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

@@ -212,8 +212,11 @@
  * * (no prefix) - Locate the required controller on the current element. Throw an error if not found.
  * * `?` - Attempt to locate the required controller or pass `null` to the `link` fn if not found.
  * * `^` - Locate the required controller by searching the element and its parents. Throw an error if not found.
+ * * `^^` - Locate the required controller by searching the element's parents. Throw an error if not found.
  * * `?^` - Attempt to locate the required controller by searching the element and its parents or pass
  *   `null` to the `link` fn if not found.
+ * * `?^^` - Attempt to locate the required controller by searching the element's parents, or pass
+ *   `null` to the `link` fn if not found.
  *
  *
  * #### `controllerAs`
@@ -567,7 +570,8 @@ function $CompileProvider($provide, $$sanitizeUriProvider) {
       Suffix = 'Directive',
       COMMENT_DIRECTIVE_REGEXP = /^\s*directive\:\s*([\d\w_\-]+)\s+(.*)$/,
       CLASS_DIRECTIVE_REGEXP = /(([\d\w_\-]+)(?:\:([^;]+))?;?)/,
-      ALL_OR_NOTHING_ATTRS = makeMap('ngSrc,ngSrcset,src,srcset');
+      ALL_OR_NOTHING_ATTRS = makeMap('ngSrc,ngSrcset,src,srcset'),
+      REQUIRE_PREFIX_REGEXP = /^(?:(\^\^?)?(\?)?(\^\^?)?)?/;
 
   // Ref: http://developers.whatwg.org/webappapis.html#event-handler-idl-attributes
   // The assumption is that future DOM event attribute names will begin with
@@ -1589,22 +1593,34 @@ function $CompileProvider($provide, $$sanitizeUriProvider) {
 
       function getControllers(directiveName, require, $element, elementControllers) {
         var value, retrievalMethod = 'data', optional = false;
+        var $searchElement = $element;
+        var match;
         if (isString(require)) {
-          while((value = require.charAt(0)) == '^' || value == '?') {
-            require = require.substr(1);
-            if (value == '^') {
-              retrievalMethod = 'inheritedData';
-            }
-            optional = optional || value == '?';
+          match = require.match(REQUIRE_PREFIX_REGEXP);
+          require = require.substring(match[0].length);
+
+          if (match[3]) {
+            if (match[1]) match[3] = null;
+            else match[1] = match[3];
           }
+          if (match[1] === '^') {
+            retrievalMethod = 'inheritedData';
+          } else if (match[1] === '^^') {
+            retrievalMethod = 'inheritedData';
+            $searchElement = $element.parent();
+          }
+          if (match[2] === '?') {
+            optional = true;
+          }
+
           value = null;
 
           if (elementControllers && retrievalMethod === 'data') {
             if (value = elementControllers[require]) {
               value = value.instance;
             }
           }
-          value = value || $element[retrievalMethod]('$' + require + 'Controller');
+          value = value || $searchElement[retrievalMethod]('$' + require + 'Controller');
 
           if (!value && !optional) {
             throw $compileMinErr('ctreq',

test/ng/compileSpec.js

@@ -3672,6 +3672,43 @@ 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() {