fix(target-size): ignore descendant elements in shadow dom

.eslintrc.js

@@ -59,13 +59,37 @@ module.exports = {
         selector: 'MemberExpression[property.name=tagName]',
         message: "Don't use node.tagName, use node.nodeName instead."
       },
+      // node.attributes can be clobbered so is unsafe to use
+      // @see https://github.com/dequelabs/axe-core/pull/1432
       {
-        // node.attributes can be clobbered so is unsafe to use
-        // @see https://github.com/dequelabs/axe-core/pull/1432
+        // node.attributes
         selector:
           'MemberExpression[object.name=node][property.name=attributes]',
         message:
           "Don't use node.attributes, use node.hasAttributes() or axe.utils.getNodeAttributes(node) instead."
+      },
+      {
+        // vNode.actualNode.attributes
+        selector:
+          'MemberExpression[object.property.name=actualNode][property.name=attributes]',
+        message:
+          "Don't use node.attributes, use node.hasAttributes() or axe.utils.getNodeAttributes(node) instead."
+      },
+      // node.contains doesn't work with shadow dom
+      // @see https://github.com/dequelabs/axe-core/issues/4194
+      {
+        // node.contains()
+        selector:
+          'CallExpression[callee.object.name=node][callee.property.name=contains]',
+        message:
+          "Don't use node.contains(node2), use axe.utils.contains(node, node2) instead."
+      },
+      {
+        // vNode.actualNode.contains()
+        selector:
+          'CallExpression[callee.object.property.name=actualNode][callee.property.name=contains]',
+        message:
+          "Don't use node.contains(node2), use axe.utils.contains(node, node2) instead."
       }
     ]
   },

lib/checks/mobile/target-size-evaluate.js

@@ -5,6 +5,7 @@ import {
   rectHasMinimumSize,
   hasVisualOverlap
 } from '../../commons/math';
+import { contains } from '../../core/utils';
 
 /**
  * Determine if an element has a minimum size, taking into account
@@ -185,9 +186,7 @@ function toDecimalSize(rect) {
 }
 
 function isDescendantNotInTabOrder(vAncestor, vNode) {
-  return (
-    vAncestor.actualNode.contains(vNode.actualNode) && !isInTabOrder(vNode)
-  );
+  return contains(vAncestor, vNode) && !isInTabOrder(vNode);
 }
 
 function mapActualNodes(vNodes) {

lib/commons/dom/get-target-rects.js

@@ -2,6 +2,7 @@ import findNearbyElms from './find-nearby-elms';
 import isInTabOrder from './is-in-tab-order';
 import { splitRects, hasVisualOverlap } from '../math';
 import memoize from '../../core/utils/memoize';
+import { contains } from '../../core/utils';
 
 export default memoize(getTargetRects);
 
@@ -32,7 +33,5 @@ function getTargetRects(vNode) {
 }
 
 function isDescendantNotInTabOrder(vAncestor, vNode) {
-  return (
-    vAncestor.actualNode.contains(vNode.actualNode) && !isInTabOrder(vNode)
-  );
+  return contains(vAncestor, vNode) && !isInTabOrder(vNode);
 }

lib/core/utils/contains.js

@@ -12,8 +12,10 @@ export default function contains(vNode, otherVNode) {
     !vNode.shadowId &&
     !otherVNode.shadowId &&
     vNode.actualNode &&
+    // eslint-disable-next-line no-restricted-syntax
     typeof vNode.actualNode.contains === 'function'
   ) {
+    // eslint-disable-next-line no-restricted-syntax
     return vNode.actualNode.contains(otherVNode.actualNode);
   }
 

test/commons/dom/get-target-rects.js

@@ -1,6 +1,8 @@
 describe('get-target-rects', () => {
   const getTargetRects = axe.commons.dom.getTargetRects;
+  const shadowSupport = axe.testUtils.shadowSupport.v1;
   const { queryFixture } = axe.testUtils;
+  const fixture = document.getElementById('fixture');
 
