Bugfix/bco#77 review protobuf merge from usage to avoid list entry dublication

module/extension/protobuf/src/main/java/org/openbase/jul/extension/protobuf/ProtoBufBuilderProcessor.kt

@@ -426,5 +426,41 @@ object ProtoBufBuilderProcessor {
         }
     }
 
+    /**
+     * This method clears all repeated fields from the given message before the `mergeFrom` is performed.
+     * This functionality can be useful, since `mergeFrom` would always duplicate all repeated fields
+     * which can be avoided by using this function instead.
+     * @param message the message to merge from.
+     */
+    @JvmStatic
+    fun <MB : Message.Builder> MB.mergeFromWithoutRepeatedFields(builder: Message.Builder): MB =
+        // we should not modify the passed builder, so we need to transform it into a message first.
+        mergeFromWithoutRepeatedFields(builder.build())
+
+    /**
+     * This method clears all repeated fields from the given message before the `mergeFrom` is performed.
+     * This functionality can be useful, since `mergeFrom` would always duplicate all repeated fields
+     * which can be avoided by using this function instead.
+     * @param message the message to merge from.
+     */
+    @JvmStatic
+    fun <MB : Message.Builder> MB.mergeFromWithoutRepeatedFields(message: Message): MB =
+        message.toBuilder()
+            .let { messageBuilder -> messageBuilder.clearRepeatedFields() }
+            .let { messageBuilder -> mergeFrom(messageBuilder.build()) as MB }
 
+    /**
+     * This method recursively clears all repeated fields from the builder instance.
+     */
+    @JvmStatic
+    fun <MB : Message.Builder> MB.clearRepeatedFields(): MB = also { builder ->
+        allFields.keys.forEach { descriptor ->
+            descriptor
+                .takeIf { it.isRepeated }
+                ?.also {clearField(it) ; return@forEach }
+            descriptor
+                .takeIf { it.javaType == Descriptors.FieldDescriptor.JavaType.MESSAGE }
+                ?.also { builder.getFieldBuilder(it).clearRepeatedFields() }
+        }
+    }
 }

module/extension/protobuf/src/test/java/org/openbase/jul/extension/protobuf/ProtoBufBuilderProcessorTest.kt

@@ -0,0 +1,65 @@
+package org.openbase.jul.extension.protobuf
+
+import io.kotest.matchers.comparables.shouldBeEqualComparingTo
+import io.kotest.matchers.ints.shouldBeExactly
+import org.junit.jupiter.api.Test
+
+import org.openbase.jul.extension.protobuf.ProtoBufBuilderProcessor.clearRepeatedFields
+import org.openbase.jul.extension.protobuf.ProtoBufBuilderProcessor.mergeFromWithoutRepeatedFields
+import org.openbase.type.domotic.action.ActionDescriptionType.ActionDescription
+import org.openbase.type.language.MultiLanguageTextType.MultiLanguageText
+
+internal class ProtoBufBuilderProcessorTest {
+
+    companion object {
+        private const val DE = "de"
+        private const val EN = "en"
+        private const val ES = "es"
+        private const val EN_DOG = "dog"
+        private const val DE_DOG = "hund"
+        private const val ES_DOG = "perro"
+    }
+
+    @Test
+    fun `should remove repeated fields` () {
+        ActionDescription.newBuilder().also {
+            it.descriptionBuilder.addAllEntry(
+                mutableListOf(
+                    MultiLanguageText.MapFieldEntry.newBuilder().setKey(DE).setValue(DE_DOG).build(),
+                    MultiLanguageText.MapFieldEntry.newBuilder().setKey(EN).setValue(EN_DOG).build(),
+                    MultiLanguageText.MapFieldEntry.newBuilder().setKey(ES).setValue(ES_DOG).build(),
+                )
+            ).build()
+        }.clearRepeatedFields().apply {
+            descriptionBuilder.entryCount shouldBeExactly 0
+        }
+    }
+
+    @Test
+    fun `should only merge from non-repeated fields`() {
+        val originBuilder = ActionDescription.newBuilder().also {
+            it.descriptionBuilder.addAllEntry(
+                mutableListOf(
+                    MultiLanguageText.MapFieldEntry.newBuilder().setKey(DE).setValue(DE_DOG).build(),
+                    MultiLanguageText.MapFieldEntry.newBuilder().setKey(EN).setValue(EN_DOG).build(),
+                )
+            ).build()
+        }
+
+        val builderToMerge = ActionDescription.newBuilder().also {
+            it.descriptionBuilder.addAllEntry(
+                mutableListOf(
+                    MultiLanguageText.MapFieldEntry.newBuilder().setKey(ES).setValue(ES_DOG).build(),
+                )
+            ).build()
+        }
+
+        originBuilder.mergeFromWithoutRepeatedFields(builderToMerge).apply {
+            descriptionBuilder.entryCount shouldBeExactly 2
+            descriptionBuilder.entryBuilderList[0].key shouldBeEqualComparingTo DE
+            descriptionBuilder.entryBuilderList[0].value shouldBeEqualComparingTo DE_DOG
+            descriptionBuilder.entryBuilderList[1].key shouldBeEqualComparingTo EN
+            descriptionBuilder.entryBuilderList[1].value shouldBeEqualComparingTo EN_DOG
+        }
+    }
+}