fix: store grounded events in an adapted Java session service

PiperOrigin-RevId: 1007316424

Author: damianmomotgoogle

tokt/src/main/kotlin/com/google/adk/tokt/codecs/GroundingMetadataCodec.kt

@@ -49,7 +49,7 @@ internal object GroundingMetadataCodec {
   /** Returns the Kotlin [KtGroundingMetadata] view of the genai [metadata]. */
   fun fromJava(metadata: GenaiGroundingMetadata): KtGroundingMetadata =
     KtGroundingMetadata(
-      imageSearchQueries = metadata.imageSearchQueries().getOrNull().orEmpty(),
+      imageSearchQueries = metadata.imageSearchQueries().getOrNull(),
       groundingChunks = metadata.groundingChunks().getOrNull()?.map { chunkFromJava(it) },
       groundingSupports = metadata.groundingSupports().getOrNull()?.map { supportFromJava(it) },
       webSearchQueries = metadata.webSearchQueries().getOrNull(),
@@ -62,7 +62,8 @@ internal object GroundingMetadataCodec {
 
   /** Returns the genai [GenaiGroundingMetadata] view of the Kotlin [metadata]. */
   fun toJava(metadata: KtGroundingMetadata): GenaiGroundingMetadata {
-    val builder = GenaiGroundingMetadata.builder().imageSearchQueries(metadata.imageSearchQueries)
+    val builder = GenaiGroundingMetadata.builder()
+    metadata.imageSearchQueries?.let { builder.imageSearchQueries(it) }
     metadata.groundingChunks?.let { builder.groundingChunks(it.map { c -> chunkToJava(c) }) }
     metadata.groundingSupports?.let { builder.groundingSupports(it.map { s -> supportToJava(s) }) }
     metadata.webSearchQueries?.let { builder.webSearchQueries(it) }

tokt/src/test/kotlin/com/google/adk/tokt/KtRunnerInteropTest.kt

@@ -64,6 +64,7 @@ import com.google.adk.kt.types.GenerationConfigRoutingConfig as KtRoutingConfig
 import com.google.adk.kt.types.GenerationConfigRoutingConfigManualRoutingMode as KtManualRoutingMode
 import com.google.adk.kt.types.GoogleMaps as KtGoogleMaps
 import com.google.adk.kt.types.GoogleSearch as KtGoogleSearch
+import com.google.adk.kt.types.GroundingMetadata as KtGroundingMetadata
 import com.google.adk.kt.types.HarmBlockMethod as KtHarmBlockMethod
 import com.google.adk.kt.types.HarmBlockThreshold as KtHarmBlockThreshold
 import com.google.adk.kt.types.HarmCategory as KtHarmCategory
@@ -4552,6 +4553,24 @@ class KtRunnerInteropTest {
     assertEquals("places/abc", maps.placeId().getOrNull(), "maps chunk placeId")
   }
 
+  @Test
+  fun asKtSessionService_groundingMetadata_survivesTheJavaStore() = runBlocking {
+    // Kotlin's Gemini leaves imageSearchQueries unset on a Google Search answer.
+    val sessions = JavaAdkToKt.asKtSessionService(JavaInMemorySessionService())
+    val key = KtSessionKey("app", "u", "s")
+    val session = sessions.createSession(key)
+    val webSearch = KtGroundingMetadata(webSearchQueries = listOf("tallest building"))
+    val imageSearch = KtGroundingMetadata(imageSearchQueries = listOf("cat"))
+
+    for (grounding in listOf(webSearch, imageSearch)) {
+      val unused =
+        sessions.appendEvent(session, KtEvent(author = "model", groundingMetadata = grounding))
+    }
+
+    val stored = assertNotNull(sessions.getSession(key)).events.map { it.groundingMetadata }
+    assertEquals(listOf(webSearch, imageSearch), stored)
+  }
+
   @Test
   fun asKtSessionService_listEvents_carriesNextPageToken() = runBlocking {
     // The listEvents bridge must carry nextPageToken, or a paged Java service's continuation token