diff --git a/modules/kobalt-plugin-api/src/main/kotlin/com/beust/kobalt/api/ISourceDirectoryContributor.kt b/modules/kobalt-plugin-api/src/main/kotlin/com/beust/kobalt/api/ISourceDirectoryContributor.kt
index 29394d40..91ea96a0 100644
--- a/modules/kobalt-plugin-api/src/main/kotlin/com/beust/kobalt/api/ISourceDirectoryContributor.kt
+++ b/modules/kobalt-plugin-api/src/main/kotlin/com/beust/kobalt/api/ISourceDirectoryContributor.kt
@@ -8,3 +8,10 @@ import java.io.File
 interface ISourceDirectoryContributor {
     fun sourceDirectoriesFor(project: Project, context: KobaltContext): List<File>
 }
+
+fun KobaltContext.sourceDirectories(project: Project) : List<File> {
+    val result = pluginInfo.sourceDirContributors.flatMap {
+        it.sourceDirectoriesFor(project, this)
+    }
+    return result
+}
diff --git a/modules/kobalt-plugin-api/src/main/kotlin/com/beust/kobalt/api/Project.kt b/modules/kobalt-plugin-api/src/main/kotlin/com/beust/kobalt/api/Project.kt
index d2349bd7..98f0f67b 100644
--- a/modules/kobalt-plugin-api/src/main/kotlin/com/beust/kobalt/api/Project.kt
+++ b/modules/kobalt-plugin-api/src/main/kotlin/com/beust/kobalt/api/Project.kt
@@ -5,7 +5,6 @@ import com.beust.kobalt.api.annotation.Directive
 import com.beust.kobalt.internal.JvmCompilerPlugin
 import com.beust.kobalt.maven.dependency.MavenDependency
 import com.beust.kobalt.misc.KFiles
-import com.beust.kobalt.misc.log
 import java.io.File
 import java.util.*
 
@@ -25,27 +24,6 @@ open class Project(
         @Directive open var packageName: String? = group) : IBuildConfig {
 
     class ProjectExtra(project: Project) {
-        val suffixesFound : Set<String> by lazy {
-            val sf = hashSetOf<String>()
-            Kobalt.context?.let {
-                project.sourceDirectories.forEach { source ->
-                    val sourceDir = File(KFiles.joinDir(project.directory, source))
-                    if (sourceDir.exists()) {
-                        KFiles.findRecursively(sourceDir, { file ->
-                            val ind = file.lastIndexOf(".")
-                            if (ind >= 0) {
-                                sf.add(file.substring(ind + 1))
-                            }
-                            false
-                        })
-                    } else {
-                        log(2, "Skipping nonexistent directory $sourceDir")
-                    }
-                }
-            }
-            sf
-        }
-
         val dependsOn = arrayListOf<Project>()
 
         var isDirty = false
@@ -64,7 +42,8 @@ open class Project(
 
     val testConfigs = arrayListOf(TestConfig(this))
 
-    override var buildConfig : BuildConfig? = BuildConfig()
+    // If one is specified by default, we only generate a BuildConfig, find a way to fix that
+    override var buildConfig : BuildConfig? = null // BuildConfig()
 
     val projectProperties = ProjectProperties()
 
diff --git a/modules/kobalt-plugin-api/src/main/kotlin/com/beust/kobalt/internal/JvmCompilerPlugin.kt b/modules/kobalt-plugin-api/src/main/kotlin/com/beust/kobalt/internal/JvmCompilerPlugin.kt
index e85d003c..8c7da2c7 100644
--- a/modules/kobalt-plugin-api/src/main/kotlin/com/beust/kobalt/internal/JvmCompilerPlugin.kt
+++ b/modules/kobalt-plugin-api/src/main/kotlin/com/beust/kobalt/internal/JvmCompilerPlugin.kt
@@ -174,7 +174,11 @@ open class JvmCompilerPlugin @Inject constructor(
         } else {
             compilerContributors.forEach { contributor ->
                 contributor.compilersFor(project, context).forEach { compiler ->
-                    if (containsSourceFiles(project, compiler)) {
+                    val sourceFiles = KFiles.findSourceFiles(project,
+                            context.sourceDirectories(project).map { it.path }, compiler.sourceSuffixes)
+                    if (sourceFiles.size > 0) {
+                        // TODO: createCompilerActionInfo recalculates the source files, only compute them
+                        // once and pass them
                         val info = createCompilerActionInfo(project, context, isTest, sourceDirectories,
                                 sourceSuffixes = compiler.sourceSuffixes)
                         val thisResult = compiler.compile(project, context, info)
@@ -192,13 +196,6 @@ open class JvmCompilerPlugin @Inject constructor(
         }
     }
 
