`$singleTextNode->is(':text')` throws

[rulatir]

Guidelines

• I understand that if I fail to provide all required details, this issue may be closed without review.

Description of the bug

Invoking ->is(':text') on a QueryPath object that contains a single text node throws.

This is the sixth PHP DOM library I'm trying this week, so with each new one I start by writing a couple of suitability tests. This is the first suitability test I wrote for querypath, and should serve as repro.

Expected: passing test

Actual:

Error: Call to undefined method DOMText::getElementsByTagName()
/home/rulatir/projects/cdatify/vendor/gravitypdf/querypath/src/CSS/DOMTraverser.php:595
/home/rulatir/projects/cdatify/vendor/gravitypdf/querypath/src/CSS/DOMTraverser.php:444
/home/rulatir/projects/cdatify/vendor/gravitypdf/querypath/src/CSS/DOMTraverser.php:144
/home/rulatir/projects/cdatify/vendor/gravitypdf/querypath/src/DOMQuery.php:161
/home/rulatir/projects/cdatify/vendor/gravitypdf/querypath/src/DOMQuery.php:1481
/home/rulatir/projects/cdatify/vendor/gravitypdf/querypath/src/Helpers/QueryChecks.php:66
/home/rulatir/projects/cdatify/tests/QueryPathSuitability.php:26

QueryPath version

3.2.3

PHP Version and environment (server type, cli provider etc., enclosing libraries and their respective versions)

8.3.4 (cli) on up-to-date Arch Linux

Minimal reproducible PHP+HTML snippet to replicate bug

<?php

use PHPUnit\Framework\TestCase;

class QueryPathSuitability extends TestCase
{
    public function testCheckingNodeType(): void
    {
        $q = html5qp('<processing-container>whatever</processing-container>');

        $container = $q->find('processing-container');
        self::assertEquals(1, $container->length);

        $contents = $container->contents();
        self::assertEquals(1, $contents->length);

        $firstItem = $contents->eq(0);
        self::assertEquals(1, $firstItem->length);

        // RELEVANT BIT STARTS HERE

        // nonidiomatic way works
        self::assertStringContainsString("Text", get_class($firstItem->toArray()[0]));

        // idiomatic way throws
        self::assertTrue($firstItem->is(':text'));
    }
}

[jakejackson1]

Hi @rulatir,

Thanks for taking the time to report this. We certainly will want to fix the PHP error that's occurring when passing this pseudo-class selector to is().

You should be aware that even when we do, your test self::assertTrue($firstItem->is(':text')); will fail. This library was originally created as the PHP equivalent of jQuery. In jQuery the custom pseudo-class selector :text only matches the <input> and <input type="text"/> tags. It won't tell you if $firstItem is a text node.

Source: https://api.jquery.com/text-selector/

[rulatir]

What is then the idiomatic way to determine whether the collection is holding a text node? $q->get(0) instanceof DOMText?

Note to self: don't ask AI how to code things.

[jakejackson1]

@rulatir the QueryPath way would be $this->assertNotEmpty($firstItem->text());, which will return the contents of textContent for all matches in the current collection.

But if you really need low-level access to the DOM classes in a collection, this can be done via ->toArray() or ->get(). You can then check the class type or $item->nodeType (https://www.php.net/manual/en/dom.constants.php).

I've incorporated your bug report into a draft pull request so the PHP error can be fixed in the future: #50. If you have further questions about using QueryPath please open a Discussion: https://github.com/GravityPDF/querypath/discussions