Deprecated the Promise config setting

4.0 will only support environments that have native promises, so there will
no longer be a need for a user-supplied promise library

lib/jasmine-core/jasmine.js

@@ -1175,6 +1175,8 @@ getJasmineRequireObj().Env = function(j$) {
        * @since 3.5.0
        * @type function
        * @default undefined
+       * @deprecated In a future version, Jasmine will ignore the Promise config
+       * property and always create native promises instead.
        */
       Promise: undefined,
       /**
@@ -1331,6 +1333,11 @@ getJasmineRequireObj().Env = function(j$) {
           typeof configuration.Promise.reject === 'function'
         ) {
           customPromise = configuration.Promise;
+          self.deprecated(
+            'The `Promise` config property is deprecated. Future versions ' +
+              'of Jasmine will create native promises even if the `Promise` ' +
+              'config property is set. Please remove it.'
+          );
         } else {
           throw new Error(
             'Custom promise library missing `resolve`/`reject` functions'

spec/core/EnvSpec.js

@@ -399,11 +399,17 @@ describe('Env', function() {
     });
 
     it('can be configured with a custom library', function() {
+      spyOn(env, 'deprecated');
       var myLibrary = {
         resolve: jasmine.createSpy(),
         reject: jasmine.createSpy()
       };
       env.configure({ Promise: myLibrary });
+      expect(env.deprecated).toHaveBeenCalledWith(
+        'The `Promise` config property is deprecated. Future versions of ' +
+          'Jasmine will create native promises even if the `Promise` config ' +
+          'property is set. Please remove it.'
+      );
     });
 
     it('cannot be configured with an invalid promise library', function() {

spec/core/SpySpec.js

@@ -271,6 +271,7 @@ describe('Spies', function() {
         reject: jasmine.createSpy()
       };
       customPromise.resolve.and.returnValue('resolved');
+      spyOn(env, 'deprecated');
       env.configure({ Promise: customPromise });
 
       var spy = env.createSpy('foo').and.resolveTo(42);

src/core/Env.js

@@ -137,6 +137,8 @@ getJasmineRequireObj().Env = function(j$) {
        * @since 3.5.0
        * @type function
        * @default undefined
+       * @deprecated In a future version, Jasmine will ignore the Promise config
+       * property and always create native promises instead.
        */
       Promise: undefined,
       /**
@@ -293,6 +295,11 @@ getJasmineRequireObj().Env = function(j$) {
           typeof configuration.Promise.reject === 'function'
         ) {
           customPromise = configuration.Promise;
+          self.deprecated(
+            'The `Promise` config property is deprecated. Future versions ' +
+              'of Jasmine will create native promises even if the `Promise` ' +
+              'config property is set. Please remove it.'
+          );
         } else {
           throw new Error(
             'Custom promise library missing `resolve`/`reject` functions'