Fix #5466: preserve text content in mixed-modality Gemini responses

models/spring-ai-google-genai/src/main/java/org/springframework/ai/google/genai/GoogleGenAiChatModel.java

@@ -646,15 +646,19 @@ protected List<Generation> responseCandidateToGeneration(Candidate candidate) {
 			.finishReason(candidateFinishReason.toString())
 			.build();
 
-		boolean isFunctionCall = candidate.content().isPresent() && candidate.content().get().parts().isPresent()
-				&& candidate.content().get().parts().get().stream().anyMatch(part -> part.functionCall().isPresent());
-
-		if (isFunctionCall) {
-			List<AssistantMessage.ToolCall> assistantToolCalls = candidate.content()
-				.get()
-				.parts()
-				.orElse(List.of())
-				.stream()
+		// Collect text parts
+		String textContent = "";
+		if (candidate.content().isPresent() && candidate.content().get().parts().isPresent()) {
+			textContent = candidate.content().get().parts().get().stream()
+				.filter(part -> part.text().isPresent())
+				.map(part -> part.text().get())
+				.collect(Collectors.joining(" "));
+		}
+
+		// Collect function call parts
+		List<AssistantMessage.ToolCall> assistantToolCalls = List.of();
+		if (candidate.content().isPresent() && candidate.content().get().parts().isPresent()) {
+			assistantToolCalls = candidate.content().get().parts().get().stream()
 				.filter(part -> part.functionCall().isPresent())
 				.map(part -> {
 					FunctionCall functionCall = part.functionCall().get();
@@ -663,45 +667,26 @@ protected List<Generation> responseCandidateToGeneration(Candidate candidate) {
 					return new AssistantMessage.ToolCall("", "function", functionName, functionArguments);
 				})
 				.toList();
+		}
 
+		// Handle the case where all parts are server-side tool invocations (no text, no function calls)
+		if (textContent.isEmpty() && assistantToolCalls.isEmpty()) {
 			AssistantMessage assistantMessage = AssistantMessage.builder()
 				.content("")
 				.properties(messageMetadata)
-				.toolCalls(assistantToolCalls)
 				.build();
-
 			return List.of(new Generation(assistantMessage, chatGenerationMetadata));
 		}
-		else {
-			List<Generation> generations = candidate.content()
-				.get()
-				.parts()
-				.orElse(List.of())
-				.stream()
-				.filter(part -> part.toolCall().isEmpty() && part.toolResponse().isEmpty())
-				.map(part -> {
-					var partMessageMetadata = new HashMap<>(messageMetadata);
-					partMessageMetadata.put("isThought", part.thought().orElse(false));
-					return AssistantMessage.builder()
-						.content(part.text().orElse(""))
-						.properties(partMessageMetadata)
-						.build();
-				})
-				.map(assistantMessage -> new Generation(assistantMessage, chatGenerationMetadata))
-				.toList();
 
-			// If all parts were server-side tool invocations, return a single generation
-			// with empty text but with the server-side tool invocation metadata
-			if (generations.isEmpty()) {
-				AssistantMessage assistantMessage = AssistantMessage.builder()
-					.content("")
-					.properties(messageMetadata)
-					.build();
-				return List.of(new Generation(assistantMessage, chatGenerationMetadata));
-			}
+		// Build a SINGLE generation with BOTH text and tool calls (mixed modality)
+		AssistantMessage assistantMessage = AssistantMessage.builder()
+			.content(textContent)
+			.properties(messageMetadata)
+			.toolCalls(assistantToolCalls.isEmpty() ? null : assistantToolCalls)
+			.build();
 
-			return generations;
-		}
+
+		return List.of(new Generation(assistantMessage, chatGenerationMetadata));
 	}
 
 	private ChatResponseMetadata toChatResponseMetadata(Usage usage, String modelVersion) {

models/spring-ai-google-genai/src/test/java/org/springframework/ai/google/genai/GoogleGenAiChatModelMixedContentTests.java

