feat($compile): optionally get controllers from ancestors only

Implement option to strengthen require '^' operator, by adding another '^'.

When a second '^' is used, the controller will only search parent nodes for the
matching controller, and will throw or return null if not found, depending on
whether or not the requirement is optional.

Closes angular#4518

Author: Caitlin Potter

src/ng/compile.js

@@ -502,7 +502,9 @@ function $CompileProvider($provide, $$sanitizeUriProvider) {
   var hasDirectives = {},
       Suffix = 'Directive',
       COMMENT_DIRECTIVE_REGEXP = /^\s*directive\:\s*([\d\w\-_]+)\s+(.*)$/,
-      CLASS_DIRECTIVE_REGEXP = /(([\d\w\-_]+)(?:\:([^;]+))?;?)/;
+      CLASS_DIRECTIVE_REGEXP = /(([\d\w\-_]+)(?:\:([^;]+))?;?)/,
+      REQUIRE_PREFIX_REGEXP = /(\?)|(\^\^?)/g,
+      REQUIRE_PREFIX_PRE_REGEXP = /^((\?)|(\^\^?))+/;
 
   // Ref: http://developers.whatwg.org/webappapis.html#event-handler-idl-attributes
   // The assumption is that future DOM event attribute names will begin with
@@ -1343,21 +1345,27 @@ function $CompileProvider($provide, $$sanitizeUriProvider) {
 
 
       function getControllers(require, $element, elementControllers) {
-        var value, retrievalMethod = 'data', optional = false;
+        var value, retrievalMethod = 'data', optional = false, search = $element, prematch, match;
         if (isString(require)) {
-          while((value = require.charAt(0)) == '^' || value == '?') {
-            require = require.substr(1);
-            if (value == '^') {
-              retrievalMethod = 'inheritedData';
+          if ((prematch = require.match(REQUIRE_PREFIX_PRE_REGEXP)) &&
+              (match = prematch[0].match(REQUIRE_PREFIX_REGEXP))) {
+            for (var i=0, ii=match.length; i<ii; ++i) {
+              value = match[i];
+              switch (value) {
+                case '^': retrievalMethod = 'inheritedData'; break;
+                case '^^': retrievalMethod = 'inheritedData'; search = $element.parent(); break;
+                case '?': optional = true; break;
+              }
             }
-            optional = optional || value == '?';
+
+            require = require.substring(prematch[0].length);
           }
           value = null;
 
           if (elementControllers && retrievalMethod === 'data') {
             value = elementControllers[require];
           }
-          value = value || $element[retrievalMethod]('$' + require + 'Controller');
+          value = value || search[retrievalMethod]('$' + require + 'Controller');
 
           if (!value && !optional) {
             throw $compileMinErr('ctreq',

test/ng/compileSpec.js

@@ -2680,6 +2680,43 @@ describe('$compile', function() {
     });
 
 
+    it('should get required parent controller', function() {
+      module(function() {
+        directive('nested', function(log) {
+          return {
+            require: '^^?nested',
+            controller: function($scope) {},
+            link: function(scope, element, attrs, controller) {
+              log(!!controller);
+            }
+          };
+        });
+      });
+      inject(function(log, $compile, $rootScope) {
+        element = $compile('<div nested><div nested></div></div>')($rootScope);
+        expect(log).toEqual('true; false');
+      });
+    });
+
+
+    it('should throw if required parent is not found', function() {
+      module(function() {
+        directive('nested', function() {
+          return {
+            require: '^^nested',
+            controller: function($scope) {},
+            link: function(scope, element, attrs, controller) {}
+          };
+        });
+      });
+      inject(function($compile, $rootScope) {
+        expect(function() {
+          element = $compile('<div nested></div>')($rootScope);
+        }).toThrowMinErr('$compile', 'ctreq', "Controller 'nested', required by directive 'nested', can't be found!");
+      });
+    })
+
+
     it('should get required controller via linkingFn (template)', function() {
       module(function() {
         directive('dirA', function() {