Core: Recognize Shadow DOM in attachment checks

Allow `isAttached` to check Shadow DOM for attachment.

Fixes gh-3504
Closes gh-3996
Ref gh-3977

8 files changed, 138 insertions, 15 deletions

diff --git a/src/core/isAttached.js b/src/core/isAttached.js
new file mode 100644
index 000000000..efa2465a9
--- /dev/null
+++ b/src/core/isAttached.js
@@ -0,0 +1,22 @@
+define( [
+	"../core",
+	"../var/documentElement",
+	"../selector" // jQuery.contains
+], function( jQuery, documentElement ) {
+	"use strict";
+
+	var isAttached = function( elem ) {
+			return jQuery.contains( elem.ownerDocument, elem );
+		},
+		composed = { composed: true };
+
+	// Check attachment across shadow DOM boundaries when possible (gh-3504)
+	if ( documentElement.attachShadow ) {
+		isAttached = function( elem ) {
+			return jQuery.contains( elem.ownerDocument, elem ) ||
+				elem.getRootNode( composed ) === elem.ownerDocument;
+		};
+	}
+
+	return isAttached;
+} );
diff --git a/src/css/curCSS.js b/src/css/curCSS.js
index 7fed20f17..98a594a77 100644
--- a/src/css/curCSS.js
+++ b/src/css/curCSS.js
@@ -1,6 +1,6 @@
 define( [
 	"../core",
-	"../var/isAttached",
+	"../core/isAttached",
 	"./var/rboxStyle",
 	"./var/rnumnonpx",
 	"./var/getStyles",
diff --git a/src/css/var/isHiddenWithinTree.js b/src/css/var/isHiddenWithinTree.js
index fd963a031..0ab610e29 100644
--- a/src/css/var/isHiddenWithinTree.js
+++ b/src/css/var/isHiddenWithinTree.js
@@ -1,6 +1,6 @@
 define( [
 	"../../core",
-	"../../var/isAttached"
+	"../../core/isAttached"
 
 	// css is assumed
 ], function( jQuery, isAttached ) {
diff --git a/src/manipulation.js b/src/manipulation.js
index 3c6d59262..a0e93f7ef 100644
--- a/src/manipulation.js
+++ b/src/manipulation.js
@@ -1,6 +1,6 @@
 define( [
 	"./core",
-	"./var/isAttached",
+	"./core/isAttached",
 	"./var/concat",
 	"./var/isFunction",
 	"./var/push",
diff --git a/src/manipulation/buildFragment.js b/src/manipulation/buildFragment.js
index 34bcc70c2..40c2ed1dc 100644
--- a/src/manipulation/buildFragment.js
+++ b/src/manipulation/buildFragment.js
@@ -1,7 +1,7 @@
 define( [
 	"../core",
 	"../core/toType",
-	"../var/isAttached",
+	"../core/isAttached",
 	"./var/rtagName",
 	"./var/rscriptType",
 	"./wrapMap",
diff --git a/src/var/isAttached.js b/src/var/isAttached.js
deleted file mode 100644
index 1dd798268..000000000
--- a/src/var/isAttached.js
+++ /dev/null
@@ -1,11 +0,0 @@
-define( [
-	"../core",
-	"../selector" // Get jQuery.contains
-], function( jQuery ) {
-	"use strict";
-
-	return function isAttached( obj ) {
-		return jQuery.contains( obj.ownerDocument, obj );
-	};
-
-} );
diff --git a/test/unit/css.js b/test/unit/css.js
index 7e08105d2..a197b6f04 100644
--- a/test/unit/css.js
+++ b/test/unit/css.js
@@ -641,6 +641,63 @@ QUnit.test( "show/hide detached nodes", function( assert ) {
 	span.remove();
 } );
 
