---
title: "Analyzing SassC::SyntaxError in Ruby on Rails 7.0"
description: "Analyze and fix SassC::SyntaxError in a current Ruby on Rails 7.0 project."
url: "https://qameta.com/posts/analyzing-sassc-syntax-error-in-ruby-on-rails-7-0/"
image: "https://qameta.com/posts/analyzing-sassc-syntax-error-in-ruby-on-rails-7-0/rails-sassc-syntaxerror.png"
---

# Analyzing SassC::SyntaxError in Ruby on Rails 7.0

![SassC::SyntaxError in Ruby on Rails](https://qameta.com/posts/analyzing-sassc-syntax-error-in-ruby-on-rails-7-0/rails-sassc-syntaxerror.png)

I was running a up to date Ruby on Rails 7.0 project using
[cssbundling-rails](https://github.com/rails/cssbundling-rails). The project was
in production for several months. After pushing the code to [Continuous
Integration (CI)](https://en.wikipedia.org/wiki/Continuous_integration) using
[GitHub Actions](https://docs.github.com/en/actions) it failed with an error:

```sh
$ sass ./app/assets/stylesheets/application.bootstrap.scss:./app/assets/builds/application.css --no-source-map --load-path=node_modules
Done in 3.38s.
rails aborted!
SassC::SyntaxError: Error: "var(--ts-pr-min)" is not a number for `max'
        on line 18581:18 of stdin, in function `max`
        from line 18581:18 of stdin
>>   padding-right: max(var(--ts-pr-min), var(--ts-pr-clear-button) + var(--ts-
   -----------------^
```

It was not failing on development machine. What was wrong?

## Analyzing the problem

The first thing I saw was, that compiling my project scss file using sass
command worked like expected, but than it failed later using
[sassc](https://rubygems.org/gems/sassc), which was not meant to be used in this
project.

### Why is sassc part of the project?

I've checked the `Gemfile` of the project for any sass gems, but couldn't find
any. It has to be a dependency from another gem I was using. After checking the
`Gemfile.lock` of the project, I could identify the
[administrate gem](https://rubygems.org/gems/administrate) having
[sassc-rails](https://rubygems.org/gems/sassc-rails) as dependency:

```txt
administrate (0.18.0)
  actionpack (>= 5.0)
  actionview (>= 5.0)
  activerecord (>= 5.0)
  jquery-rails (>= 4.0)
  kaminari (>= 1.0)
  sassc-rails (~> 2.1)
  selectize-rails (~> 0.6)
```

As these dependencies are part of the administrate gem and I was using
administrate in the project. I had to find a solution.

### Why is sassc being used in my asset pipeline at all?

I've checked the documentation of
[sassc-rails](https://github.com/sass/sassc-rails) gem and could remember, that
sprockets will use it or the predecessor
[sass-rails](https://github.com/rails/sass-rails) by default, if it was added to
a [Ruby on Rails](https://rubyonrails.org) project.

### How to disable it in sprockets?

As sprockets is using it by default in the assets pipeline and it was hitting
**test** environment, there should be an option to set the processor for CSS.
I've checked `config/environments/test.rb` and could find this entry, which was
not active:

```rb
# Compress CSS using a preprocessor.
# config.assets.css_compressor = :sass
```

As it was not active, it must be using some **convention over configuration** in
setup. To disable any explicit processor for CSS, it must  be set to nil in
`config/environments/test.rb` and `config/environments/production.rb`:

```diff
# Compress CSS using a preprocessor.
+ # Set it to nil to turn off sprockets CSS compression
- # config.assets.css_compressor = :sass
+ config.assets.css_compressor = nil
```

This won't stop administrate using the required gem, but will stop sprockets do
any compression of already compressed **css**, **sass** and **scss** files in
project.

## Why is sassc-rails still used in administrate?

I've checked [administrate](https://rubygems.org/gems/administrate) for any
[open issues related to
sass](https://github.com/thoughtbot/administrate/issues?q=is%3Aissue+is%3Aopen+sass)
and could find some.

There is also an [open issue
2311](https://github.com/thoughtbot/administrate/issues/2311) targeting the
problem. There is also a [pull
request](https://github.com/thoughtbot/administrate/pull/2388) which have the
changes to migrate the administrate gem from
[sassc-rails](https://rubygems.org/gems/sassc-rails) to
[dartsass-sprockets](https://rubygems.org/gems/dartsass-sprockets). After I've
checked all the issues and comments, I could see, that there was no
fast solution to get rid of old dependencies in administrate gem.

## Summary

Sometimes things work, even if you haven't setup them like it was running. Take
time to review your project setup to catch such hidden errors. As Ruby on Rails
have a good documentation, a lot of online content and many ways to use it, I
could find a solution without removing or changing anything on the administrate
gem to get it working.