Description Andrea Guarinoni 2013-12-10 14:40:07 EST

In a theme plug-in, trying to import or use a resource into a CSS stylesheet throws a MalformedURLException at run-time when the '@import url()' is executed. Everything works with no errors when the plug-in is run/debugged into a second Eclipse instance and the package is build succesfully with no error or warning.

eg. if there is a project structure like:

> my.plugin.package.name
    > META-INF/
        > MANIFEST.MF
    > resources/
        > css/
            > base-stylesheet.css
            > win-stylesheet.css
            > linux-stylesheet.css
            > ...
        > images/
            > mytexture.png
            > ...
    > plugin.xml
    > ... 

And into 'linux-stylesheet.css' is imported 'base-stylesheet.css' and used 'mytexture.png':

    @import url("base-stylesheet.css");
    #elemId {
        background-image: url(mytexture.png);
    }

with a 'plugin.xml' like this:

    <?xml version="1.0" encoding="UTF-8"?>
    <?eclipse version="3.4"?>
    <plugin>
       <extension
             point="org.eclipse.e4.ui.css.swt.theme">
          <theme
               basestylesheeturi="resources/css/linux-stylesheet.css"
               id="my.plugin.id"
               label="Theme Name"
               os="linux">
          </theme>
          <theme
              ...
          </theme>
          <property
            name="applicationCSSResources" 
            value="platform:/plugin/my.plugin.id/resources/images/">        
          </property>
       </extension>
    </plugin>

if into CSS is used '@import url("platform:/plugin/my.plugin.id/resources/css/base-stylesheet.css")' where my.plugin.id is the Bundle-SymbolicName assigned in MANIFEST.MF we have the same error both when running/debugging the plugin and when using it after installing the jar.

Probably during plugin execution the workspace directory is automatically assigned to platform:/plugin/org.eclipse.platform/ and cannot be changed and the stylesheets placed into the same plugin directory are unreacheble by the @import.