Fix loading empty properties by CLI json parser.

core/src/main/kotlin/defaultConfiguration.kt

@@ -42,9 +42,9 @@ data class DokkaSourceSetImpl(
     override val skipEmptyPackages: Boolean = DokkaDefaults.skipEmptyPackages,
     override val skipDeprecated: Boolean = DokkaDefaults.skipDeprecated,
     override val jdkVersion: Int = DokkaDefaults.jdkVersion,
-    override val sourceLinks: Set<SourceLinkDefinitionImpl> = emptySet(),
-    override val perPackageOptions: List<PackageOptionsImpl> = emptyList(),
-    override val externalDocumentationLinks: Set<ExternalDocumentationLinkImpl> = emptySet(),
+    override val sourceLinks: Set<SourceLinkDefinitionImpl> = mutableSetOf(),
+    override val perPackageOptions: List<PackageOptionsImpl> = mutableListOf(),
+    override val externalDocumentationLinks: Set<ExternalDocumentationLinkImpl> = mutableSetOf(),
     override val languageVersion: String? = null,
     override val apiVersion: String? = null,
     override val noStdlibLink: Boolean = DokkaDefaults.noStdlibLink,

runners/cli/src/main/kotlin/cli/main.kt

@@ -288,7 +288,7 @@ private fun parseSourceSet(moduleName: String, args: Array<String>): DokkaConfig
         override val jdkVersion = jdkVersion
         override val sourceLinks = sourceLinks.toMutableSet()
         override val analysisPlatform = analysisPlatform
-        override val perPackageOptions = parsePerPackageOptions(perPackageOptions)
+        override val perPackageOptions = parsePerPackageOptions(perPackageOptions).toMutableList()
         override val externalDocumentationLinks = parseLinks(externalDocumentationLinks).toMutableSet()
         override val languageVersion = languageVersion
         override val apiVersion = apiVersion

runners/cli/src/test/kotlin/cli/CliTest.kt

@@ -27,4 +27,17 @@ class CliIntegrationTest {
 
     }
 
+    @Test
+    fun `should not fail when no sourceset options are specified`() {
+        val jsonPath = Paths.get(javaClass.getResource("/my-file-no-sourceset-options.json")?.toURI() ?: throw IllegalStateException("No JSON found!")).toFile().toString()
+        val globalArguments = GlobalArguments(arrayOf(jsonPath))
+
+        val configuration = initializeConfiguration(globalArguments)
+
+        configuration.sourceSets.forEach {
+            assertTrue(it.perPackageOptions.isEmpty())
+            assertTrue(it.sourceLinks.isEmpty())
+            assertTrue(it.externalDocumentationLinks.size == 2) // there are default values, java and kotlin stdlibs
+        }
+    }
 }

runners/cli/src/test/resources/my-file-no-sourceset-options.json

@@ -0,0 +1,13 @@
+{
+  "outputDir": "build/docs",
+  "sourceSets": [
+    {
+      "moduleDisplayName": "Sample",
+      "sourceSetID": {
+        "scopeId": "sample",
+        "sourceSetName": "main"
+      },
+      "sourceRoots": ["sample"]
+    }
+  ]
+}