runtime ) {
+			$runtime->close();
+		}
+	}
 }
 
 /** Lazily compose a native runtime for each WordPress multisite table scope. */
@@ -657,6 +684,7 @@ final class WP_Markdown_Native_Multisite_Query_Runtime implements WP_Markdown_Qu
 	private array $runtimes = array();
 	private string $state_root;
 	private string $content_root;
+	private WP_Markdown_Native_Advisory_Locks $advisory_locks;
 
 	public function __construct(
 		string $state_root,
@@ -668,6 +696,7 @@ public function __construct(
 		}
 		$this->state_root = rtrim( $state_root, '/\\' );
 		$this->content_root = rtrim( $content_root, '/\\' );
+		$this->advisory_locks = new WP_Markdown_Native_Advisory_Locks( $this->state_root );
 	}
 
 	public function execute( WP_Markdown_Query_Request $request ): WP_Markdown_Query_Result {
@@ -700,7 +729,8 @@ public function execute( WP_Markdown_Query_Request $request ): WP_Markdown_Query
 					true,
 					$roots['content'],
 					$this->state_root,
-					$this->content_root
+					$this->content_root,
+					$this->advisory_locks
 				);
 			} catch ( Throwable ) {
 				return WP_Markdown_Query_Result::failure(
@@ -715,6 +745,10 @@ public function execute( WP_Markdown_Query_Request $request ): WP_Markdown_Query
 		return $this->runtimes[ $prefix ]->execute( $request );
 	}
 
+	public function close(): void {
+		$this->advisory_locks->close();
+	}
+
 	private function is_scope_prefix( string $prefix ): bool {
 		if ( $this->base_prefix === $prefix || ! str_starts_with( $prefix, $this->base_prefix ) ) {
 			return $this->base_prefix === $prefix;

inc/native/class-wp-markdown-native-transactions.php

@@ -220,19 +220,24 @@ public function rollback(): true|string {
 
 	public function savepoint( string $name ): true|string {
 		if ( ! $this->active ) {
-			$begun = $this->begin();
-			if ( true !== $begun ) {
-				return $begun;
+			// With autocommit on, MySQL accepts SAVEPOINT without opening a transaction.
+			if ( $this->autocommit ) {
+				return true;
 			}
+			$this->savepoints[ $name ] = 0;
+			return true;
 		}
 		$this->savepoints[ $name ] = count( $this->entries );
 		return true;
 	}
 
 	public function rollback_to( string $name ): true|string {
-		if ( ! $this->active || ! isset( $this->savepoints[ $name ] ) ) {
+		if ( ! isset( $this->savepoints[ $name ] ) || ( ! $this->active && $this->autocommit ) ) {
 			return sprintf( 'SAVEPOINT %s does not exist.', $name );
 		}
+		if ( ! $this->active ) {
+			return true;
+		}
 		$marker   = $this->savepoints[ $name ];
 		$restored = $this->restore( $this->entries, $marker );
 		if ( true !== $restored ) {
@@ -248,9 +253,13 @@ public function rollback_to( string $name ): true|string {
 	}
 
 	public function release_savepoint( string $name ): true|string {
-		if ( ! $this->active || ! isset( $this->savepoints[ $name ] ) ) {
+		if ( ! isset( $this->savepoints[ $name ] ) || ( ! $this->active && $this->autocommit ) ) {
 			return sprintf( 'SAVEPOINT %s does not exist.', $name );
 		}
+		if ( ! $this->active ) {
+			unset( $this->savepoints[ $name ] );
+			return true;
+		}
 		$marker = $this->savepoints[ $name ];
 		foreach ( $this->savepoints as $savepoint => $offset ) {
 			if ( $offset >= $marker ) {