fix: Rethrow ToolExecutionException for non-RuntimeException (#3915)

Fixes #3915

Auto-cherry-pick to 1.0.x

- If the cause is a non-RuntimeException (e.g., IOException, OutOfMemoryError), rethrow the tool exception.
- Update the relevant description in docs

Signed-off-by: YunKui Lu <[email protected]>

Author: YunKuiLu

spring-ai-docs/src/main/antora/modules/ROOT/pages/api/tools.adoc

@@ -1197,7 +1197,7 @@ public interface ToolExecutionExceptionProcessor {
 }
 ----
 
-If you're using any of the Spring AI Spring Boot Starters, `DefaultToolExecutionExceptionProcessor` is the autoconfigured implementation of the `ToolExecutionExceptionProcessor` interface. By default, the error message is sent back to the model. The `DefaultToolExecutionExceptionProcessor` constructor lets you set the `alwaysThrow` attribute to `true` or `false`. If `true`, an exception will be thrown instead of sending an error message back to the model.
+If you're using any of the Spring AI Spring Boot Starters, `DefaultToolExecutionExceptionProcessor` is the autoconfigured implementation of the `ToolExecutionExceptionProcessor` interface. By default, the error message of `RuntimeException` is sent back to the model, while checked exceptions and Errors (e.g., `IOException`, `OutOfMemoryError`) are always thrown. The `DefaultToolExecutionExceptionProcessor` constructor lets you set the `alwaysThrow` attribute to `true` or `false`. If `true`, an exception will be thrown instead of sending an error message back to the model.
 
 You can use the ``spring.ai.tools.throw-exception-on-error` property to control the behavior of the `DefaultToolExecutionExceptionProcessor` bean:
 

spring-ai-model/src/main/java/org/springframework/ai/tool/execution/DefaultToolExecutionExceptionProcessor.java

@@ -18,6 +18,7 @@
 
 import java.util.Collections;
 import java.util.List;
+
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -30,11 +31,12 @@
  *
  * @author Thomas Vitale
  * @author Daniel Garnier-Moiroux
+ * @author YunKui Lu
  * @since 1.0.0
  */
 public class DefaultToolExecutionExceptionProcessor implements ToolExecutionExceptionProcessor {
 
-	private final static Logger logger = LoggerFactory.getLogger(DefaultToolExecutionExceptionProcessor.class);
+	private static final Logger logger = LoggerFactory.getLogger(DefaultToolExecutionExceptionProcessor.class);
 
 	private static final boolean DEFAULT_ALWAYS_THROW = false;
 
@@ -56,10 +58,17 @@ public DefaultToolExecutionExceptionProcessor(boolean alwaysThrow,
 	public String process(ToolExecutionException exception) {
 		Assert.notNull(exception, "exception cannot be null");
 		Throwable cause = exception.getCause();
-		if (cause instanceof RuntimeException runtimeException
-				&& this.rethrownExceptions.stream().anyMatch(rethrown -> rethrown.isAssignableFrom(cause.getClass()))) {
-			throw runtimeException;
+		if (cause instanceof RuntimeException runtimeException) {
+			if (this.rethrownExceptions.stream().anyMatch(rethrown -> rethrown.isAssignableFrom(cause.getClass()))) {
+				throw runtimeException;
+			}
+		}
+		else {
+			// If the cause is not a RuntimeException (e.g., IOException,
+			// OutOfMemoryError), rethrow the tool exception.
+			throw exception;
 		}
+
 		if (this.alwaysThrow) {
 			throw exception;
 		}

spring-ai-model/src/test/java/org/springframework/ai/tool/execution/DefaultToolExecutionExceptionProcessorTests.java

@@ -17,9 +17,11 @@
 package org.springframework.ai.tool.execution;
 
 import java.util.List;
+
 import org.junit.jupiter.api.Test;
 
 import org.springframework.ai.tool.definition.DefaultToolDefinition;
+
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.assertj.core.api.Assertions.assertThatThrownBy;
 import static org.assertj.core.api.InstanceOfAssertFactories.type;
@@ -33,12 +35,21 @@ class DefaultToolExecutionExceptionProcessorTests {
 
 	private final IllegalStateException toolException = new IllegalStateException("Inner exception");
 
+	private final Exception toolCheckedException = new Exception("Checked exception");
+
+	private final Error toolError = new Error("Error");
+
 	private final DefaultToolDefinition toolDefinition = new DefaultToolDefinition("toolName", "toolDescription",
 			"inputSchema");
 
 	private final ToolExecutionException toolExecutionException = new ToolExecutionException(toolDefinition,
 			toolException);
 
+	private final ToolExecutionException toolExecutionCheckedException = new ToolExecutionException(toolDefinition,
+			toolCheckedException);
+
+	private final ToolExecutionException toolExecutionError = new ToolExecutionException(toolDefinition, toolError);
+
 	@Test
 	void processReturnsMessage() {
 		DefaultToolExecutionExceptionProcessor processor = DefaultToolExecutionExceptionProcessor.builder().build();
@@ -96,4 +107,27 @@ void processRethrowsOnlySelectExceptions() {
 		assertThat(result).isEqualTo("This exception was not rethrown");
 	}
 
+	@Test
+	void processThrowsCheckedException() {
+		DefaultToolExecutionExceptionProcessor processor = DefaultToolExecutionExceptionProcessor.builder().build();
+
+		assertThatThrownBy(() -> processor.process(this.toolExecutionCheckedException))
+			.hasMessage(this.toolCheckedException.getMessage())
+			.hasCauseInstanceOf(this.toolCheckedException.getClass())
+			.asInstanceOf(type(ToolExecutionException.class))
+			.extracting(ToolExecutionException::getToolDefinition)
+			.isEqualTo(this.toolDefinition);
+	}
+
+	@Test
+	void processThrowsError() {
+		DefaultToolExecutionExceptionProcessor processor = DefaultToolExecutionExceptionProcessor.builder().build();
+
+		assertThatThrownBy(() -> processor.process(this.toolExecutionError)).hasMessage(this.toolError.getMessage())
+			.hasCauseInstanceOf(this.toolError.getClass())
+			.asInstanceOf(type(ToolExecutionException.class))
+			.extracting(ToolExecutionException::getToolDefinition)
+			.isEqualTo(this.toolDefinition);
+	}
+
 }