Prevent monkey patching

This doesn't affect globals (describe, it, expect, etc). Those belong to
the user and Jasmine doesn't depend on them.

lib/jasmine-core/jasmine.js

@@ -141,6 +141,28 @@ const getJasmineRequireObj = (function() {
 
     private$.loadedAsBrowserEsm = loadedAsBrowserEsm;
 
+    // Prevent monkey patching of existing properties but allow adding new ones.
+    // jasmine-html.js needs to be able to add to the jasmine namespace.
+    // jasmine-ajax also installs itself this way.
+    const writeable = [
+      'DEFAULT_TIMEOUT_INTERVAL',
+      'MAX_PRETTY_PRINT_ARRAY_LENGTH',
+      'MAX_PRETTY_PRINT_CHARS',
+      'MAX_PRETTY_PRINT_DEPTH'
+    ];
+    const descriptors = Object.getOwnPropertyDescriptors(j$);
+
+    for (const [k, d] of Object.entries(descriptors)) {
+      if (!writeable.includes(k)) {
+        Object.defineProperty(j$, k, {
+          value: d.value,
+          enumerable: d.enumerable,
+          configurable: false,
+          writable: false
+        });
+      }
+    }
+
     return { jasmine: j$, private: private$ };
   };
 
@@ -241,6 +263,7 @@ getJasmineRequireObj().base = function(j$, private$, jasmineGlobal) {
    */
   let DEFAULT_TIMEOUT_INTERVAL = 5000;
   Object.defineProperty(j$, 'DEFAULT_TIMEOUT_INTERVAL', {
+    enumerable: true,
     get: function() {
       return DEFAULT_TIMEOUT_INTERVAL;
     },
@@ -2077,6 +2100,8 @@ getJasmineRequireObj().Env = function(j$, private$) {
     this.cleanup_ = function() {
       uninstallGlobalErrors();
     };
+
+    Object.freeze(this);
   }
 
   function indirectCallerFilename(depth) {
@@ -2087,6 +2112,8 @@ getJasmineRequireObj().Env = function(j$, private$) {
     return frames[depth] && frames[depth].file;
   }
 
+  Object.freeze(Env);
+  Object.freeze(Env.prototype);
   return Env;
 };
 
@@ -3009,6 +3036,8 @@ callbacks to execute _before_ running the next one.
     setInterval[IsMockClockTimingFn] = true;
     clearInterval[IsMockClockTimingFn] = true;
 
+    Object.freeze(this);
+
     return this;
 
     // Advances the Clock's time until the mode changes.
@@ -3162,6 +3191,8 @@ callbacks to execute _before_ running the next one.
   };
 
   Clock.IsMockClockTimingFn = IsMockClockTimingFn;
+  Object.freeze(Clock);
+  Object.freeze(Clock.prototype);
   return Clock;
 };
 
@@ -8038,9 +8069,12 @@ getJasmineRequireObj().ParallelReportDispatcher = function(j$, private$) {
       for (const eventName of private$.reporterEvents) {
         this[eventName] = dispatcher[eventName].bind(dispatcher);
       }
+
+      Object.freeze(this);
     }
   }
 
+  Object.freeze(ParallelReportDispatcher.prototype);
   return ParallelReportDispatcher;
 };
 
@@ -11698,8 +11732,12 @@ getJasmineRequireObj().Timer = function() {
     this.elapsed = function() {
       return now() - startTime;
     };
+
+    Object.freeze(this);
   }
 
+  Object.freeze(Timer);
+  Object.freeze(Timer.prototype);
   return Timer;
 };