@@ -0,0 +1,139 @@
+/*
+ * Copyright 2023-present the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.ai.google.genai;
+
+import java.lang.reflect.Method;
+import java.util.List;
+import java.util.Map;
+
+import com.google.genai.types.Candidate;
+import com.google.genai.types.Content;
+import com.google.genai.types.FunctionCall;
+import com.google.genai.types.Part;
+import org.junit.jupiter.api.Test;
+
+import org.springframework.ai.chat.model.Generation;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+/**
+ * Regression tests for mixed-modality Gemini responses (text + functionCall parts). These
+ * tests verify that the fix for issue #5466 correctly handles mixed content.
+ *
+ * @author ENG
+ * @since 1.1.0
+ * @see <a href="https://github.com/spring-projects/spring-ai/issues/5466">Issue #5466</a>
+ */
+public class GoogleGenAiChatModelMixedContentTests {
+
+	@Test
+	@SuppressWarnings("unchecked")
+	void testMixedTextAndFunctionCallParts() throws Exception {
+		// Arrange: a candidate with both a TextPart and a FunctionCallPart
+		Part textPart = Part.builder().text("The answer is 42.").build();
+		Part functionCallPart = Part.builder()
+			.functionCall(FunctionCall.builder().name("get_weather").args(Map.of("location", "Toronto")).build())
+			.build();
+
+		Content content = Content.builder().parts(List.of(textPart, functionCallPart)).build();
+
+		Candidate candidate = Candidate.builder().content(content).index(0).build();
+
+		// Act: call responseCandidateToGeneration via reflection
+		GoogleGenAiChatModel model = GoogleGenAiChatModel.builder()
+			.defaultOptions(GoogleGenAiChatOptions.builder().build())
+			.build();
+		Method method = GoogleGenAiChatModel.class.getDeclaredMethod("responseCandidateToGeneration", Candidate.class);
+		method.setAccessible(true);
+		List<Generation> generations = (List<Generation>) method.invoke(model, candidate);
+
+		// Assert: exactly one generation with both text content and toolCalls
+		assertThat(generations).hasSize(1);
+		Generation generation = generations.get(0);
+		var assistantMessage = (org.springframework.ai.chat.messages.AssistantMessage) generation.getOutput();
+
+		// Text content must be preserved
+		assertThat(assistantMessage.getText()).isEqualTo("The answer is 42.");
+
+		// Tool calls must also be preserved (not dropped by allMatch logic)
+		assertThat(assistantMessage.getToolCalls()).isNotNull();
+		assertThat(assistantMessage.getToolCalls()).hasSize(1);
+		assertThat(assistantMessage.getToolCalls().get(0).name()).isEqualTo("get_weather");
+		assertThat(assistantMessage.getToolCalls().get(0).arguments()).contains("Toronto");
+	}
+
+	@Test
+	@SuppressWarnings("unchecked")
+	void testFunctionCallOnlyParts() throws Exception {
+		// Arrange: a candidate with only functionCall parts
+		Part functionCallPart1 = Part.builder()
+			.functionCall(FunctionCall.builder().name("get_weather").args(Map.of("location", "Toronto")).build())
+			.build();
+		Part functionCallPart2 = Part.builder()
+			.functionCall(FunctionCall.builder().name("get_time").args(Map.of("timezone", "America/Toronto")).build())
+			.build();
+
+		Content content = Content.builder().parts(List.of(functionCallPart1, functionCallPart2)).build();
+
+		Candidate candidate = Candidate.builder().content(content).index(0).build();
+
+		// Act
+		GoogleGenAiChatModel model = GoogleGenAiChatModel.builder()
+			.defaultOptions(GoogleGenAiChatOptions.builder().build())
+			.build();
+		Method method = GoogleGenAiChatModel.class.getDeclaredMethod("responseCandidateToGeneration", Candidate.class);
+		method.setAccessible(true);
+		List<Generation> generations = (List<Generation>) method.invoke(model, candidate);
+
+		// Assert: one generation with both tool calls and empty text content
+		assertThat(generations).hasSize(1);
+		var assistantMessage = (org.springframework.ai.chat.messages.AssistantMessage) generations.get(0).getOutput();
+
+		assertThat(assistantMessage.getText()).isEmpty();
+		assertThat(assistantMessage.getToolCalls()).hasSize(2);
+		assertThat(assistantMessage.getToolCalls().get(0).name()).isEqualTo("get_weather");
+		assertThat(assistantMessage.getToolCalls().get(1).name()).isEqualTo("get_time");
+	}
+
+	@Test
+	@SuppressWarnings("unchecked")
+	void testTextOnlyParts() throws Exception {
+		// Arrange: a candidate with only text parts
+		Part textPart1 = Part.builder().text("Hello ").build();
+		Part textPart2 = Part.builder().text("world!").build();
+
+		Content content = Content.builder().parts(List.of(textPart1, textPart2)).build();
+
+		Candidate candidate = Candidate.builder().content(content).index(0).build();
+
+		// Act
+		GoogleGenAiChatModel model = GoogleGenAiChatModel.builder()
+			.defaultOptions(GoogleGenAiChatOptions.builder().build())
+			.build();
+		Method method = GoogleGenAiChatModel.class.getDeclaredMethod("responseCandidateToGeneration", Candidate.class);
+		method.setAccessible(true);
+		List<Generation> generations = (List<Generation>) method.invoke(model, candidate);
+
+		// Assert: one generation with concatenated text and no tool calls
+		assertThat(generations).hasSize(1);
+		var assistantMessage = (org.springframework.ai.chat.messages.AssistantMessage) generations.get(0).getOutput();
+
+		assertThat(assistantMessage.getText()).isEqualTo("Hello world!");
+		assertThat(assistantMessage.getToolCalls()).isNullOrEmpty();
+	}
+
+}

