Rails: Sprockets::Rails::Helper::AssetNotPrecompiled in development

Question

I am relatively new to Rails and I am trying to use the asset pipeline, SCSS, in the development environment. However, after I created the controller, the view, and the css.scss file, I encounter the following error:

Sprockets::Rails::Helper::AssetNotPrecompiled

Here is the error message:

Asset was not declared to be precompiled in production. Add Rails.application.config.assets.precompile += %w( public.css ) to config/initializers/assets.rb and restart your server

I read that in development, the assets get compiled on the fly and there is no need to pre-compile. Why is there a pre-compile error? Did Rails think that I am in production instead of development?

Edited on 1 March 2016 ------

I just realized that adding files onto the config/initializers/assets.rb works. But is this the right way to do it? I have to add all the css/js/jpg files manually in the assets.rb for it to work. I felt that this somehow violate the DRY principle.

Mobile

Answer 1

Please check the file

config/environments/development.rb

config.assets.debug = true (if TRUE change to FALSE)

Seicento

config.assets.debug is set to True. – Mobile

try to change it to FALSE – Seicento

It worked. Thanks. So debug mode does not preprocess the assets, that's why i need to set it off? So the scss files require preprocessing to work? – Mobile

Welcome! Yes!, since it will takes time when its required to debug in development environment. But in production mode it is set to true, since you need to precompile all assets for faster rendering and interpreting. – Seicento

This didn't work for me I am still getting the error, I changed it from true to false – Humphries

Yeah, See Ameer's answer. It worked for me in Rails 5.2.5 https://mcmap.net/q/328752/-rails-sprockets-rails-helper-assetnotprecompiled-in-development – Influent

Answer 2

Neither of these worked for me (rails-5.0.7, sprockets-3.7.2, sprockets-rails-3.2.1):

config.assets.debug = false
config.assets.unknown_asset_fallback = true

But this did:

config.assets.check_precompiled_asset = false

Saturated

literally, config.assets.check_precompiled_asset worked for me too. rails version 4.2.8 – Neron

Thank you so much, this also worked for me in Rails 6.0.2.1 – Basion

This helped in api only app's issue in Apitome document parsing. – Gunter

This worked for me in rails 6.0.3.3 when Sprockets couldn't figure out myfile.js.erb was a thing – Pomeranian

Worked when rails 6 + spina failed out of the box (Oct 2020) – Evangelical

Worked for me, but why? App suddenly started throwing these errors for images. Chucking this in development.rb got it working again. – Nottage

only this worked for me Rails 5.2.6 (Oct 2021) – Mccabe

It works. But doesn't this mean, that it will not verify/check precompiled_assets ? Is it a good thing to do? – Forespeak

Thanks. I don't understand that, but Thanks! It worked for me. – Inquietude

Answer 3

I had the same problem and fixed it by deleting all the cache files inside the tmp folder

rm -rf tmp/cache/assets

Calciferous

This worked for me, thanks! (rails 5.2.2 / sprockets 4.0.2 / sprockets-rails 3.2.2) – Doriadorian

Thanks! This is the actual solution.rm -rf tmp/cache/assets/ – Thompson

Worked for me with Rails 6.1 – Ozell

Answer 4

//= link_directory ../javascripts .js

Adding this to app/assets/config/manifest.js
Worked for me (working on rails 6)

Pertussis

I had to add this two lines to make it work //= link administrate/application.css //= link administrate/application.js using Rails 6. – Leboeuf

Worked for me with rails 6.1.3 – Calmative

Answer 5

For those who came here after upgrading from rails 4 to 5-6 - checkout manifest.js

app/assets/config/manifest.js

If there is no link to js - just add one:

//= link_directory ../javascripts .js

Salmi

Answer 6

Changing assets.debug did not work for me in Rails v5.1.5. I had to use this option: config.assets.unknown_asset_fallback = true

Ultrasonics

Answer 7

you can initialize this scss file for the following line of code

Rails.application.config.assets.precompile += %w( applicationname.css )

Brent

file in which above needs to be changed: config/initializers/assets.rb – Mccabe

Answer 8

Try rake tmp:clear

References - https://github.com/rails/sprockets-rails/issues/458

Grugru

bingoding is right! ...that's the sound of relief – Campbellite

Answer 9

I needed to declare my assets in my manifest:

//= link_directory ../stylesheets .css

in app/assets/config/manifest.js

Millrace

Answer 10

Just adding here in case it might help someone.

I had a specific JS files I wanted only in a specific ActiveAdmin page and it was under /app/assets/javascripts/admin/orders.

Initially, none of the solutions worked for me beside adding this to config/environments/development.rb:

config.assets.check_precompiled_asset = false

A coworker mentioned that this change is a bit fishy and I tend to agree. Like what are the implications this will have on our development? Will we see errors related to precompilation of assets only in staging / prod from now?

Since I had subdirectories including JS files under my /app/assets/javascripts folder, I tried changing

//= link_directory ../javascripts .js

to

//= link_tree ../javascripts

And it solved it for me. Without the config.assets.check_precompiled_asset = false in the development.rb file.

Ratty

Answer 11

Add this to app/assets/config/manifest.js

//= link_directory ../javascripts .js

Leverrier

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Answer 12

Do not forget to restart the app too if you pulled new code.

Makedamakefast