CAMEL-24538: camel-openai - fix operator precedence so an empty userMessage does not drop the body prompt

components/camel-ai/camel-openai/src/main/java/org/apache/camel/component/openai/OpenAIProducer.java

@@ -251,11 +251,11 @@ private List<ChatCompletionMessageParam> buildMessages(Exchange exchange, OpenAI
 
         String systemPrompt = in.getHeader(OpenAIConstants.SYSTEM_MESSAGE, String.class);
         String developerPrompt = in.getHeader(OpenAIConstants.DEVELOPER_MESSAGE, String.class);
-        if (systemPrompt == null || systemPrompt.isEmpty() && ObjectHelper.isNotEmpty(config.getSystemMessage())) {
+        if ((systemPrompt == null || systemPrompt.isEmpty()) && ObjectHelper.isNotEmpty(config.getSystemMessage())) {
             systemPrompt = config.getSystemMessage();
         }
-        if (developerPrompt == null
-                || developerPrompt.isEmpty() && ObjectHelper.isNotEmpty(config.getDeveloperMessage())) {
+        if ((developerPrompt == null || developerPrompt.isEmpty())
+                && ObjectHelper.isNotEmpty(config.getDeveloperMessage())) {
             developerPrompt = config.getDeveloperMessage();
         }
 
@@ -308,7 +308,7 @@ private void addConversationHistory(
     private ChatCompletionMessageParam buildUserMessage(Message in, OpenAIConfiguration config) throws Exception {
         Object body = in.getBody();
         String userPrompt = in.getHeader(OpenAIConstants.USER_MESSAGE, String.class);
-        if (userPrompt == null || userPrompt.isEmpty() && ObjectHelper.isNotEmpty(config.getUserMessage())) {
+        if ((userPrompt == null || userPrompt.isEmpty()) && ObjectHelper.isNotEmpty(config.getUserMessage())) {
             userPrompt = config.getUserMessage();
         }
 

components/camel-ai/camel-openai/src/test/java/org/apache/camel/component/openai/OpenAIEmptyUserMessageBodyPromptTest.java

@@ -0,0 +1,69 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You 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
+ *
+ *      http://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.apache.camel.component.openai;
+
+import org.apache.camel.Exchange;
+import org.apache.camel.builder.RouteBuilder;
+import org.apache.camel.test.infra.openai.mock.OpenAIMock;
+import org.apache.camel.test.junit6.CamelTestSupport;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.RegisterExtension;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+/**
+ * When the userMessage option is configured to an empty string, it must not shadow the prompt supplied in the message
+ * body. An operator-precedence bug used to set the (empty) configured message as the prompt, dropping the body and
+ * failing with "No input provided".
+ */
+public class OpenAIEmptyUserMessageBodyPromptTest extends CamelTestSupport {
+
+    @RegisterExtension
+    public OpenAIMock openAIMock = new OpenAIMock().builder()
+            .when("hello from body")
+            .replyWith("mock reply")
+            .end()
+            .build();
+
+    @Override
+    protected RouteBuilder createRouteBuilder() {
+        return new RouteBuilder() {
+            @Override
+            public void configure() {
+                from("direct:empty-user-message")
+                        .to("openai:chat-completion?model=gpt-4&apiKey=dummy&baseUrl="
+                            + openAIMock.getBaseUrl() + "/v1");
+            }
+        };
+    }
+
+    @Test
+    void bodyPromptIsUsedWhenConfiguredUserMessageIsEmpty() {
+        // Configure the route's endpoint with an empty userMessage - the exact case the precedence bug mishandled.
+        OpenAIEndpoint endpoint = context.getEndpoints().stream()
+                .filter(OpenAIEndpoint.class::isInstance)
+                .map(OpenAIEndpoint.class::cast)
+                .findFirst()
+                .orElseThrow(() -> new IllegalStateException("no OpenAIEndpoint found"));
+        endpoint.getConfiguration().setUserMessage("");
+
+        Exchange result = template.request("direct:empty-user-message", e -> e.getIn().setBody("hello from body"));
+
+        assertThat(result.getException()).isNull();
+        assertThat(result.getMessage().getBody(String.class)).contains("mock reply");
+    }
+}