spring-ai-rag/src/main/java/org/springframework/ai/rag/preretrieval/query/transformation/CompressionQueryTransformer.java

@@ -77,6 +77,12 @@ public CompressionQueryTransformer(ChatClient.Builder chatClientBuilder, @Nullab
 	public Query transform(Query query) {
 		Assert.notNull(query, "query cannot be null");
 
+
+		if (query.history().isEmpty()) {
+			logger.debug("Conversation history is empty. Returning the query unchanged.");
+			return query;
+		}
+
 		logger.debug("Compressing conversation history and follow-up query into a standalone query");
 
 		var compressedQueryText = this.chatClient.prompt()

spring-ai-rag/src/test/java/org/springframework/ai/rag/preretrieval/query/transformation/CompressionQueryTransformerTests.java

@@ -20,9 +20,11 @@
 
 import org.springframework.ai.chat.client.ChatClient;
 import org.springframework.ai.chat.prompt.PromptTemplate;
+import org.springframework.ai.rag.Query;
 
 import static org.assertj.core.api.Assertions.assertThatThrownBy;
 import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
 
 /**
  * Unit tests for {@link CompressionQueryTransformer}.
@@ -69,4 +71,18 @@ void whenPromptHasMissingQueryPlaceholderThenThrow() {
 			.hasMessageContaining("query");
 	}
 
+
+	@Test
+	void whenHistoryIsEmptyThenReturnQueryUnchanged() {
+		ChatClient.Builder chatClientBuilder = mock(ChatClient.Builder.class);
+		ChatClient chatClient = mock(ChatClient.class);
+		when(chatClientBuilder.build()).thenReturn(chatClient);
+		QueryTransformer queryTransformer = CompressionQueryTransformer.builder()
+			.chatClientBuilder(chatClientBuilder)
+			.build();
+		Query query = new Query("What is Spring AI?");
+		Query result = queryTransformer.transform(query);
+		org.assertj.core.api.Assertions.assertThat(result.text()).isEqualTo("What is Spring AI?");
+	}
+
 }