WordPress Importer: line-ending mismatch corrupts serialized meta

[WraithKenny]

A possible solution:

if ( $key ) {
	// export gets meta straight from the DB so could have a serialized string
	if ( ! $value )
		$value = maybe_unserialize( $meta['value'] );
	// Occationally, line-endings break unserialize()
	if ( empty( $value ) ) // Try normalizing...
		$value = maybe_unserialize( str_replace( array("\r\n", "\r", "\n"), "\r\n", $meta['value'] ) );
	if ( empty( $value ) ) // Adjust string length if needed
		$value = maybe_unserialize(
			preg_replace( // e flag deprecated in PHP 5.5.0 I think
				'!s:(\d+):"(.*?)";!se',
				"'s:'.strlen('$2').':\"$2\";'",
				$meta['value']
			)
		);

	add_post_meta( $post_id, $key, $value );
	do_action( 'import_post_meta', $post_id, $key, $value );

	// if the post has a featured image, take note of this in case of remap
	if ( '_thumbnail_id' == $key )
		$this->featured_images[$post_id] = (int) $value;
}

[johnbillion]

Are you able to submit this as a patch Kenny? Or a pointer to which file and line it affects. A little more detail would be good too, such as what the problem is exactly and what this is fixing.

[WraithKenny]

The issue:

I've noticed that on some installs (xampp, mampp) the parsing of the import file into php, and then the attempt to unserialize fails do to line-ending mismatches. This patch attempts to normalize the line-endings if first pass fails, and adjusts the s-length if the second pass fails.

Alternatively, finding out which step causes the line-endings to change/conflict and preventing it there might be a better/cleaner solution, but that might be with how plugins store meta_data. My own plugin seems to save different endings via html post or ajax save. It doesn't effect the functioning of the plugin tho, only the importing of the meta_data. This should be fine anyway, except that when the file is saved (either by the browser, or up to the server or when the file is processed), then line-endings change, corrupting data or the s:length.

The patch was what I could get working.

[WraithKenny]

It just occurred to me that git might have altered the import file, but I'm fairly certain I also tested fresh export files that didn't go through git. Since this just occurred to me I haven't tested thoroughly.

[jjeaton]

I just ran into this issue. A mismatch wasn't the problem for me, but having any windows line endings inside a serialized array (even without any other types of line endings).

This appears to be a PHP bug first filed in 2008: ​https://bugs.php.net/bug.php?id=45573&edit=3. I'm not sure why it never got any attention.

I can reproduce it here: ​Test case in a PHP Repl

[netweb]

Replying to jjeaton:

I can reproduce it here: ​Test case in a PHP Repl

Perfect excuse to test some code in all the PHP versions ​http://3v4l.org/X0pFQ

[xjsv]

It seems like the PHP issue has been closed as "Not a Bug" as of 2016-07-26.