From 18b58a9052217292ec713096fd1bf4876b9a273a Mon Sep 17 00:00:00 2001
From: Robert Jackson <rwjblue@twitch.tv>
Date: Wed, 10 Aug 2016 00:48:32 -0400
Subject: [PATCH] Support cache busting by AST plugins.

---
 ember-addon-main.js | 36 ++++++++++++++++++++++++++++++------
 package.json        |  1 +
 2 files changed, 31 insertions(+), 6 deletions(-)

diff --git a/ember-addon-main.js b/ember-addon-main.js
index f69ba3f1..8d37c88c 100644
--- a/ember-addon-main.js
+++ b/ember-addon-main.js
@@ -3,6 +3,7 @@
 var path = require('path');
 var checker = require('ember-cli-version-checker');
 var utils = require('./utils');
+var hashForDep = require('hash-for-dep');
 
 module.exports = {
   name: 'ember-cli-htmlbars',
@@ -90,6 +91,8 @@ module.exports = {
     delete require.cache[templateCompilerPath];
 
     global.EmberENV = EmberENV; // Needed for eval time feature flag checks
+    var pluginInfo = this.astPlugins();
+
     var htmlbarsOptions = {
       isHTMLBars: true,
       EmberENV: EmberENV,
@@ -97,8 +100,10 @@ module.exports = {
       templateCompilerPath: templateCompilerPath,
 
       plugins: {
-        ast: this.astPlugins()
-      }
+        ast: pluginInfo.plugins
+      },
+
+      pluginCacheKey: pluginInfo.cacheKeys
     };
 
     delete require.cache[templateCompilerPath];
@@ -110,10 +115,29 @@ module.exports = {
 
   astPlugins: function() {
     var pluginWrappers = this.parentRegistry.load('htmlbars-ast-plugin');
-    var plugins = pluginWrappers.map(function(wrapper) {
-      return wrapper.plugin;
-    });
+    var plugins = [];
+    var cacheKeys = [];
+
+    for (var i = 0; i < pluginWrappers.length; i++) {
+      var wrapper = pluginWrappers[i];
 
-    return plugins;
+      plugins.push(wrapper.plugin);
+
+      if (typeof wrapper.baseDir === 'function') {
+        var pluginHashForDep = hashForDep(wrapper.baseDir());
+        cacheKeys.push(pluginHashForDep);
+      } else {
+        // support for ember-cli < 2.2.0
+        var log = this.ui.writeDeprecateLine || this.ui.writeLine;
+
+        log.call(this.ui, 'ember-cli-htmlbars is opting out of caching due to an AST plugin that does not provide a caching strategy: `' + wrapper.name + '`.');
+        cacheKeys.push((new Date()).getTime() + '|' + Math.random());
+      }
+    }
+
+    return {
+      plugins: plugins,
+      cacheKeys: cacheKeys
+    };
   }
 };
diff --git a/package.json b/package.json
index 600df182..d15d57ce 100644
--- a/package.json
+++ b/package.json
@@ -40,6 +40,7 @@
   "dependencies": {
     "broccoli-persistent-filter": "^1.0.3",
     "ember-cli-version-checker": "^1.0.2",
+    "hash-for-dep": "^1.0.2",
     "json-stable-stringify": "^1.0.0",
     "strip-bom": "^2.0.0"
   }