fix(tool): preserve generic type info in ToolMethodInvoker

[LearningGp]

AgentScope-Java Version

1.0.9

Description

ref(#677)

run test

Checklist

Please check the following items before code is ready to be reviewed.

• Code has been formatted with mvn spotless:apply
• All tests are passing (mvn test)
• Javadoc comments are complete and follow project conventions
• Related documentation has been updated (e.g. links, examples, etc.)
• Code is ready for review

[gemini-code-assist]

Summary of Changes

Hello @LearningGp, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request addresses a critical issue where generic type information was not correctly preserved during the deserialization of tool parameters, leading to runtime errors. By enhancing the JSON codec to leverage java.lang.reflect.Type for conversions, the system can now accurately handle complex generic structures, significantly improving the robustness and flexibility of tool parameter processing.

Highlights

• Generic Type Preservation: Modified the ToolMethodInvoker to correctly preserve generic type information (e.g., List<MyClass>, Map<String, MyClass>) when converting tool parameters. This resolves ClassCastException issues that occurred when complex generic types were deserialized from JSON.
• JSON Codec Enhancement: Extended the JsonCodec interface and its JacksonJsonCodec implementation with a new convertValue method that accepts java.lang.reflect.Type. This allows the JSON conversion process to utilize full type information, including generics.
• Comprehensive Unit Tests: Added extensive unit tests to ToolMethodInvokerTest to validate the correct handling of various generic types, including lists of custom objects, maps with custom object values, and nested generic lists, ensuring the fix works as expected.

Changelog

• agentscope-core/src/main/java/io/agentscope/core/tool/ToolMethodInvoker.java
  • Updated convertSingleParameter to use parameter.getParameterizedType() for JSON conversion, ensuring generic type information is passed to the codec.
  • Adjusted direct assignment logic to only apply when the target parameter is not a parameterized type, preventing premature type loss.
• agentscope-core/src/main/java/io/agentscope/core/util/JacksonJsonCodec.java
  • Added import com.fasterxml.jackson.databind.JavaType; and import java.lang.reflect.Type;.
  • Implemented a new convertValue(Object from, Type toType) method to handle conversions using java.lang.reflect.Type.
• agentscope-core/src/main/java/io/agentscope/core/util/JsonCodec.java
  • Added import java.lang.reflect.Type;.
  • Introduced a new convertValue(Object from, Type toType) method to the interface, along with Javadoc explaining its purpose for generic type preservation.
• agentscope-core/src/test/java/io/agentscope/core/tool/ToolMethodInvokerTest.java
  • Added imports for ArrayList, List, and Objects.
  • Introduced new test methods (listSizeMethod, processOrderItems, mapMethod, nestedListMethod) within TestTools to test generic type handling.
  • Created OrderItem static inner class for custom generic type testing.
  • Added several new @Test methods (testGenericList_WithCustomClass, testGenericList_SizeMethod, testGenericList_EmptyList, testGenericMap_WithCustomClassValue, testNestedGenericList) to thoroughly verify generic type deserialization.
• agentscope-core/src/test/java/io/agentscope/core/util/JsonUtilsTest.java
  • Added import java.lang.reflect.Type;.
  • Updated the mock JsonCodec implementation to include the new convertValue(Object from, Type toType) method.

Activity

• The author referenced issue ToolMethodInvoker loses generic type information for List<T> parameters #677, indicating this PR is a fix for a known problem.
• The author performed local testing, as indicated by 'run test'.
• The author completed all checklist items, including code formatting, passing tests, Javadoc, documentation updates, and marking the code ready for review.

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[gemini-code-assist]

Code Review

This pull request addresses an issue with generic type handling in the ToolMethodInvoker. The changes correctly preserve generic type information (e.g., for List<MyClass>) during parameter conversion by leveraging Parameter.getParameterizedType() and extending JsonCodec to handle java.lang.reflect.Type. The implementation in JacksonJsonCodec correctly uses Jackson's TypeFactory to construct the full generic type. The fix is well-supported by a comprehensive set of new unit tests that cover lists, maps, and nested generics. The overall change is excellent and significantly improves the robustness of tool invocation. I have one suggestion to improve an assertion in a test case to make it more robust.

[gemini-code-assist]

The current assertion only verifies the presence of product names, but not their association with the correct keys. This could potentially miss bugs where the mapping is incorrect. A more robust assertion should check for the key-value pairs.

Suggested change

	// The order of map entries is not guaranteed, so check for both possibilities
	Assertions.assertTrue(
	content.contains("ProductA") && content.contains("ProductB"),
	"Response should contain both product names");
	// The order of map entries is not guaranteed, so check that both key-value pairs are present.
	Assertions.assertTrue(
	content.contains("key1=ProductA") && content.contains("key2=ProductB"),
	"Response should contain both key-value pairs. Actual: " + content);

[Copilot]

Pull request overview

This pull request fixes Issue #677 where ToolMethodInvoker was losing generic type information when deserializing parameters with generic types like List<MyClass>. Previously, this resulted in ClassCastException when trying to iterate over the list items because Jackson would deserialize to LinkedHashMap instead of the actual type.

Changes:

• Added convertValue(Object, Type) method to JsonCodec interface to support generic type preservation
• Updated ToolMethodInvoker to use getParameterizedType() instead of getType() when converting parameters
• Added comprehensive test coverage for generic type handling including List, Map, and nested generic types

Reviewed changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
agentscope-core/src/main/java/io/agentscope/core/util/JsonCodec.java	Added new interface method to preserve generic type information during conversion
agentscope-core/src/main/java/io/agentscope/core/util/JacksonJsonCodec.java	Implemented the new method using Jackson's TypeFactory for proper generic handling
agentscope-core/src/main/java/io/agentscope/core/tool/ToolMethodInvoker.java	Updated parameter conversion logic to use parameterized types and the new conversion method
agentscope-core/src/test/java/io/agentscope/core/tool/ToolMethodInvokerTest.java	Added comprehensive tests for generic List, Map, nested generics, and edge cases
agentscope-core/src/test/java/io/agentscope/core/util/JsonUtilsTest.java	Updated mock implementation to include the new interface method

Comments suppressed due to low confidence (1)

agentscope-core/src/main/java/io/agentscope/core/util/JsonCodec.java:102

• Method JsonCodec.convertValue(..) could be confused with overloaded method convertValue, since dispatch depends on static types.

    <T> T convertValue(Object from, Class<T> toType);

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.

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