Script output for preview is not being marked as dev mode creating validation error

[milindmore22]

Bug Description

A user reported that the wp_post_preview_js is creating a validation error, we have marked that as dev mode but it seems some recent changes made the XPath invalid. creating validation error.

I was able to reproduce the error on my test site.

Preview Script.

{
	"node_name": "script",
	"parent_name": "head",
	"code": "DISALLOWED_TAG",
	"type": "js_error",
	"node_attributes": [],
	"text": "\n\t( function() {\n\t\tvar query = document.location.search;\n\n\t\tif ( query && query.indexOf( __SINGLE_QUOTED_STRING__ ) !== __INT__ ) {\n\t\t\twindow.name = __SINGLE_QUOTED_STRING__;\n\t\t}\n\n\t\tif ( window.addEventListener ) {\n\t\t\twindow.addEventListener( __SINGLE_QUOTED_STRING__, function() { window.name = __SINGLE_QUOTED_STRING__; } );\n\t\t}\n\t}());\n\t\n",
	"node_type": "ELEMENT",
	"sources": [
		{
			"type": "core",
			"name": "wp-includes",
			"file": "functions.php",
			"line": 7596,
			"function": "wp_post_preview_js",
			"hook": "wp_head",
			"priority": 1
		}
	],
	"removed": true,
	"reviewed": false
}

{
	"node_name": "script",
	"parent_name": "head",
	"code": "DISALLOWED_TAG",
	"type": "js_error",
	"node_attributes": {
		"type": "text/javascript"
	},
	"text": "\n   (function(m,e,t,r,i,k,a){m[i]=m[i]||function(){(m[i].a=m[i].a||[]).push(arguments)};\n   m[i].l=__INT__*new Date();\n   for (var j = __INT__; j < document.scripts.length; j++) {if (document.scripts[j].src === r) { return; }}\n   k=e.createElement(t),a=e.getElementsByTagName(t)[__INT__],k.async=__INT__,k.src=r,a.parentNode.insertBefore(k,a)})\n   (window, document, __DOUBLE_QUOTED_STRING__, __DOUBLE_QUOTED_STRING__, __DOUBLE_QUOTED_STRING__);\n\n   ym(__INT__, __DOUBLE_QUOTED_STRING__, {\n        clickmap:true,\n        trackLinks:true,\n        accurateTrackBounce:true\n   });\n",
	"node_type": "ELEMENT",
	"sources": [
		{
			"type": "theme",
			"name": "twentytwentyone",
			"file": "functions.php",
			"line": 657,
			"function": "{closure}",
			"hook": "wp_head",
			"priority": 10
		}
	],
	"removed": true,
	"reviewed": false
}

Expected Behaviour

There should not be validation error

Screenshots

No response

PHP Version

No response

Plugin Version

2.5.2

AMP plugin template mode

Transitional

WordPress Version

No response

Site Health

No response

Gutenberg Version

No response

OS(s) Affected

No response

Browser(s) Affected

No response

Device(s) Affected

No response

Acceptance Criteria

No response

Implementation Brief

No response

QA Testing Instructions

No response

Demo

No response

Changelog Entry

No response

[westonruter]

This is the plugin code in question:

amp-wp/includes/amp-helper-functions.php

Lines 1652 to 1658 in 2efb5c8

	// Mark the script output by wp_post_preview_js() as being in dev mode.
	if ( is_preview() && get_queried_object() instanceof WP_Post ) {
	$dev_mode_xpaths[] = sprintf(
	'//script[ not( @src ) and contains( text(), "document.location.search" ) and contains( text(), "preview=true" ) and contains( text(), "unload" ) and contains( text(), "window.name" ) and contains( text(), "wp-preview-%d" ) ]',
	get_queried_object_id()
	);
	}

And here is the function code:

function wp_post_preview_js() {
	global $post;

	if ( ! is_preview() || empty( $post ) ) {
		return;
	}

	// Has to match the window name used in post_submit_meta_box().
	$name = 'wp-preview-' . (int) $post->ID;

	ob_start();
	?>
	<script>
	( function() {
		var query = document.location.search;

		if ( query && query.indexOf( 'preview=true' ) !== -1 ) {
			window.name = '<?php echo $name; ?>';
		}

		if ( window.addEventListener ) {
			window.addEventListener( 'pagehide', function() { window.name = ''; } );
		}
	}());
	</script>
	<?php
	wp_print_inline_script_tag( wp_remove_surrounding_empty_script_tags( ob_get_clean() ) );
}

The problem is contains( text(), "unload" ) in the XPath. Somebody replaced unload with pagehide in WordPress/wordpress-develop@fbe3732.

So I suggest this fix:

- '//script[ not( @src ) and contains( text(), "document.location.search" ) and contains( text(), "preview=true" ) and contains( text(), "unload" ) and contains( text(), "window.name" ) and contains( text(), "wp-preview-%d" ) ]', 
+ '//script[ not( @src ) and contains( text(), "document.location.search" ) and contains( text(), "preview=true" ) and ( contains( text(), "pagehide" ) or contains( text(), "unload" ) ) and contains( text(), "window.name" ) and contains( text(), "wp-preview-%d" ) ]', 

[pavanpatil1]

QA Passed ✅

Verified the fix and it is working as expected. The validation error is no longer visible during post preview.

Actual result	Expected result