Handle wrongly implemented `DokkaMultiModuleFileLayout`

2 files changed, 39 insertions, 3 deletions

diff --git a/runners/gradle-plugin/src/main/kotlin/org/jetbrains/dokka/gradle/DokkaMultiModuleFileLayout.kt b/runners/gradle-plugin/src/main/kotlin/org/jetbrains/dokka/gradle/DokkaMultiModuleFileLayout.kt
index bb48ba2a..e3b82e7c 100644
--- a/runners/gradle-plugin/src/main/kotlin/org/jetbrains/dokka/gradle/DokkaMultiModuleFileLayout.kt
+++ b/runners/gradle-plugin/src/main/kotlin/org/jetbrains/dokka/gradle/DokkaMultiModuleFileLayout.kt
@@ -1,5 +1,6 @@
 package org.jetbrains.dokka.gradle
 
+import org.jetbrains.dokka.DokkaException
 import java.io.File
 
 /**
@@ -59,14 +60,25 @@ internal fun DokkaMultiModuleTask.copyChildOutputDirectory(child: AbstractDokkaT
     val targetChildOutputDirectory = project.file(fileLayout.targetChildOutputDirectory(this, child))
     val sourceChildOutputDirectory = child.outputDirectory.getSafe()
 
-    if (!sourceChildOutputDirectory.exists()) {
+    /* Pointing to the same directory -> No copy necessary */
+    if (sourceChildOutputDirectory.absoluteFile == targetChildOutputDirectory.absoluteFile) {
         return
     }
 
-    if (sourceChildOutputDirectory.absoluteFile == targetChildOutputDirectory.absoluteFile) {
+    /* Cannot target *inside* the original folder */
+    if (targetChildOutputDirectory.absoluteFile.startsWith(sourceChildOutputDirectory.absoluteFile)) {
+        throw DokkaException(
+            "Cannot re-locate output directory into itself.\n" +
+                    "sourceChildOutputDirectory=${sourceChildOutputDirectory.path}\n" +
+                    "targetChildOutputDirectory=${targetChildOutputDirectory.path}"
+        )
+    }
+
+    /* Source output directory is empty -> No copy necessary */
+    if (!sourceChildOutputDirectory.exists()) {
         return
     }
 
-    sourceChildOutputDirectory.copyRecursively(targetChildOutputDirectory, overwrite = false)
+    sourceChildOutputDirectory.copyRecursively(targetChildOutputDirectory, overwrite = true)
 }
 
diff --git a/runners/gradle-plugin/src/test/kotlin/org/jetbrains/dokka/gradle/DokkaMultiModuleFileLayoutTest.kt b/runners/gradle-plugin/src/test/kotlin/org/jetbrains/dokka/gradle/DokkaMultiModuleFileLayoutTest.kt
index 951e292f..6ec3dd57 100644
--- a/runners/gradle-plugin/src/test/kotlin/org/jetbrains/dokka/gradle/DokkaMultiModuleFileLayoutTest.kt
+++ b/runners/gradle-plugin/src/test/kotlin/org/jetbrains/dokka/gradle/DokkaMultiModuleFileLayoutTest.kt
@@ -2,11 +2,13 @@ package org.jetbrains.dokka.gradle
 
 import org.gradle.kotlin.dsl.create
 import org.gradle.testfixtures.ProjectBuilder
+import org.jetbrains.dokka.DokkaException
 import org.jetbrains.dokka.gradle.DokkaMultiModuleFileLayout.CompactInParent
 import org.jetbrains.dokka.gradle.DokkaMultiModuleFileLayout.NoCopy
 import java.io.File
 import kotlin.test.Test
 import kotlin.test.assertEquals
+import kotlin.test.assertFailsWith
 import kotlin.test.assertTrue
 
 class DokkaMultiModuleFileLayoutTest {
@@ -97,4 +99,26 @@ class DokkaMultiModuleFileLayoutTest {
             "Expected content to be written into 'other.file'"
         )
     }
+
+    @Test
+    fun `copyChildOutputDirectory target output directory within itself throws DokkaException`() {
+        val project = ProjectBuilder.builder().build()
+        val childTask = project.tasks.create<DokkaTask>("child")
+        val parentTask = project.tasks.create<DokkaMultiModuleTask>("parent")
+        parentTask.fileLayout = object : DokkaMultiModuleFileLayout {
+            override fun targetChildOutputDirectory(parent: DokkaMultiModuleTask, child: AbstractDokkaTask): File {
+                return child.outputDirectory.getSafe().resolve("subfolder")
+            }
+        }
+        assertFailsWith<DokkaException> { parentTask.copyChildOutputDirectory(childTask) }
+    }
+
+    @Test
+    fun `copyChildOutputDirectory NoCopy`() {
+        val project = ProjectBuilder.builder().build()
+        val childTask = project.tasks.create<DokkaTask>("child")
+        val parentTask = project.tasks.create<DokkaMultiModuleTask>("parent")
+        parentTask.fileLayout = NoCopy
+        parentTask.copyChildOutputDirectory(childTask)
+    }
 }