Compilation from source: LESS file is empty

Question

What is the reason behind the error as below:

Compilation from source: LESS file is empty: frontend/vendor/theme/en_GB/css/style.less

I am using a custom theme that inherits from the default blank theme. This error is getting logged in the exception.log file on every page accessed on the frontend. I even copied the _style.less file from blank theme into the custom theme and ran commands but the error persists.

Note: All the commands run fine without any error but still getting the above-mentioned error in exception.log

Answer 1

The solution was to place a file named "style.less" in my custom theme web/css folder. I am not sure why is this file necessary since all the CSS is inherited from the parent theme, so I just put one dummy class in it for now, will keep an eye if it's breaking any part of the theme.

Answer 2

I had similar issues on custom admin page, non of js and css files was loaded. I guess there was something with my injections. I did the recompilation bin/magento s:d:c and this did the trick and resolved the issue. Hope it will help someone who faced with same issues

Answer 3

I got a similar error when I was creating child theme from parent theme.

Compilation from source: /vendor/swissup/theme-frontend-breeze-blank/web/css/default.less
Compilation from source: LESS file is empty: frontend/Vendor/theme/en_US/css/default.less

This error was coming for me because I was using wrong parent theme name in my child theme.xml

<theme xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:Config/etc/theme.xsd">
    <title>New Magento 2</title>
    <parent>Swissup/breeze-evolution</parent>
    <media>
        <preview_image>media/preview.png</preview_image>
    </media>
</theme>

When I corrected to

<theme xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:Config/etc/theme.xsd">
    <title>New Magento 2</title>
     <parent>Swissup/argento-breeze-evolution</parent>
    <media>
        <preview_image>media/preview.png</preview_image>
    </media>
</theme>

the error was gone.