Empty modules filtering (#1699)

5 files changed, 36 insertions, 14 deletions

diff --git a/plugins/base/src/main/kotlin/DokkaBase.kt b/plugins/base/src/main/kotlin/DokkaBase.kt
index ac070ab4..938c7701 100644
--- a/plugins/base/src/main/kotlin/DokkaBase.kt
+++ b/plugins/base/src/main/kotlin/DokkaBase.kt
@@ -80,6 +80,12 @@ class DokkaBase : DokkaPlugin() {
         }
     }
 
+    val emptyModulesFilter by extending {
+        preMergeDocumentableTransformer with EmptyModulesFilterTransformer() order {
+            after(emptyPackagesFilter)
+        }
+    }
+
     val modulesAndPackagesDocumentation by extending {
         preMergeDocumentableTransformer providing ::ModuleAndPackageDocumentationTransformer
     }
diff --git a/plugins/base/src/main/kotlin/generation/SingleModuleGeneration.kt b/plugins/base/src/main/kotlin/generation/SingleModuleGeneration.kt
index 1689a1dd..9bf61af9 100644
--- a/plugins/base/src/main/kotlin/generation/SingleModuleGeneration.kt
+++ b/plugins/base/src/main/kotlin/generation/SingleModuleGeneration.kt
@@ -1,4 +1,3 @@
-
 package org.jetbrains.dokka.base.generation
 
 import kotlinx.coroutines.Dispatchers
@@ -32,6 +31,7 @@ class SingleModuleGeneration(private val context: DokkaContext) : Generation {
 
         report("Merging documentation models")
         val documentationModel = mergeDocumentationModels(transformedDocumentationBeforeMerge)
+            ?: exitGenerationGracefully("Nothing to document")
 
         report("Transforming documentation model after merging")
         val transformedDocumentation = transformDocumentationModelAfterMerge(documentationModel)
@@ -56,7 +56,8 @@ class SingleModuleGeneration(private val context: DokkaContext) : Generation {
     }
 
     fun transformDocumentationModelBeforeMerge(modulesFromPlatforms: List<DModule>) =
-        context.plugin<DokkaBase>().query { preMergeDocumentableTransformer }.fold(modulesFromPlatforms) { acc, t -> t(acc) }
+        context.plugin<DokkaBase>().query { preMergeDocumentableTransformer }
+            .fold(modulesFromPlatforms) { acc, t -> t(acc) }
 
     fun mergeDocumentationModels(modulesFromPlatforms: List<DModule>) =
         context.single(CoreExtensions.documentableMerger).invoke(modulesFromPlatforms)
@@ -99,7 +100,7 @@ class SingleModuleGeneration(private val context: DokkaContext) : Generation {
 
