Make cacheKey calculation lazy

index.js

@@ -78,12 +78,19 @@ module.exports = {
             parallelConfig
           }
         };
-        // parallelBabelInfo will not be used in the cache unless it is explicitly included
-        let cacheKey = AstPlugins.makeCacheKey(templateCompilerPath, pluginInfo, JSON.stringify(parallelBabelInfo));
+
+        let cacheKey;
         babelPlugins.push({
           _parallelBabel: parallelBabelInfo,
           baseDir: () => __dirname,
-          cacheKey: () => cacheKey,
+          cacheKey: () => {
+            if (cacheKey === undefined) {
+              // parallelBabelInfo will not be used in the cache unless it is explicitly included
+              cacheKey = AstPlugins.makeCacheKey(templateCompilerPath, pluginInfo, JSON.stringify(parallelBabelInfo));
+            }
+
+            return cacheKey;
+          },
         });
       }
       else {

lib/ast-plugins.js

@@ -53,15 +53,21 @@ module.exports = {
     global.EmberENV = clonedEmberENV;
 
     let Compiler = require(templateCompilerPath);
-    let cacheKey = this.makeCacheKey(templateCompilerPath, pluginInfo);
+    let cacheKey;
 
     let precompileInlineHTMLBarsPlugin;
 
     pluginInfo.plugins.forEach((plugin) => Compiler.registerPlugin('ast', plugin));
 
     let precompile = Compiler.precompile;
     precompile.baseDir = () => path.resolve(__dirname, '..');
-    precompile.cacheKey = () => cacheKey;
+    precompile.cacheKey = () => {
+      if (cacheKey === undefined) {
+        cacheKey = this.makeCacheKey(templateCompilerPath, pluginInfo);
+      }
+
+      return cacheKey;
+    };
 
     let modulePaths = ['ember-cli-htmlbars-inline-precompile', 'htmlbars-inline-precompile'];
     precompileInlineHTMLBarsPlugin = [HTMLBarsInlinePrecompilePlugin, { precompile, modulePaths }];