How to Solve Circumvent Heroku’s x86_64 linux Error During Deployment

When I tried to deploy my Rails app to Heroku recently, I ran into a weird and frustrating error involving Heroku automatically adding x86_64-linux, which then led to a Node.js version mismatch and broke my asset precompilation step.

If you’re using Webpack or node sass in a Rails project and pushing to Heroku, you might hit the same problem. Here’s the story of how I identified, debugged, and fixed the issue and how you can too.

The Code That Trigger the Error

My project was pretty standard a Rails 6 app with some Webpack integration for styling. Here’s what my setup looked like.

package.json

{
  "name": "my-heroku-app",
  "version": "1.0.0",
  "scripts": {
    "build": "webpack --mode production"
  },
  "dependencies": {
    "node-sass": "^4.14.1"
  }
}

Gemfile

ruby '2.7.4'
gem 'rails', '~> 6.1.7'
gem 'sassc-rails'

.node-version and .ruby-version

# .node-version
14.15.5

# .ruby-version
2.7.4

Procfile

web: bundle exec puma -C config/puma.rb

The Problem

Even though I had clearly set Node 14.15.5 in .node-version, Heroku didn’t respect that by default. Instead, I saw this during deployment:

remote: -----> Installing node-v16.13.1-linux-x64

And then, boom the dreaded error during asset compilation:

error: ‘remove_cv_t’ is not a member of ‘std’; did you mean ‘remove_cv’?

This came from node-gyp, which is used to compile native bindings for node-sass. The C++ standard used by Node 16 was more strict, and that caused the error.

What Actually Cause It

Here’s the breakdown:

• Heroku installs Node 16.13.1 by default, unless you tell it otherwise.
• node-sass@4.14.1 doesn’t support Node 16 it supports up to Node 14.
• The native bindings in node-sass failed to compile under Node 16.
• That broke the asset pipeline, and the deployment failed.

The Fix

Specify Node and Yarn Versions in package.json

To make Heroku use the right versions, I added this:

"engines": {
  "node": "14.15.5",
  "yarn": "1.22.17"
}

This fixed the Heroku Node version mismatch.

Pin the Correct Buildpacks

I explicitly set the buildpacks via CLI:

heroku buildpacks:set heroku/nodejs
heroku buildpacks:add heroku/ruby

This ensures Node is installed before Ruby, which is necessary if you use Webpack or node-sass in your Rails project.

Replace node-sass with sass (Dart Sass)

Since node-sass is deprecated and uses native bindings (which is always fragile on Heroku), I just decided to move on:

npm uninstall node-sass
npm install sass

Dart Sass is written in JavaScript and doesn’t require compilation, so it’s much safer for deployment environments like Heroku.

Clean Node Modules and Cache

After making changes, I cleared everything to avoid leftover issues:

rm -rf node_modules
rm -rf yarn.lock package-lock.json
yarn install

Then I committed everything and redeployed:

git add .
git commit -m "Fix Heroku deploy: set node version and switch to sass"
git push heroku main

Add Environment Logging

To make sure I knew exactly what Heroku was using during build, I added a simple logging script:

log-env.js

console.log("Node Version:", process.version);
console.log("Platform:", process.platform);
console.log("Arch:", process.arch);

And updated the scripts in package.json:

"scripts": {
  "env-check": "node log-env.js",
  "build": "npm run env-check && webpack --mode production"
}

Add Node Version Check for Safety

I also added a version check script to prevent accidental installs on unsupported Node versions:

check-node-version.js

const [major] = process.versions.node.split('.').map(Number);
if (major > 14) {
  console.error(" Node version too high for node-sass 4.14.1");
  process.exit(1);
}

And in package.json:

"scripts": {
  "postinstall": "node check-node-version.js"
}

This saved me from future surprises if I ever reinstalled dependencies.

Summary

Step	Action
Set Node/Yarn	Use "engines" in package.json
Fix Buildpacks	Ensure NodeJS buildpack is before Ruby
Migrate	Replace node-sass with sass
Clean Cache	Clear node_modules and lockfiles
Add Logging	Track versions in build with log-env.js
Add Safety	Warn if Node version is too new

Final Thought

This whole issue was a great reminder that deployment environments don’t always match your local setup. Even when I had.node-version set correctly, Heroku ignored it and the node-sass version mismatch led to some deep C++ errors that seemed unrelated at first.