Bug with null values and opacity

[talin-trulia]

Here's an odd case I've come across in carto compiling.

This style

#the_layer{
  polygon-fill: grey;
  [data_column = null] { polygon-fill: red; polygon-opacity: 0.5; }
  [data_column >= 100] { polygon-fill: blue; }
}

results in the XML

<Style name="the_layer" filter-mode="first" >
  <Rule>
    <Filter>([data_column] = null)</Filter>
    <PolygonSymbolizer fill="#0000ff" fill-opacity="0.5" />
  </Rule>
  <Rule>
    <Filter>([data_column] &gt;= 100)</Filter>
    <PolygonSymbolizer fill="#0000ff" />
  </Rule>
  <Rule>
    <PolygonSymbolizer fill="#808080" />
  </Rule>
</Style>

which is incorrect. data=null is being rendered as blue, when it should be rendered as red.

The style without polygon opacity

#the_layer{
  polygon-fill: grey;
  [data_column = null] { polygon-fill: red; }
  [data_column >= 100] { polygon-fill: blue; } 
}

results in correct XML

<Style name="the_layer" filter-mode="first" >
  <Rule>
    <Filter>([data_column] &gt;= 100)</Filter>
    <PolygonSymbolizer fill="#0000ff" />
  </Rule>
  <Rule>
    <Filter>([data_column] = null)</Filter>
    <PolygonSymbolizer fill="#ff0000" />
  </Rule>
  <Rule>
    <PolygonSymbolizer fill="#808080" />
  </Rule>
</Style>

Also, the style with opacity specified on both

#the_layer{
  polygon-fill: grey;
  [data_column = null] { polygon-fill: red; polygon-opacity: 0.5; }
  [data_column >= 100] { polygon-fill: blue; polygon-opacity: 0.75; }
}

compiles as expected

<Style name="the_layer" filter-mode="first" >
  <Rule>
    <Filter>([data_column] &gt;= 100)</Filter>
    <PolygonSymbolizer fill="#0000ff" fill-opacity="0.75" />
  </Rule>
  <Rule>
    <Filter>([data_column] = null)</Filter>
    <PolygonSymbolizer fill="#ff0000" fill-opacity="0.5" />
  </Rule>
  <Rule>
    <PolygonSymbolizer fill="#808080" />
  </Rule>
</Style>

This bug only occurs with [data_column = null]. using [data_column = 0] produces the expected output, even with only one specified polygon-opacity

#the_layer{
  polygon-fill: grey;
  [data_column = 0] { polygon-fill: red; polygon-opacity: 0.5; }
  [data_column >= 100] { polygon-fill: blue; }
}

<Style name="the_layer" filter-mode="first" >
  <Rule>
    <Filter>([data_column] &gt;= 100)</Filter>
    <PolygonSymbolizer fill="#0000ff" fill-opacity="0.75" />
  </Rule>
  <Rule>
    <Filter>([data_column] = null)</Filter>
    <PolygonSymbolizer fill="#ff0000" fill-opacity="0.5" />
  </Rule>
  <Rule>
    <PolygonSymbolizer fill="#808080" />
  </Rule>
</Style>

note: all compilations were done with a stub project.mml, and the carto binary installed with tilemill, version 0.4.7

edit: tested on 0.9.4, issue still exhibits.

[springmeyer]

@tmcw - I plan to dig into this next week to parse apart what might be js behavior, vs carto behavior, vs mapnik behavior.

[kapouer]

kapouer@721a6de, while not fixing every possible cases, shows where the problem is.

[springmeyer]

@kapouer - awesome, thanks for looking at this. As you can imagine, I've not found time to dig in yet.

[kapouer]

i figured i could help carto 0.9.5 out :)

[springmeyer]

don't have time to fix before v0.9.5 tag, pushing to v0.9.6

[springmeyer]

perhaps related: c1e8c3b