async rendering patch broke some datasources

[artemp]

topojson, geojson and probably some more datasources are broken via async rendering patch.

I'm looking into it.

[springmeyer]

interesting. not seen this, but can imagine. perhaps something to due with datasources that cache features?

[artemp]

To reproduce

use multiple styles with geojson or topojson plugin e.g

<Layer name="topojson"
       srs="+proj=latlon +datum=WGS84" cache-features="false" >
  <StyleName>countries</StyleName>
  <StyleName>countries2</StyleName>
  <StyleName>labels</StyleName>
  <Datasource>
    <Parameter name="type"><![CDATA[topojson]]></Parameter>
    <Parameter name="file"><![CDATA[/Users/artem/Projects/topojson-parser/data/uk.json]]></Parameter>
  </Datasource>
</Layer>

Symptoms

intermittently missing features in output
enabling feature caching shadows this bug

Fix

Ensure featureset implementations never mutate state of the enclosing data source
topojson and geojson both need to be fixed to work correctly with async rendering

[artemp]

needs fixing in geojson and probably others plugins

[artemp]

fixed for topojson and geojson, closing

[lexman]

nice :)

[springmeyer]

re-opening and assigning to 2.3.x milestone since I need to backport a similar fix.

[springmeyer]

unable to reproduce any apparent problem with Mapnik 2.3.x + geojson plugin + multiple styles on a single layer.

[artemp]

@springmeyer - ^^ is this with 116706f or without ?

[springmeyer]

Without that backported to 2.3.x.

[springmeyer]

Nothing needing fixed anymore that I am aware of so closing.