add support for absolute root ref as ~~/ and support for using root r…

…efs (~/, ~~/) with plain API methods

fixes #1958, fixes #2432

src/Ractive/construct.js

@@ -150,7 +150,7 @@ function initialiseProperties ( ractive ) {
 	ractive._children.byName = {};
 	ractive.children = ractive._children;
 
-	if(!ractive.component){
+	if ( !ractive.component ) {
 		ractive.root = ractive;
 		ractive.parent = ractive.container = null; // TODO container still applicable?
 	}

src/model/RootModel.js

@@ -114,6 +114,7 @@ export default class RootModel extends Model {
 
 		key = unescapeKey( key );
 		if ( key === '@this' || key === '@global' || key === '@shared' ) return true;
+		if ( ~key.indexOf( '~/' ) || ~key.indexOf( '~~/' ) ) return true;
 		if ( hasProp.call( value, key ) ) return true;
 
 		// mappings/links and computations
@@ -137,6 +138,11 @@ export default class RootModel extends Model {
 			return;
 		}
 
+		if ( key[0] === '~' ) {
+			if ( key[1] === '~' ) return this.ractive.root.viewmodel.joinKey( key.slice( 3 ) );
+			key = key.slice( 2 );
+		}
+
 		return this.computations.hasOwnProperty( key ) ? this.computations[ key ] :
 		       super.joinKey( key, opts );
 	}

src/parse/converters/expressions/primary/readReference.js

@@ -8,7 +8,7 @@ const globals = /^(?:Array|console|Date|RegExp|decodeURIComponent|decodeURI|enco
 // keywords are not valid references, with the exception of `this`
 const keywords = /^(?:break|case|catch|continue|debugger|default|delete|do|else|finally|for|function|if|in|instanceof|new|return|switch|throw|try|typeof|var|void|while|with)$/;
 
-const prefixPattern = /^(?:\@\.|\@|~\/|(?:\^\^\/(?:\^\^\/)*(?:\.\.\/)*)|(?:\.\.\/)+|\.\/(?:\.\.\/)*|\.)/;
+const prefixPattern = /^(?:\@\.|\@|~\/|~~\/|(?:\^\^\/(?:\^\^\/)*(?:\.\.\/)*)|(?:\.\.\/)+|\.\/(?:\.\.\/)*|\.)/;
 const specials = /^(key|index|keypath|rootpath|this|global)/;
 const specialCall = /^\s*\(/;
 

src/view/resolvers/resolveReference.js

@@ -10,7 +10,10 @@ export default function resolveReference ( fragment, ref ) {
 	if ( ref === '.' ) return fragment.findContext();
 
 	// ancestor references
-	if ( ref[0] === '~' ) return fragment.ractive.viewmodel.joinAll( splitKeypath( ref.slice( 2 ) ) );
+	if ( ref[0] === '~' ) {
+		if ( ref[1] === '~' ) return fragment.ractive.root.viewmodel.joinAll( splitKeypath( ref.slice( 3 ) ) );
+		return fragment.ractive.viewmodel.joinAll( splitKeypath( ref.slice( 2 ) ) );
+	}
 
 	// scoped references
 	if ( ref[0] === '.' || ref[0] === '^' ) {

test/browser-tests/references.js

@@ -249,4 +249,54 @@ export default function() {
 
 		t.htmlEqual( fixture.innerHTML, 'yepyep' );
 	});
+
+	test( 'component tree root data can be accessed with ~~/ (#2432)', t => {
+		const cmp = Ractive.extend({
+			template: '{{#with some.path}}{{~/foo}} {{~~/foo}}{{/with}}',
+			data: {
+				foo: 'cmp',
+				some: { path: {} }
+			}
+		});
+		new Ractive({
+			target: fixture,
+			template: '{{#with other.path}}<cmp />{{/with}}',
+			data: {
+				foo: 'root',
+				other: { path: {} }
+			},
+			components: { cmp }
+		});
+
+		t.htmlEqual( fixture.innerHTML, 'cmp root' );
+	});
+
+	test( 'root model will deal with ~/ and ~~/ references (#2432)', t => {
+		const cmp = Ractive.extend({
+			data: { foo: { bar: 'cmp' } }
+		});
+		const r = new Ractive({
+			target: fixture,
+			data: { foo: { bar: 'root' } },
+			template: '<cmp />',
+			components: { cmp }
+		});
+
+		const c = r.findComponent( 'cmp' );
+
+		t.equal( c.get( '~/foo.bar' ), 'cmp' );
+		t.equal( c.get( '~~/foo.bar' ), 'root' );
+	});
+
+	test( `trying to set a relative keypath from instance set warns and doesn't do unexpected things`, t => {
+		onWarn( w => {
+			t.ok( /relative keypath.*non-relative.*getNodeInfo.*event object/.test( w ) );
+		});
+
+		const r = new Ractive();
+
+		r.set( '.foo.bar', 'nope' );
+		t.ok( !r.get( 'foo.bar' ) );
+		t.ok( !( '' in r.get() ) );
+	});
 }