Problem with search path for type-checking extensions

[chrylis]

I'm actively working on a type-checking extension, which is in the src/main/resources of my project. My class has @CompileStatic(extensions = 'my/extension.groovy'). This works correctly in the Maven CLI build and in Eclipse if I run Maven through at least process-resources, but using a Eclipse clean causes

Groovy:Static type checking extension 'my/extension.groovy' was not found on the classpath.

The problem appears to be a sequencing problem regarding resource access.

[eric-milles]

Can you share at least the structure of your project? Does eclipse recognize src/main/resources as a source folder? To get UI support, it needs to be a source folder and then you probably want a groovy script filter on it to prevent compilation. Let me know if you need help understanding how to set up those two things.

[chrylis]

It does recognize the folder as a source folder. I am not sure about the "Groovy script filter"; I was unaware of the concept until now.

[eric-milles]

Eclipse does not have the distinction of source and resource directories like Maven does. To have resources available through classpath, they must be source folders. Any groovy source unit in a source folder will be compiled, unless it is matched by a script filter. The m2e project configurator should probably apply a groovy script filter for any maven resource directory that is manifested as an eclipse source folder.

Update: the script filter sits between full exclusion and full inclusion. As-is a source folder includes all files. An exclusion can be set so eclipse ignores files matching a pattern; this prevents compilation but also prevents copying to output folder. Script filter can prevent compilation while still supporting copying of scripts to the output folder (for classpath inclusion).

[eric-milles]

I've used gradle to write script filters (see below). I think maven-eclipse-plugin can do a similar thing, if you are interested in automating configuration.

        apply plugin: 'eclipse'
        project.tasks.eclipse.doLast {
            if (!file("${project.projectDir}/.classpath").exists()) return

            file("${project.projectDir}/.settings/org.eclipse.jdt.groovy.core.prefs").with { prefs ->
                if (!prefs.exists()) {
                    append('''\
                        eclipse.preferences.version=1
                        groovy.compiler.level=40
                        groovy.script.filters=**/*.gradle,n,**/script*.groovy,y,**/*resources/**/*.groovy,y,**/benchmarks/**/*.groovy,y
                        org.codehaus.groovy.eclipse.preferences.compiler.project=true
                        '''.stripIndent()
                    )
                }
            }

[eric-milles]

I could look into changing the m2e project configurator to add script filters for resource directories. I'm not sure if m2e reapplies the configurator when you update a Maven project or if you would need to re-import the project. Thoughts?