selector-nest produces duplicates if parent selector consists of multiple parts

[Feuerfuchs]

To trigger this bug, just use a selector that consists of multiple parts (so something like .class1, .class2) as first argument for selector-nest. The function will act as if the parent selector contained all parts twice, and so the result consists of duplicates.

input.scss

.theme1, .theme2 {
  .something {
    /* nothing */
  }
}

$sel: selector-nest('.theme1, .theme2', '.something');
  
#{$sel} {
  /* nothing */
}

Actual results

libsass 3.5.4

.theme1 .something, .theme2 .something {
  /* nothing */
}

.theme1 .something, .theme2 .something, .theme1 .something, .theme2 .something {
  /* nothing */
}

Expected result

ruby sass 3.4.25

.theme1 .something, .theme2 .something {
  /* nothing */
}

.theme1 .something, .theme2 .something {
  /* nothing */
}

version info:

$ node-sass --version
node-sass       4.9.0   (Wrapper)       [JavaScript]
libsass         3.5.4   (Sass Compiler) [C/C++]

[glebm]

I'm not sure what fixed this but it is no longer broken on master:

$ sassc/bin/sassc ~/tmp/nest.scss
.theme1 .something, .theme2 .something {
  /* nothing */ }

.theme1 .something, .theme2 .something {
  /* nothing */ }

[xzyfer]

Spec added sass/sass-spec#1314

[xzyfer]

Test pass!