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Errors: Call the Plumber

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With gulp running, when we update a file, the gulp-bots recompile stuff for us. We're like a factory for CSS.

But there's a problem, a big problem if you're like me and mess up a lot. Add a syntax error in layout.scss.

Now check out gulp. It exploded! It's not even running anymore. So even if I fix the error, gulp is dead. I'll probably refresh my browser for 30 minutes before I realize that gulp hasn't been running this entire time. And I'll spend the next 5 minutes composing an angry tweet.

Out of the box, Gulp supports error handlers where you say "Hey, instead of exploding all crazy, just call this function over here." But instead, I'll show you a really nice plugin called gulp-plumber that'll take care of this for us.

Go look for gulp-plumber. Copy its handy install statement, and paste that to get it downloading.

npm install --save-dev gulp-plumber

Now, usually, this is where we'd go copy the require statement. But since we added gulp-load-plugins, we can skip that!

Instead, let's get to work. We need to pipe gulp through this plugin before any logic that might cause an error. So right after gulp.src, say pipe(plugins.plumber()):

30 lines gulpfile.js
... lines 1 - 11
.pipe(plugins.plumber(function(error) {
... lines 17 - 18
... lines 20 - 30


The function(error) callback function was not shown in the video, but should be included. This prevents an issue when running gulp watch.

And yea, that's it. Go back and get gulp back and running:


Let's mess up layout.scss again! This time, gulp does show us the error, it just doesn't die anymore. How nice! When we fix the error, it recompiles. Robots, get back to work!


Plumber prevents gulp from throwing a proper error exit code. When building for production, you may want a proper error. If so, try using plumber() only in development:

.pipe(gulpif(!util.env.production, plumber(function(error) {

Thanks to Nicolas Sauveur for the tip!

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Richard Avatar
Richard Avatar Richard | posted 5 years ago

This was one of those real "wow" days. How wonderful is gulp?


Hey Richard ,

Haha, we're going to release one more wonderful screencast: Webpack, which is even more wonderful for us, because we've switched from Gulp to Webpack on KnpU about six months ago ;)

Stay tuned!


Default user avatar
Default user avatar Marouane Rassili | posted 5 years ago

Hi, I'm using @import and partials. When I make a syntax error in one of the partials it doesn't throw an error!! It only throws an error when it detects a syntax error in the main scss file... That's so bad, please help


Hey Marouane,

Try to add "use strict" at the top of the JS file, does it help you? See https://www.w3schools.com/j... for more information.


Nicolas-S Avatar
Nicolas-S Avatar Nicolas-S | posted 5 years ago

Hello Ryan,

Just ran into an issue. Plumber seems to prevent gulp to throw the correct exit code when the script fails. It is problematic when you build assets for production in a deployment workflow, and gulp fails silently.

So I now use : .pipe(gulpif(!util.env.production, plumber()))

Default user avatar

When using plugins, it should be:

.pipe(plugins.if(!config.production, plumber()))


Hey Nicolas!

I like it a lot - very good point. I've added a note at the bottom of this chapter - thanks for sharing!


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What PHP libraries does this tutorial use?

// composer.json
    "require": {
        "php": ">=5.3.3",
        "symfony/symfony": "2.6.*", // v2.6.4
        "doctrine/orm": "~2.2,>=2.2.3", // v2.4.6
        "doctrine/doctrine-bundle": "~1.2", // v1.2.0
        "twig/extensions": "~1.0", // v1.2.0
        "symfony/assetic-bundle": "~2.3", // v2.5.0
        "symfony/swiftmailer-bundle": "~2.3", // v2.3.7
        "symfony/monolog-bundle": "~2.4", // v2.6.1
        "sensio/distribution-bundle": "~3.0", // v3.0.9
        "sensio/framework-extra-bundle": "~3.0", // v3.0.3
        "incenteev/composer-parameter-handler": "~2.0", // v2.1.0
        "hautelook/alice-bundle": "~0.2" // 0.2
    "require-dev": {
        "sensio/generator-bundle": "~2.3" // v2.4.0