From 2a7f1d63685ec58a70ac076805e0d3df69d52da4 Mon Sep 17 00:00:00 2001
From: Raghu Simha <rsimha@ampproject.org>
Date: Mon, 5 Feb 2018 17:47:46 -0500
Subject: [PATCH] Fail build on error, and print a useful message (#13255)

---
 gulpfile.js | 9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/gulpfile.js b/gulpfile.js
index 7247fc26f2b9..7a1305558050 100644
--- a/gulpfile.js
+++ b/gulpfile.js
@@ -992,11 +992,10 @@ function compileJs(srcDir, srcFilename, destDir, options) {
     const startTime = Date.now();
     return toPromise(bundler.bundle()
       .on('error', function(err) {
-        if (err instanceof SyntaxError) {
-          console.error(red('Syntax error: ' + err.message));
-        } else {
-          console.error(red(err.message));
-        }
+        // Drop the node_modules call stack, which begins with '    at'.
+        const message = err.stack.replace(/    at[^]*/, '').trim();
+        console.error(red(message));
+        process.exit(1);
       })
       .pipe(lazybuild())
       .pipe($$.rename(destFilename))