-    private fun containsSourceFiles(project: Project, compiler: ICompiler): Boolean {
-        project.projectExtra.suffixesFound.forEach {
-            if (compiler.sourceSuffixes.contains(it)) return true
-        }
-        return false
-    }
-
     val allProjects = arrayListOf<ProjectDescription>()
 
     override fun projects() = allProjects
@@ -270,7 +267,7 @@ open class JvmCompilerPlugin @Inject constructor(
             })
 
         // Transform them with the interceptors, if any
-        val sourceDirectories = if (isTest) {
+        val allSourceDirectories = if (isTest) {
             initialSourceDirectories
         } else {
             context.pluginInfo.sourceDirectoriesInterceptors.fold(initialSourceDirectories.toList(),
@@ -280,7 +277,7 @@ open class JvmCompilerPlugin @Inject constructor(
         }
 
         // Now that we have all the source directories, find all the source files in them
-        val sourceFiles = files.findRecursively(projectDirectory, sourceDirectories,
+        val sourceFiles = files.findRecursively(projectDirectory, allSourceDirectories,
                 { file -> sourceSuffixes.any { file.endsWith(it) }})
                 .map { File(projectDirectory, it).path }
 
diff --git a/modules/kobalt-plugin-api/src/main/kotlin/com/beust/kobalt/misc/KFiles.kt b/modules/kobalt-plugin-api/src/main/kotlin/com/beust/kobalt/misc/KFiles.kt
index 3d9028fb..3e18598a 100644
--- a/modules/kobalt-plugin-api/src/main/kotlin/com/beust/kobalt/misc/KFiles.kt
+++ b/modules/kobalt-plugin-api/src/main/kotlin/com/beust/kobalt/misc/KFiles.kt
@@ -284,6 +284,34 @@ class KFiles {
         fun isExcluded(file: File, excludes: List<Glob>) = isExcluded(file.path, excludes)
 
         fun isExcluded(file: String, excludes: List<Glob>): Boolean = excludes.any { it.matches(file) }
+
+        /**
+         * TODO: cache these per project so we don't do it more than once.
+         */
+        fun findSourceFiles(project: Project, sourceDirectories: Collection<String>,
+                suffixes: List<String>) : Set<String> {
+            val result = hashSetOf<String>()
+            Kobalt.context?.let {
+                sourceDirectories.forEach { source ->
+                    val sourceDir = File(KFiles.joinDir(project.directory, source))
+                    if (sourceDir.exists()) {
+                        KFiles.findRecursively(sourceDir, { file ->
+                            val ind = file.lastIndexOf(".")
+                            if (ind >= 0) {
+                                val suffix = file.substring(ind + 1)
+                                if (suffixes.contains(suffix)) {
+                                    result.add(file)
+                                }
+                            }
+                            false
+                        })
+                    } else {
+                        log(2, "Skipping nonexistent directory $sourceDir")
+                    }
+                }
+            }
+            return result
+        }
     }
 
