Merge pull request #1011 from medikoo/1122-improve-error-handling

Fix handling of multiple compilation errors

lib/compile.js

@@ -87,7 +87,7 @@ function webpackCompile(config, logStats, ServerlessError) {
     _.forEach(stats, compileStats => {
       logStats(compileStats);
       if (compileStats.hasErrors()) {
-        throw new ServerlessError('Webpack compilation error, see stats above');
+        throw _.assign(new ServerlessError('Webpack compilation error, see stats above'), { stats: compileStats });
       }
     });
 
@@ -99,9 +99,22 @@ function webpackCompile(config, logStats, ServerlessError) {
 }
 
 function webpackConcurrentCompile(configs, logStats, concurrency, ServerlessError) {
-  return BbPromise.map(configs, config => webpackCompile(config, logStats, ServerlessError), { concurrency }).then(
-    stats => _.flatten(stats)
-  );
+  const errors = [];
+  return BbPromise.map(
+    configs,
+    config =>
+      webpackCompile(config, logStats, ServerlessError).catch(error => {
+        errors.push(error);
+        return error.stats;
+      }),
+    { concurrency }
+  ).then(stats => {
+    if (errors.length) {
+      if (errors.length === 1) throw errors[0];
+      throw new ServerlessError('Webpack compilation errors, see stats above');
+    }
+    return _.flatten(stats);
+  });
 }
 
 module.exports = {