roads.mss carto code style error

[pnorman]

At line 1342

    [feature = 'highway_residential'],
    [feature = 'highway_unclassified'] {
      [zoom = 12][feature = 'highway_residential'] {
        line-color: @unimportant-road;
        line-width: 0.4;
      }
      [zoom = 12][feature = 'highway_unclassified'] {
        line-color: @unimportant-road;
        line-width: 1;
      }

zoom = should never be used

[matthijsmelissen]

Might be a nice exercise for people new to contributing.

[jojo4u]

I tried, but i also included my changes from another of my branches (simplify-capital). Yes git is not that easy... Will try again!
master...jojo4u:road-zoom (deleted)

[nebulon42]

In this particular case I see no sense in enforcing this. While the gist of the rule is to prevent style problems if higher/lower zooms are left out here the next rule anyway starts with zoom >= 13.

What sense does it make to change

[zoom = 12][feature = 'highway_residential'] {
  line-color: @unimportant-road;
  line-width: 0.4;
}
[zoom = 12][feature = 'highway_unclassified'] {
  line-color: @unimportant-road;
  line-width: 1;
}
[zoom >= 13] {

to

[zoom >= 12][zoom < 13][feature = 'highway_residential'] {
  line-color: @unimportant-road;
  line-width: 0.4;
}
[zoom >= 12][zoom < 13][feature = 'highway_unclassified'] {
  line-color: @unimportant-road;
  line-width: 1;
}
[zoom >= 13] {

I'm against dogmatic applying of style rules.

[matthijsmelissen]

See #410 for the previous time we had this discussion. I personally have no strong opinion either way.

[pnorman]

The standard way to write the logic here is

[feature = 'highway_residential'],
[feature = 'highway_unclassified'] {
  [zoom >= 12] {
    [feature = 'highway_residential'] { ... }
    [feature = 'highway_unclassified'] { ... }
  }
  [zoom >= 13] { ... }
  ...
}

[matkoniecz]

Note that it is done this way in part because proper way (presented in the comment above) resulted in a weird glitch.

At that time a glitch was appearing solely in TileMill (but not if export to file was used). Due to poor reproducibility I never successfully tracked down whatever it was truly caused by this change and whatever it was bug in style code or in Tilemill or in something else.

For this reason I will will remove "easy" label - if there is really something fishy going here it may be a poor introduction.