     fun findRecursively(directory: File, function: Function1<String, Boolean>): List<String> {
diff --git a/src/main/kotlin/com/beust/kobalt/plugin/java/JavaPlugin.kt b/src/main/kotlin/com/beust/kobalt/plugin/java/JavaPlugin.kt
index c413b385..8a294453 100644
--- a/src/main/kotlin/com/beust/kobalt/plugin/java/JavaPlugin.kt
+++ b/src/main/kotlin/com/beust/kobalt/plugin/java/JavaPlugin.kt
@@ -6,6 +6,7 @@ import com.beust.kobalt.api.*
 import com.beust.kobalt.api.annotation.Directive
 import com.beust.kobalt.internal.BaseJvmPlugin
 import com.beust.kobalt.internal.JvmCompilerPlugin
+import com.beust.kobalt.misc.KFiles
 import com.beust.kobalt.misc.warn
 import java.io.File
 import javax.inject.Inject
@@ -21,7 +22,14 @@ class JavaPlugin @Inject constructor(val javaCompiler: JavaCompiler)
 
     override val name = PLUGIN_NAME
 
-    override fun accept(project: Project) = project.projectExtra.suffixesFound.contains("java")
+    override fun accept(project: Project) = hasSourceFiles(project)
+
+    // IBuildConfigContributor
+
+    private fun hasSourceFiles(project: Project)
+            = KFiles.findSourceFiles(project, project.sourceDirectories, listOf("java")).size > 0
+
+    override fun affinity(project: Project) = if (hasSourceFiles(project)) 1 else 0
 
     // IDocContributor
     override fun affinity(project: Project, context: KobaltContext) =
@@ -66,9 +74,6 @@ class JavaPlugin @Inject constructor(val javaCompiler: JavaCompiler)
     override fun testSourceDirectoriesFor(project: Project, context: KobaltContext)
         = project.sourceDirectoriesTest.map { File(it) }.toList()
 
-    // IBuildConfigContributor
-    override fun affinity(project: Project) = if (project.projectExtra.suffixesFound.contains("java")) 1 else 0
-
     override val buildConfigSuffix = compiler.sourceSuffixes[0]
 
     override fun generateBuildConfig(project: Project, context: KobaltContext, packageName: String,
diff --git a/src/main/kotlin/com/beust/kobalt/plugin/kotlin/KotlinPlugin.kt b/src/main/kotlin/com/beust/kobalt/plugin/kotlin/KotlinPlugin.kt
index 6a1288b4..21c65d98 100644
--- a/src/main/kotlin/com/beust/kobalt/plugin/kotlin/KotlinPlugin.kt
+++ b/src/main/kotlin/com/beust/kobalt/plugin/kotlin/KotlinPlugin.kt
@@ -8,6 +8,7 @@ import com.beust.kobalt.internal.BaseJvmPlugin
 import com.beust.kobalt.internal.JvmCompilerPlugin
 import com.beust.kobalt.maven.dependency.FileDependency
 import com.beust.kobalt.maven.dependency.MavenDependency
+import com.beust.kobalt.misc.KFiles
 import com.beust.kobalt.misc.KobaltExecutors
 import com.beust.kobalt.misc.log
 import com.beust.kobalt.misc.warn
@@ -26,7 +27,14 @@ class KotlinPlugin @Inject constructor(val executors: KobaltExecutors)
 
     override val name = PLUGIN_NAME
 
-    override fun accept(project: Project) = project.projectExtra.suffixesFound.contains("kt")
+    override fun accept(project: Project) = hasSourceFiles(project)
+
+    // IBuildConfigContributor
+
+    private fun hasSourceFiles(project: Project)
+            = KFiles.findSourceFiles(project, project.sourceDirectories, listOf("kt")).size > 0
+
+    override fun affinity(project: Project) = if (hasSourceFiles(project)) 1 else 0
 
     // IDocContributor
     override fun affinity(project: Project, context: KobaltContext) =
@@ -134,9 +142,6 @@ class KotlinPlugin @Inject constructor(val executors: KobaltExecutors)
         log(2, "${project.name}: $s")
     }
 
-    // IBuildConfigContributor
-    override fun affinity(project: Project) = if (project.projectExtra.suffixesFound.contains("kotlin")) 2 else 0
-
     override val buildConfigSuffix = "kt"
 
     override fun generateBuildConfig(project: Project, context: KobaltContext, packageName: String,