Cache feature resolution state to avoid potential O(n^2) work. Features should never change

Author: mkruskal-google

src/object.js

@@ -67,6 +67,12 @@ function ReflectionObject(name, options) {
      */
     this._features = {};
 
+    /**
+     * Whether or not features have been resolved.
+     * @type {boolean}
+     * /
+    this._featuresResolved = false;
+
     /**
      * Parent namespace.
      * @type {Namespace|null}
@@ -173,7 +179,6 @@ ReflectionObject.prototype.resolve = function resolve() {
     if (this.resolved)
         return this;
     if (this instanceof Root) {
-        this._resolveFeaturesRecursive(this._edition);
         this.resolved = true;
     }
     return this;
@@ -194,6 +199,10 @@ ReflectionObject.prototype._resolveFeaturesRecursive = function _resolveFeatures
  * @returns {undefined}
  */
 ReflectionObject.prototype._resolveFeatures = function _resolveFeatures(edition) {
+    if (this._featuresResolved) {
+        return;
+    }
+
     var defaults = {};
 
     /* istanbul ignore if */
@@ -217,6 +226,7 @@ ReflectionObject.prototype._resolveFeatures = function _resolveFeatures(edition)
             throw new Error("Unknown edition: " + edition);
         }
         this._features = Object.assign(defaults, protoFeatures || {});
+        this._featuresResolved = true;
         return;
     }
 
@@ -238,6 +248,7 @@ ReflectionObject.prototype._resolveFeatures = function _resolveFeatures(edition)
         // Sister fields should have the same features as their extensions.
         this.extensionField._features = this._features;
     }
+    this._featuresResolved = true;
 };
 
 /**

src/root.js

@@ -272,6 +272,7 @@ Root.prototype.resolveAll = function resolveAll() {
         throw Error("unresolvable extensions: " + this.deferred.map(function(field) {
             return "'extend " + field.extend + "' in " + field.parent.fullName;
         }).join(", "));
+    this._resolveFeaturesRecursive(this._edition);
     return Namespace.prototype.resolveAll.call(this);
 };