The «.less» extension can be skipped in the Less @import statements

dmitry_fedyuk · November 21, 2015, 1:39pm

@import 'order/_address';

is the same as

@import 'order/_address.less';

It matches the Less language specification: http://lesscss.org/features/#import-directives-feature-file-extensions
For some reason, Magento 2 core never uses the possibility to skip the *.less extension in @import calls.

How does it work:

github.com

magento/magento2/blob/2.0.0/lib/internal/Magento/Framework/Css/PreProcessor/Instruction/Import.php#L141-L156


/**
 * Resolve extension of imported asset according to exact format
 *
 * @param string $fileId
 * @param string $contentType
 * @return string
 * @link http://lesscss.org/features/#import-directives-feature-file-extensions
 */
protected function fixFileExtension($fileId, $contentType)
{
    if (!pathinfo($fileId, PATHINFO_EXTENSION)) {
        $fileId .= '.' . $contentType;
    }
    return $fileId;
}
}