   it('returns the bounding rect when unobscured', () => {
     const vNode = queryFixture('<button id="target">x</button>');
@@ -74,10 +76,28 @@ describe('get-target-rects', () => {
       </button>
     `);
     const rects = getTargetRects(vNode);
-    console.log(JSON.stringify(rects));
     assert.deepEqual(rects, [
       new DOMRect(10, 5, 30, 7),
       new DOMRect(10, 5, 7, 40)
     ]);
   });
+
+  (shadowSupport ? it : xit)(
+    'ignores non-tabbable descendants of the target that are in shadow dom',
+    () => {
+      fixture.innerHTML =
+        '<button id="target" style="width: 30px; height: 40px; position: absolute; left: 10px; top: 5px"><span id="shadow"></span></button>';
+      const target = fixture.querySelector('#target');
+      const shadow = fixture
+        .querySelector('#shadow')
+        .attachShadow({ mode: 'open' });
+      shadow.innerHTML =
+        '<div style="position: absolute; left: 5px; top: 5px; width: 50px; height: 50px;"></div>';
+
+      axe.setup(fixture);
+      const vNode = axe.utils.getNodeFromTree(target);
+      const rects = getTargetRects(vNode);
+      assert.deepEqual(rects, [vNode.actualNode.getBoundingClientRect()]);
+    }
+  );
 });

test/integration/full/target-size/shadow-dom.html

@@ -0,0 +1,66 @@
+<!doctype html>
+<html lang="en">
+  <head>
+    <title>Target-size too many rects Test</title>
+    <link
+      rel="stylesheet"
+      type="text/css"
+      href="/node_modules/mocha/mocha.css"
+    />
+    <script src="/node_modules/mocha/mocha.js"></script>
+    <script src="/node_modules/chai/chai.js"></script>
+    <script src="/axe.js"></script>
+    <script>
+      mocha.setup({
+        timeout: 10000,
+        ui: 'bdd'
+      });
+      var assert = chai.assert;
+    </script>
+  </head>
+  <body>
+    <main id="mocha"></main>
+    <script>
+      const shadowTemplate = document.createElement('template');
+      shadowTemplate.innerHTML =
+        '<div id="shadow-container"><slot></slot></div>';
+      class ShadowOpenWebComponent extends HTMLElement {
+        connectedCallback() {
+          const shadowRoot = this.attachShadow({ mode: 'open' });
+          shadowRoot.appendChild(shadowTemplate.content.cloneNode(true));
+        }
+      }
+
+      customElements.define('shadow-open', ShadowOpenWebComponent);
+    </script>
+    <style>
+      #container {
+        font-size: 16px;
+      }
+      #title {
+        background-color: #cff;
+      }
+      #content {
+        background-color: #cfc;
+        margin-top: 10px;
+      }
+    </style>
+    <div id="container">
+      <div id="title">
+        <a id="title-link" href="#target">
+          <shadow-open>
+            <div>Title</div>
+          </shadow-open>
+        </a>
+      </div>
+      <div id="content">
+        <a id="content-link" href="#target">
+          <div>Content</div>
+        </a>
+      </div>
+    </div>
+    <script src="/test/testutils.js"></script>
+    <script src="shadow-dom.js"></script>
+    <script src="/test/integration/adapter.js"></script>
+  </body>
+</html>

test/integration/full/target-size/shadow-dom.js

@@ -0,0 +1,45 @@
+describe('target-size shadow dom test', () => {
+  'use strict';
+  let results;
+
+  before(done => {
+    axe.testUtils.awaitNestedLoad(() => {
+      const options = {
+        runOnly: ['target-size'],
+        elementRef: true
+      };
+      const context = {
+        // ignore the mocha links
+        exclude: '#mocha'
+      };
+      axe.run(context, options, (err, r) => {
+        if (err) {
+          done(err);
+        }
+        results = r;
+        console.log(results);
+        done();
+      });
+    });
+  });
+
+  describe('violations', function () {
+    it('should find 0', function () {
+      assert.lengthOf(results.violations, 0);
+    });
+  });
+
+  describe('passes', function () {
+    it('should find 2', function () {
+      assert.lengthOf(results.passes[0].nodes, 2);
+    });
+  });
+
+  it('should find 0 inapplicable', function () {
+    assert.lengthOf(results.inapplicable, 0);
+  });
+
+  it('should find 0 incomplete', function () {
+    assert.lengthOf(results.incomplete, 0);
+  });
+});