Fix column default value handling

Author: JanJakes

tests/WP_SQLite_Driver_Tests.php

@@ -476,7 +476,7 @@ public function testShowCreateTableWithCorrectDefaultValues() {
 			'CREATE TABLE `_tmp__table` (
   `ID` bigint NOT NULL AUTO_INCREMENT,
   `default_empty_string` varchar(255) DEFAULT \'\',
-  `null_no_default` varchar(255),
+  `null_no_default` varchar(255) DEFAULT NULL,
   PRIMARY KEY (`ID`)
 ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_general_ci',
 			$results[0]->{'Create Table'}
@@ -1954,7 +1954,7 @@ public function testAlterTableModifyColumnWithHyphens() {
 					'Type'    => 'text',
 					'Null'    => 'YES',
 					'Key'     => '',
-					'Default' => 'NULL',
+					'Default' => null,
 					'Extra'   => '',
 				),
 			),
@@ -3384,7 +3384,7 @@ public function testUniqueConstraints() {
 	public function testDefaultNullValue() {
 		$this->assertQuery(
 			'CREATE TABLE _tmp_table (
-				name varchar(20) NOT NULL default NULL,
+				name varchar(20) default NULL,
 				no_default varchar(20) NOT NULL
 			);'
 		);
@@ -3397,9 +3397,9 @@ public function testDefaultNullValue() {
 				(object) array(
 					'Field'   => 'name',
 					'Type'    => 'varchar(20)',
-					'Null'    => 'NO',
+					'Null'    => 'YES',
 					'Key'     => '',
-					'Default' => 'NULL',
+					'Default' => null,
 					'Extra'   => '',
 				),
 				(object) array(

wp-includes/sqlite-ast/class-wp-sqlite-driver.php

@@ -2181,8 +2181,18 @@ private function get_sqlite_create_table_statement( string $table_name, ?string
 				$query            .= ' PRIMARY KEY AUTOINCREMENT';
 			}
 			if ( null !== $column['COLUMN_DEFAULT'] ) {
-				// @TODO: Correctly quote based on the data type.
-				$query .= ' DEFAULT ' . $this->pdo->quote( $column['COLUMN_DEFAULT'] );
+				// @TODO: Handle defaults with expression values (DEFAULT_GENERATED).
+
+				// Handle DEFAULT CURRENT_TIMESTAMP. This works only with timestamp
+				// and datetime columns. For other column types, it's just a string.
+				if (
+					'CURRENT_TIMESTAMP' === $column['COLUMN_DEFAULT']
+					&& ( 'timestamp' === $column['DATA_TYPE'] || 'datetime' === $column['DATA_TYPE'] )
+				) {
+					$query .= ' DEFAULT CURRENT_TIMESTAMP';
+				} else {
+					$query .= ' DEFAULT ' . $this->pdo->quote( $column['COLUMN_DEFAULT'] );
+				}
 			}
 			$rows[] = $query;
 
@@ -2304,9 +2314,18 @@ private function get_mysql_create_table_statement( string $table_name ): ?string
 			if ( 'auto_increment' === $column['EXTRA'] ) {
 				$sql .= ' AUTO_INCREMENT';
 			}
-			if ( null !== $column['COLUMN_DEFAULT'] ) {
-				// @TODO: Correctly quote based on the data type.
+
+			// Handle DEFAULT CURRENT_TIMESTAMP. This works only with timestamp
+			// and datetime columns. For other column types, it's just a string.
+			if (
+				'CURRENT_TIMESTAMP' === $column['COLUMN_DEFAULT']
+				&& ( 'timestamp' === $column['DATA_TYPE'] || 'datetime' === $column['DATA_TYPE'] )
+			) {
+				$sql .= ' DEFAULT CURRENT_TIMESTAMP';
+			} elseif ( null !== $column['COLUMN_DEFAULT'] ) {
 				$sql .= ' DEFAULT ' . $this->pdo->quote( $column['COLUMN_DEFAULT'] );
+			} elseif ( 'YES' === $column['IS_NULLABLE'] ) {
+				$sql .= ' DEFAULT NULL';
 			}
 			$rows[] = $sql;
 		}

