fix($compile): attribute bindings should not break due to terminal directives

Recently we changed the priority of attribute interpolation directive to -100
to ensure that it executes early in the post linking phase. This causes issues
with when terminal directives are placed on elements with attribute bindings
because the terminal directive will usually have 0 or higher priority which
results in attr interpolation directive not being applied to the element.

To fix this issue I'm switching the priority back to 100 and making moving the
binding setup into the pre-linking function.

This means that:

- terminal directives with priority lower than 100 will not affect the attribute
  binding
- if a directive wants to add or alter bindings it can do so in the pre-linking
  phase, as long as the priority of this directive is more than 100
- all post-linking functions will execute after the attribute binding has been
  set up
- all pre-linking functions with directive priority lower than 100 will execute
  after the attribute bindings have been setup

BREAKING CHANGE: the attribute interpolation (binding) executes as a directive
with priority 100 and the binding is set up in the pre-linking phase. It used
to be that the priority was -100 in rc.2 (100 before rc.2) and that the binding
was setup in the post-linking phase.

Closes #4525
Closes #4528
Closes #4649

src/ng/compile.js

@@ -1717,33 +1717,37 @@ function $CompileProvider($provide) {
       }
 
       directives.push({
-        priority: -100,
-        compile: valueFn(function attrInterpolateLinkFn(scope, element, attr) {
-          var $$observers = (attr.$$observers || (attr.$$observers = {}));
+        priority: 100,
+        compile: function() {
+            return {
+              pre: function attrInterpolatePreLinkFn(scope, element, attr) {
+                var $$observers = (attr.$$observers || (attr.$$observers = {}));
 
-          if (EVENT_HANDLER_ATTR_REGEXP.test(name)) {
-            throw $compileMinErr('nodomevents',
-                "Interpolations for HTML DOM event attributes are disallowed.  Please use the " +
-                "ng- versions (such as ng-click instead of onclick) instead.");
+                if (EVENT_HANDLER_ATTR_REGEXP.test(name)) {
+                  throw $compileMinErr('nodomevents',
+                      "Interpolations for HTML DOM event attributes are disallowed.  Please use the " +
+                          "ng- versions (such as ng-click instead of onclick) instead.");
+                }
+
+                // we need to interpolate again, in case the attribute value has been updated
+                // (e.g. by another directive's compile function)
+                interpolateFn = $interpolate(attr[name], true, getTrustedContext(node, name));
+
+                // if attribute was updated so that there is no interpolation going on we don't want to
+                // register any observers
+                if (!interpolateFn) return;
+
+                // TODO(i): this should likely be attr.$set(name, iterpolateFn(scope) so that we reset the
+                // actual attr value
+                attr[name] = interpolateFn(scope);
+                ($$observers[name] || ($$observers[name] = [])).$$inter = true;
+                (attr.$$observers && attr.$$observers[name].$$scope || scope).
+                    $watch(interpolateFn, function interpolateFnWatchAction(value) {
+                      attr.$set(name, value);
+                    });
+              }
+            };
           }
-
-          // we need to interpolate again, in case the attribute value has been updated
-          // (e.g. by another directive's compile function)
-          interpolateFn = $interpolate(attr[name], true, getTrustedContext(node, name));
-
-          // if attribute was updated so that there is no interpolation going on we don't want to
-          // register any observers
-          if (!interpolateFn) return;
-
-          // TODO(i): this should likely be attr.$set(name, iterpolateFn(scope) so that we reset the
-          // actual attr value
-          attr[name] = interpolateFn(scope);
-          ($$observers[name] || ($$observers[name] = [])).$$inter = true;
-          (attr.$$observers && attr.$$observers[name].$$scope || scope).
-            $watch(interpolateFn, function interpolateFnWatchAction(value) {
-              attr.$set(name, value);
-            });
-        })
       });
     }
 

test/ng/compileSpec.js

@@ -1591,7 +1591,7 @@ describe('$compile', function() {
     );
 
 
-    it('should process attribute interpolation at the beginning of the post-linking phase', function() {
+    it('should process attribute interpolation in pre-linking phase at priority 100', function() {
       module(function() {
         directive('attrLog', function(log) {
           return {
@@ -1600,22 +1600,36 @@ describe('$compile', function() {
 
               return {
                 pre: function($scope, $element, $attrs) {
-                  log('preLink=' + $attrs.myName);
+                  log('preLinkP0=' + $attrs.myName);
                 },
-                post: function($scope, $element) {
+                post: function($scope, $element, $attrs) {
                   log('postLink=' + $attrs.myName);
                 }
               }
             }
           }
-        })
+        });
+      });
+      module(function() {
+        directive('attrLogHighPriority', function(log) {
+          return {
+            priority: 101,
+            compile: function() {
+              return {
+                pre: function($scope, $element, $attrs) {
+                  log('preLinkP101=' + $attrs.myName);
+                }
+              };
+            }
+          }
+        });
       });
       inject(function($rootScope, $compile, log) {
-        element = $compile('<div attr-log my-name="{{name}}"></div>')($rootScope);
+        element = $compile('<div attr-log-high-priority attr-log my-name="{{name}}"></div>')($rootScope);
         $rootScope.name = 'angular';
         $rootScope.$apply();
         log('digest=' + element.attr('my-name'));
-        expect(log).toEqual('compile={{name}}; preLink={{name}}; postLink=; digest=angular');
+        expect(log).toEqual('compile={{name}}; preLinkP101={{name}}; preLinkP0=; postLink=; digest=angular');
       });
     });
 
@@ -1758,6 +1772,32 @@ describe('$compile', function() {
         expect(element.text()).toBe('AHOJ|ahoj|AHOJ');
       });
     });
+
+
+    it('should make attributes observable for terminal directives', function() {
+      module(function() {
+        directive('myAttr', function(log) {
+          return {
+            terminal: true,
+            link: function(scope, element, attrs) {
+              attrs.$observe('myAttr', function(val) {
+                log(val);
+              });
+            }
+          }
+        });
+      });
+
+      inject(function($compile, $rootScope, log) {
+        element = $compile('<div my-attr="{{myVal}}"></div>')($rootScope);
+        expect(log).toEqual([]);
+
+        $rootScope.myVal = 'carrot';
+        $rootScope.$digest();
+
+        expect(log).toEqual(['carrot']);
+      });
+    })
   });