+QUnit[ document.body.attachShadow ? "test" : "skip" ]( "show/hide shadow child nodes", function( assert ) {
+	assert.expect( 28 );
+	jQuery( "<div id='shadowHost'></div>" ).appendTo( "#qunit-fixture" );
+	var shadowHost = document.querySelector( "#shadowHost" );
+	var shadowRoot = shadowHost.attachShadow( { mode: "open" } );
+	shadowRoot.innerHTML = "" +
+		"<style>.hidden{display: none;}</style>" +
+		"<div class='hidden' id='shadowdiv'>" +
+		"	<p class='hidden' id='shadowp'>" +
+		"		<a href='#' class='hidden' id='shadowa'></a>" +
+		"	</p>" +
+		"	<code class='hidden' id='shadowcode'></code>" +
+		"	<pre class='hidden' id='shadowpre'></pre>" +
+		"	<span class='hidden' id='shadowspan'></span>" +
+		"</div>" +
+		"<table class='hidden' id='shadowtable'>" +
+		"	<thead class='hidden' id='shadowthead'>" +
+		"		<tr class='hidden' id='shadowtr'>" +
+		"			<th class='hidden' id='shadowth'></th>" +
+		"		</tr>" +
+		"	</thead>" +
+		"	<tbody class='hidden' id='shadowtbody'>" +
+		"		<tr class='hidden'>" +
+		"			<td class='hidden' id='shadowtd'></td>" +
+		"		</tr>" +
+		"	</tbody>" +
+		"</table>" +
+		"<ul class='hidden' id='shadowul'>" +
+		"	<li class='hidden' id='shadowli'></li>" +
+		"</ul>";
+
+	var test = {
+		"div": "block",
+		"p": "block",
+		"a": "inline",
+		"code": "inline",
+		"pre": "block",
+		"span": "inline",
+		"table": "table",
+		"thead": "table-header-group",
+		"tbody": "table-row-group",
+		"tr": "table-row",
+		"th": "table-cell",
+		"td": "table-cell",
+		"ul": "block",
+		"li": "list-item"
+	};
+
+	jQuery.each( test, function( selector, expected ) {
+		var shadowChild = shadowRoot.querySelector( "#shadow" + selector );
+		var $shadowChild = jQuery( shadowChild );
+		assert.strictEqual( $shadowChild.css( "display" ), "none", "is hidden" );
+		$shadowChild.show();
+		assert.strictEqual( $shadowChild.css( "display" ), expected, "Show using correct display type for " + selector );
+	} );
+} );
+
 QUnit.test( "hide hidden elements (bug #7141)", function( assert ) {
 	assert.expect( 3 );
 
@@ -966,6 +1023,29 @@ QUnit[ jQuery.find.compile && jQuery.fn.toggle ? "test" : "skip" ]( "detached to
 		"cascade-hidden element in detached tree" );
 } );
 
+QUnit[ jQuery.find.compile && jQuery.fn.toggle && document.body.attachShadow ? "test" : "skip" ]( "shadow toggle()", function( assert ) {
+	assert.expect( 4 );
+	jQuery( "<div id='shadowHost'></div>" ).appendTo( "#qunit-fixture" );
+	var shadowHost = document.querySelector( "#shadowHost" );
+	var shadowRoot = shadowHost.attachShadow( { mode: "open" } );
+	shadowRoot.innerHTML = "" +
+		"<style>.hidden{display: none;}</style>" +
+		"<div id='shadowHiddenChild' class='hidden'></div>" +
+		"<div id='shadowChild'></div>";
+	var shadowChild = shadowRoot.querySelector( "#shadowChild" );
+	var shadowHiddenChild = shadowRoot.querySelector( "#shadowHiddenChild" );
+
+	var $shadowChild = jQuery( shadowChild );
+	assert.strictEqual( $shadowChild.css( "display" ), "block", "is visible" );
+	$shadowChild.toggle();
+	assert.strictEqual( $shadowChild.css( "display" ), "none", "is hidden" );
+
+	$shadowChild = jQuery( shadowHiddenChild );
+	assert.strictEqual( $shadowChild.css( "display" ), "none", "is hidden" );
+	$shadowChild.toggle();
+	assert.strictEqual( $shadowChild.css( "display" ), "block", "is visible" );
+} );
+
 QUnit.test( "jQuery.css(elem, 'height') doesn't clear radio buttons (bug #1095)", function( assert ) {
 	assert.expect( 4 );
 
diff --git a/test/unit/effects.js b/test/unit/effects.js
index e297273e4..9e8838132 100644
--- a/test/unit/effects.js
+++ b/test/unit/effects.js
@@ -220,6 +220,38 @@ supportjQuery.each( hideOptions, function( type, setup ) {
 
 		assert.expectJqData( this, $span, "olddisplay" );
 	} );
+
+	QUnit[ document.body.attachShadow ? "test" : "skip" ](
+		"Persist correct display value - " + type + " hidden, shadow child", function( assert ) {
+		assert.expect( 3 );
+
+		jQuery( "<div id='shadowHost'></div>" ).appendTo( "#qunit-fixture" );
+
+		var shadowHost = document.querySelector( "#shadowHost" );
+		var shadowRoot = shadowHost.attachShadow( { mode: "open" } );
+		shadowRoot.innerHTML = "<style>.hidden{display: none;}</style>" +
+			"<span id='shadowChild' class='hidden'></span>";
+		var shadowChild = shadowRoot.querySelector( "#shadowChild" );
+
+		var $shadowChild = jQuery( shadowChild );
+		var displayNone = "none";
+		var display = "inline";
+		var clock = this.clock;
+
+		$shadowChild.fadeIn( 100, function() {
+			assert.equal( $shadowChild.css( "display" ), display, "Expecting shadow display: " + display );
+			$shadowChild.fadeOut( 100, function() {
+				assert.equal( $shadowChild.css( "display" ), displayNone, "Expecting shadow display: " + displayNone );
+				$shadowChild.fadeIn( 100, function() {
+					assert.equal( $shadowChild.css( "display" ), display, "Expecting shadow display: " + display );
+				} );
+			} );
+		} );
+
+		clock.tick( 300 );
+
+		assert.expectJqData( this, $shadowChild, "olddisplay" );
+	} );
 } );
 
 QUnit.test( "animate(Hash, Object, Function)", function( assert ) {