wp-includes/sqlite-ast/class-wp-sqlite-information-schema-builder.php

@@ -905,14 +905,31 @@ private function get_table_collation( WP_Parser_Node $node ): string {
 	}
 
 	private function get_column_default( WP_Parser_Node $node ): ?string {
+		$default_attr = null;
 		foreach ( $node->get_descendant_nodes( 'columnAttribute' ) as $attr ) {
 			if ( $attr->has_child_token( WP_MySQL_Lexer::DEFAULT_SYMBOL ) ) {
-				// @TODO: MySQL seems to normalize default values for numeric
-				//        columns, such as 1.0 to 1, 1e3 to 1000, etc.
-				return substr( $this->get_value( $attr ), strlen( 'DEFAULT' ) );
+				$default_attr = $attr;
 			}
 		}
-		return null;
+
+		if ( null === $default_attr ) {
+			return null;
+		}
+
+		if ( $default_attr->has_child_token( WP_MySQL_Lexer::NOW_SYMBOL ) ) {
+			return 'CURRENT_TIMESTAMP';
+		}
+
+		if (
+			$default_attr->has_child_node( 'signedLiteral' )
+			&& null !== $default_attr->get_descendant_node( 'nullLiteral' )
+		) {
+			return null;
+		}
+
+		// @TODO: MySQL seems to normalize default values for numeric
+		//        columns, such as 1.0 to 1, 1e3 to 1000, etc.
+		return $this->get_value( $default_attr->get_child_node() );
 	}
 
 	private function get_column_nullable( WP_Parser_Node $node ): string {
@@ -967,32 +984,43 @@ private function get_column_key( WP_Parser_Node $column_node ): string {
 	}
 
 	private function get_column_extra( WP_Parser_Node $node ): string {
-		$extra = '';
+		$extras     = array();
+		$attributes = $node->get_descendant_nodes( 'columnAttribute' );
 
 		// SERIAL
 		$data_type = $node->get_descendant_node( 'dataType' );
 		if ( null !== $data_type->get_descendant_token( WP_MySQL_Lexer::SERIAL_SYMBOL ) ) {
 			return 'auto_increment';
 		}
 
-		foreach ( $node->get_descendant_nodes( 'columnAttribute' ) as $attr ) {
+		// Check whether DEFAULT value is an expression.
+		foreach ( $attributes as $attr ) {
+			if (
+				$attr->has_child_token( WP_MySQL_Lexer::DEFAULT_SYMBOL )
+				&& $attr->has_child_node( 'exprWithParentheses' )
+			) {
+				$extras[] = 'DEFAULT_GENERATED';
+			}
+		}
+
+		foreach ( $attributes as $attr ) {
 			if ( $attr->has_child_token( WP_MySQL_Lexer::AUTO_INCREMENT_SYMBOL ) ) {
 				return 'auto_increment';
 			}
 			if (
 				$attr->has_child_token( WP_MySQL_Lexer::ON_SYMBOL )
 				&& $attr->has_child_token( WP_MySQL_Lexer::UPDATE_SYMBOL )
 			) {
-				return 'on update CURRENT_TIMESTAMP';
+				$extras[] = 'on update CURRENT_TIMESTAMP';
 			}
 		}
 
 		if ( $node->get_descendant_token( WP_MySQL_Lexer::VIRTUAL_SYMBOL ) ) {
-			$extra = 'VIRTUAL GENERATED';
+			$extras[] = 'VIRTUAL GENERATED';
 		} elseif ( $node->get_descendant_token( WP_MySQL_Lexer::STORED_SYMBOL ) ) {
-			$extra = 'STORED GENERATED';
+			$extras[] = 'STORED GENERATED';
 		}
-		return $extra;
+		return implode( ' ', $extras );
 	}
 
 	private function get_column_comment( WP_Parser_Node $node ): string {