     private suspend fun translateSources(sourceSet: DokkaConfiguration.DokkaSourceSet, context: DokkaContext) =
         context[CoreExtensions.sourceToDocumentableTranslator].parallelMap { translator ->
-            when(translator){
+            when (translator) {
                 is AsyncSourceToDocumentableTranslator -> translator.invokeSuspending(sourceSet, context)
                 else -> translator.invoke(sourceSet, context)
             }
diff --git a/plugins/base/src/main/kotlin/renderers/DefaultRenderer.kt b/plugins/base/src/main/kotlin/renderers/DefaultRenderer.kt
index d76ba597..2694adc9 100644
--- a/plugins/base/src/main/kotlin/renderers/DefaultRenderer.kt
+++ b/plugins/base/src/main/kotlin/renderers/DefaultRenderer.kt
@@ -7,7 +7,6 @@ import kotlinx.coroutines.runBlocking
 import org.jetbrains.dokka.DokkaException
 import org.jetbrains.dokka.base.DokkaBase
 import org.jetbrains.dokka.base.resolvers.local.LocationProvider
-import org.jetbrains.dokka.base.resolvers.local.resolveOrThrow
 import org.jetbrains.dokka.model.DisplaySourceSet
 import org.jetbrains.dokka.pages.*
 import org.jetbrains.dokka.plugability.DokkaContext
@@ -169,12 +168,20 @@ abstract class DefaultRenderer<T>(
                 is RenderingStrategy.Copy -> outputWriter.writeResources(strategy.from, path)
                 is RenderingStrategy.Write -> outputWriter.write(path, strategy.text, "")
                 is RenderingStrategy.Callback -> outputWriter.write(path, strategy.instructions(this, page), ".html")
-                is RenderingStrategy.DriLocationResolvableWrite -> outputWriter.write(path, strategy.contentToResolve { dri, sourcesets ->
-                    locationProvider.resolve(dri, sourcesets)
-                }, "")
-                is RenderingStrategy.PageLocationResolvableWrite -> outputWriter.write(path, strategy.contentToResolve { pageToLocate, context ->
-                    locationProvider.resolve(pageToLocate, context)
-                }, "")
+                is RenderingStrategy.DriLocationResolvableWrite -> outputWriter.write(
+                    path,
+                    strategy.contentToResolve { dri, sourcesets ->
+                        locationProvider.resolve(dri, sourcesets)
+                    },
+                    ""
+                )
+                is RenderingStrategy.PageLocationResolvableWrite -> outputWriter.write(
+                    path,
+                    strategy.contentToResolve { pageToLocate, context ->
+                        locationProvider.resolve(pageToLocate, context)
+                    },
+                    ""
+                )
                 RenderingStrategy.DoNothing -> Unit
             }
             else -> throw AssertionError(
diff --git a/plugins/base/src/main/kotlin/transformers/documentables/DefaultDocumentableMerger.kt b/plugins/base/src/main/kotlin/transformers/documentables/DefaultDocumentableMerger.kt
index 4c931230..94e27424 100644
--- a/plugins/base/src/main/kotlin/transformers/documentables/DefaultDocumentableMerger.kt
+++ b/plugins/base/src/main/kotlin/transformers/documentables/DefaultDocumentableMerger.kt
@@ -12,9 +12,8 @@ import org.jetbrains.kotlin.utils.addToStdlib.firstNotNullResult
 internal class DefaultDocumentableMerger(val context: DokkaContext) : DocumentableMerger {
     private val dependencyInfo = context.getDependencyInfo()
 
-    override fun invoke(modules: Collection<DModule>): DModule {
-
-        return modules.reduce { left, right ->
+    override fun invoke(modules: Collection<DModule>): DModule? =
+        modules.reduceOrNull { left, right ->
             val list = listOf(left, right)
             DModule(
                 name = modules.map { it.name }.distinct().joinToString("|"),
@@ -26,7 +25,6 @@ internal class DefaultDocumentableMerger(val context: DokkaContext) : Documentab
                 sourceSets = list.flatMap { it.sourceSets }.toSet()
             ).mergeExtras(left, right)
         }
-    }
 
     private fun DokkaContext.getDependencyInfo()
             : Map<DokkaConfiguration.DokkaSourceSet, List<DokkaConfiguration.DokkaSourceSet>> {
diff --git a/plugins/base/src/main/kotlin/transformers/documentables/EmptyModulesFilterTransformer.kt b/plugins/base/src/main/kotlin/transformers/documentables/EmptyModulesFilterTransformer.kt
new file mode 100644
index 00000000..fa31c5c3
--- /dev/null
+++ b/plugins/base/src/main/kotlin/transformers/documentables/EmptyModulesFilterTransformer.kt
@@ -0,0 +1,10 @@
+package org.jetbrains.dokka.base.transformers.documentables
+
+import org.jetbrains.dokka.model.DModule
+import org.jetbrains.dokka.transformers.documentation.PreMergeDocumentableTransformer
+
+class EmptyModulesFilterTransformer : PreMergeDocumentableTransformer {
+    override fun invoke(modules: List<DModule>): List<DModule> {
+        return modules.filter { it.children.isNotEmpty() }
+    }
+}
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