ARIA required context role

Applicability

This rule applies to any [HTML or SVG element][] that is [included in the accessibility tree][] and has a [WAI-ARIA 1.2][aria 1.2] [explicit semantic role][] with a [required context role][], except if the element has an [implicit semantic role][] that is identical to its [explicit semantic role][].

Expectation

Each test target is the child in the [accessibility tree][] of an element that has a [semantic role][] that is one of the [required context roles][] of the target element.

Assumptions

The rule assumes that the [explicit role][] of the applicable elements is appropriate for their element. I.e. A heading incorrectly marked up with role="cell" does not fail [success criterion 1.3.1 Info and Relationships][sc131] for not being in the context of a row. Having an inappropriate role is itself an issue under 1.3.1 Info and Relationships, so in either scenario a failure of this rule means this success criterion is not satisfied.

Accessibility Support

User agents do not all have the same accessibility tree. This can lead to different results for this rule, depending on which accessibility tree is used as input.
aria-owns has limited support in some user agents.
There exist some combination of popular browsers and assistive technologies who do not announce correctly relationships based on a mix of [implicit][implicit role] and [explicit][explicit role] roles.

Background

The applicability of this rule is limited to the [WAI-ARIA 1.2 Recommendation][aria 1.2] roles. The [WAI-ARIA Graphics Module][] does not include any [required context roles][]. The [Digital Publishing WAI-ARIA Module (DPUB ARIA) 1.0][dpub 1.0] only has two roles with [required context roles][] (doc-biblioentry and doc-endnote); both of them have issues with their use of role inheritance, and both of them are deprecated in the [Digital Publishing WAI-ARIA Module (DPUB ARIA) 1.1][dpub 1.1] editor's draft.

An example of an element that has an [implicit semantic role][] that is identical to its [explicit semantic role][] is a <li role="listitem"> element. These elements are not applicable because they have extra requirements and should thus be checked separately.

Being a child in the [accessibility tree][] is different from being a child in the DOM tree. Some DOM nodes have no corresponding node in the [accessibility tree][] (for example, because they are marked with role="presentation"). A child in the [accessibility tree][] can thus correspond to a descendant in the DOM tree. Additionally, the use of aria-owns attribute can change the tree structure to something which is not a subtree of the DOM tree.

This rule is restricted to direct parent-child relation in the [accessibility tree][] which is more strict than the definition of "owned element" in WAI-ARIA. This rule mimics, on the roles level, the content model of HTML.

AI Prompt

Create a PHP class in the namespace "App\Services\AccessibilityAnalyzer\ActRules"
that extends "App\Services\AccessibilityAnalyzer\ActRuleRunner" and is called "AriaRequiredContextRoleFf89c9" that has a function with the signature "protected function findApplicableElements(Crawler $crawler): Crawler". The base class includes the function "protected function isElementIncludedInAccessibilityTree(\DOMNode $element): bool" for determining if an element is included in the accessibility tree.

Web accessibility rule:

# ARIA required context role

metadata:
    id: ff89c9
    name: 'ARIA required context role'
    rule_type: atomic
    description: "This rule checks that an element with an explicit semantic role exists inside its required context.\n"
    accessibility_requirements: { 'wcag20:1.3.1': { forConformance: true, failed: 'not satisfied', passed: 'further testing needed', inapplicable: 'further testing needed' } }
    input_aspects: ['Accessibility tree', 'CSS styling', 'DOM Tree']
    acknowledgments: { authors: ['Brian Bors', 'Jean-Yves Moyen', 'Wilco Fiers'], previous_authors: ['Anne Thyme Nørregaard'], funding: [WAI-Tools] }

## Applicability

This rule applies to any [HTML or SVG element][] that is [included in the accessibility tree][] and has a [WAI-ARIA 1.2][aria 1.2] [explicit semantic role][] with a [required context role][], except if the element has an [implicit semantic role][] that is identical to its [explicit semantic role][].

## Expectation

Each test target is the child in the [accessibility tree][] of an element that has a [semantic role][] that is one of the [required context roles][] of the target element.

## Assumptions

The rule assumes that the [explicit role][] of the applicable elements is appropriate for their element. I.e. A heading incorrectly marked up with `role="cell"` does not fail [success criterion 1.3.1 Info and Relationships][sc131] for not being in the context of a `row`. Having an inappropriate role is itself an issue under 1.3.1 Info and Relationships, so in either scenario a failure of this rule means this success criterion is not satisfied.

## Accessibility Support

- User agents do not all have the same accessibility tree. This can lead to different results for this rule, depending on which accessibility tree is used as input.
- `aria-owns` has limited support in some user agents.
- There exist some combination of popular browsers and assistive technologies who do not announce correctly relationships based on a mix of [implicit][implicit role] and [explicit][explicit role] roles.

## Background

The applicability of this rule is limited to the [WAI-ARIA 1.2 Recommendation][aria 1.2] roles. The [WAI-ARIA Graphics Module][] does not include any [required context roles][]. The [Digital Publishing WAI-ARIA Module (DPUB ARIA) 1.0][dpub 1.0] only has two roles with [required context roles][] (`doc-biblioentry` and `doc-endnote`); both of them have issues with their use of role inheritance, and both of them are deprecated in the [Digital Publishing WAI-ARIA Module (DPUB ARIA) 1.1][dpub 1.1] editor's draft.

An example of an element that has an [implicit semantic role][] that is identical to its [explicit semantic role][] is a `<li role="listitem">` element. These elements are not applicable because they have extra requirements and should thus be checked separately.

Being a child in the [accessibility tree][] is different from being a child in the DOM tree. Some DOM nodes have no corresponding node in the [accessibility tree][] (for example, because they are marked with `role="presentation"`). A child in the [accessibility tree][] can thus correspond to a descendant in the DOM tree. Additionally, the use of `aria-owns` attribute can change the tree structure to something which is not a subtree of the DOM tree.

This rule is restricted to direct parent-child relation in the [accessibility tree][] which is more strict than the definition of ["owned element" in WAI-ARIA](https://www.w3.org/TR/wai-aria-1.2/#dfn-owned-element). This rule mimics, on the roles level, the [content model](https://html.spec.whatwg.org/#concept-element-content-model) of HTML.