Undefined property: Less_Tree_Color::$value

[gerardreches]

I get an _Undefined property: Less_TreeColor::$value exception with this code:

@black: #000000;
@white: #ffffff;
@color_list: black, white;

.generate-color-system(length(@color_list));

.generate-color-system(@number, @i: 1) when (@i =< @number) {
    @name: extract(@color_list, @i);

    .bg-@{name} { background-color: @@name; }

    .generate-color-system(@number, (@i + 1));
}

This code is compiled correctly at lesscss.org demo but not in my project and neither on less.php demo (here it throws variable @ is undefined).

Am I missing something? Is there a workaround?

EDIT: If I change background-color: @@name; to background-color: @name; it works on less.php but not in Less.

[seven-phases-max]

In Less before v2.x, the color keywords (i.e .black and white in your example) were always interpreted as actual color values (and never as generic identifiers). For more details see https://github.com/less/less.js/issues/1595.

Workaround: use escaping, e.g. ~'black' and ~'white'.

[gerardreches]

Thanks Max :+1: So less.php compiles in a previous version than 2.x ?

[seven-phases-max]

It's (the latest version) less or more equal to 1.7.x (actually its version -> Less version + "build number").

[dhduc]

I've compiled LESS on Magento 2, the bug happens when using @@variable instead of right way is @variable.

[kevnk]

I got this error in Magento 2 when I call a LESS function and passed in a variable without making it a string: escape(@variable) caused an error; escape("@{variable}") removed the error