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HTML API: Delete all copies of an attribute when removing and duplica…
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…tes exist. (WordPress#4317)

When encountering an HTML tag with duplicate copies of an attribute the tag
processor ignores the duplicate values, according to the specification. However,
when removing an attribute it must remove all copies of that attribute lest
one of the duplicates becomes the primary and it appears as if no attributes
were removed.

In this patch we're adding tests that will be used to ensure that all attribute
copies are removed from a tag when one is requested to be removed.

Co-authored-by: Bernie Reiter <96308+ockham@users.noreply.github.com>
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@dmsnell @ockham
dmsnell and ockham committed Sep 25, 2023
1 parent a68650e commit 3399f68
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Showing 2 changed files with 105 additions and 15 deletions.
51 changes: 46 additions & 5 deletions src/wp-includes/html-api/class-wp-html-tag-processor.php
View file
Original file line number Diff line number Diff line change
Expand Up @@ -406,6 +406,16 @@ class WP_HTML_Tag_Processor {
*/
private $attributes = array();

/**
* Tracks spans of duplicate attributes on a given tag, used for removing
* all copies of an attribute when calling `remove_attribute()`.
*
* @since 6.3.2
*
* @var (WP_HTML_Span[])[]|null
*/
private $duplicate_attributes = null;

/**
* Which class names to add or remove from a tag.
*
Expand Down Expand Up @@ -1286,6 +1296,25 @@ private function parse_next_attribute() {
$attribute_end,
! $has_value
);

return true;
}

/*
* Track the duplicate attributes so if we remove it, all disappear together.
*
* While `$this->duplicated_attributes` could always be stored as an `array()`,
* which would simplify the logic here, storing a `null` and only allocating
* an array when encountering duplicates avoids needless allocations in the
* normative case of parsing tags with no duplicate attributes.
*/
$duplicate_span = new WP_HTML_Span( $attribute_start, $attribute_end );
if ( null === $this->duplicate_attributes ) {
$this->duplicate_attributes = array( $comparable_name => array( $duplicate_span ) );
} elseif ( ! array_key_exists( $comparable_name, $this->duplicate_attributes ) ) {
$this->duplicate_attributes[ $comparable_name ] = array( $duplicate_span );
} else {
$this->duplicate_attributes[ $comparable_name ][] = $duplicate_span;
}

return true;
Expand All @@ -1307,11 +1336,12 @@ private function skip_whitespace() {
*/
private function after_tag() {
$this->get_updated_html();
$this->tag_name_starts_at = null;
$this->tag_name_length = null;
$this->tag_ends_at = null;
$this->is_closing_tag = null;
$this->attributes = array();
$this->tag_name_starts_at = null;
$this->tag_name_length = null;
$this->tag_ends_at = null;
$this->is_closing_tag = null;
$this->attributes = array();
$this->duplicate_attributes = null;
}

/**
Expand Down Expand Up @@ -2080,6 +2110,17 @@ public function remove_attribute( $name ) {
''
);

// Removes any duplicated attributes if they were also present.
if ( null !== $this->duplicate_attributes && array_key_exists( $name, $this->duplicate_attributes ) ) {
foreach ( $this->duplicate_attributes[ $name ] as $attribute_token ) {
$this->lexical_updates[] = new WP_HTML_Text_Replacement(
$attribute_token->start,
$attribute_token->end,
''
);
}
}

return true;
}

Expand Down
69 changes: 59 additions & 10 deletions tests/phpunit/tests/html-api/wpHtmlTagProcessor.php
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1049,15 +1049,9 @@ public function test_next_tag_and_set_attribute_in_a_loop_update_all_tags_in_the
* Removing an attribute that's listed many times, e.g. `<div id="a" id="b" />` should remove
* all its instances and output just `<div />`.
*
* Today, however, WP_HTML_Tag_Processor only removes the first such attribute. It seems like a corner case
* and introducing additional complexity to correctly handle this scenario doesn't seem to be worth it.
* Let's revisit if and when this becomes a problem.
* @since 6.3.2 Removes all duplicated attributes as expected.
*
* This test is in place to confirm this behavior, which while incorrect, is well-defined.
* A later fix introduced to the Tag Processor should update this test to reflect the
* wanted and correct behavior.
*
* @ticket 56299
* @ticket 58119
*
* @covers WP_HTML_Tag_Processor::remove_attribute
*/
Expand All @@ -1066,8 +1060,8 @@ public function test_remove_first_when_duplicated_attribute() {
$p->next_tag();
$p->remove_attribute( 'id' );

$this->assertSame(
'<div id="ignored-id"><span id="second">Text</span></div>',
$this->assertStringNotContainsString(
'update-me',
$p->get_updated_html(),
'First attribute (when duplicates exist) was not removed'
);
Expand All @@ -1090,6 +1084,61 @@ public function test_remove_attribute_with_an_existing_attribute_name_removes_it
);
}

/**
* @ticket 58119
*
* @since 6.3.2 Removes all duplicated attributes as expected.
*
* @covers WP_HTML_Tag_Processor::remove_attribute
*
* @dataProvider data_html_with_duplicated_attributes
*/
public function test_remove_attribute_with_duplicated_attributes_removes_all_of_them( $html_with_duplicate_attributes, $attribute_to_remove ) {
$p = new WP_HTML_Tag_Processor( $html_with_duplicate_attributes );
$p->next_tag();

$p->remove_attribute( $attribute_to_remove );
$this->assertSame( null, $p->get_attribute( $attribute_to_remove ), 'Failed to remove all copies of an attribute when duplicated in modified source.' );

// Recreate a tag processor with the updated HTML after removing the attribute.
$p = new WP_HTML_Tag_Processor( $p->get_updated_html() );
$p->next_tag();
$this->assertNull( $p->get_attribute( $attribute_to_remove ), 'Failed to remove all copies of duplicated attributes when getting updated HTML.' );
}

/**
* @ticket 58119
*
* @since 6.3.2 Removes all duplicated attributes as expected.
*
* @covers WP_HTML_Tag_Processor::remove_attribute
*/
public function test_previous_duplicated_attributes_are_not_removed_on_successive_tag_removal() {
$p = new WP_HTML_Tag_Processor( '<span id=one id=two id=three><span id=four>' );
$p->next_tag();
$p->next_tag();
$p->remove_attribute( 'id' );

$this->assertSame( '<span id=one id=two id=three><span >', $p->get_updated_html() );
}

/**
* Data provider.
*
* @ticket 58119
*
* @return array[].
*/
public function data_html_with_duplicated_attributes() {
return array(
'Double attributes' => array( '<div id=one id=two>', 'id' ),
'Triple attributes' => array( '<div id=one id=two id=three>', 'id' ),
'Duplicates around another' => array( '<img src="test.png" alt="kites flying in the wind" src="kites.jpg">', 'src' ),
'Case-variants of attribute' => array( '<button disabled inert DISABLED dISaBled INERT DisABleD>', 'disabled' ),
'Case-variants of attribute name' => array( '<button disabled inert DISABLED dISaBled INERT DisABleD>', 'DISABLED' ),
);
}

/**
* @ticket 56299
*
Expand Down

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