chore: add Jspecify NullCheck in grpc transport (Fixes #334) #342

devcom33 · 2025-10-13T00:58:36Z

This PR adds Jspecify nullness annotations to the gRPC transport module:

Added @NullMarked in package-info.java for the package.
Annotated nullable parameters with @nullable in GrpcTransport.java and related classes.
Ensured all fields and method signatures match nullability expectations.
Fixed NullAway errors by initializing non-null fields and updating constructor annotations.
All tests pass successfully.

gemini-code-assist · 2025-10-13T00:58:49Z

Summary of Changes

Hello @devcom33, 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 significantly improves the null-safety of the gRPC transport client by introducing Jspecify nullness annotations. The primary goal is to make the codebase more robust and maintainable by allowing static analysis tools to catch potential null-related issues at compile time, thereby reducing runtime NullPointerExceptions and clarifying the nullability contracts of the API.

Highlights

Jspecify Nullness Annotations: Integrated Jspecify nullness annotations across the gRPC transport module to enhance null-safety and prevent NullPointerExceptions.
Package-level NullMarked: The io.a2a.client.transport.grpc package is now marked with @NullMarked in its package-info.java, indicating that all types within the package are non-null by default unless explicitly annotated as @Nullable.
Nullable Parameter Annotations: Numerous parameters in GrpcTransport.java and PayloadAndHeaders.java that can legitimately be null have been explicitly annotated with @Nullable.
NullAway Error Fixes: Addressed and fixed NullAway errors by ensuring non-null fields are properly initialized, such as the channelFactory in GrpcTransportConfigBuilder, and by updating constructor annotations to reflect nullability expectations.

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gemini-code-assist

Code Review

This pull request effectively adds JSpecify nullness annotations across the gRPC transport module, improving code safety and clarity. The use of @NullMarked at the package level is a great step towards ensuring null-safety. My main feedback is a suggestion to improve the builder pattern in GrpcTransportConfigBuilder to fail-fast instead of fail-late, which will make it more robust. Overall, this is a solid improvement.

gemini-code-assist · 2025-10-13T01:00:20Z

...nt/transport/grpc/src/main/java/io/a2a/client/transport/grpc/GrpcTransportConfigBuilder.java

 public class GrpcTransportConfigBuilder extends ClientTransportConfigBuilder<GrpcTransportConfig, GrpcTransportConfigBuilder> {

-    private Function<String, Channel> channelFactory;
+    private Function<String, Channel> channelFactory = s -> { throw new IllegalStateException("channelFactory not set"); };


While this initialization fixes the NullAway warning for a non-nullable field, it creates a 'fail-late' scenario where an exception is only thrown when the channelFactory is eventually used. A better practice for builders is to 'fail-fast' by validating the state in the build() method.

I recommend marking channelFactory as @Nullable and then adding a check in the build() method to ensure it has been set before creating the GrpcTransportConfig object. This prevents the creation of a partially initialized, unusable configuration object.

You'll also need to add import org.jspecify.annotations.Nullable;.

For example, you could change the build() method to something like this:

@Override public GrpcTransportConfig build() { if (channelFactory == null) { throw new IllegalStateException("channelFactory must be set"); } GrpcTransportConfig config = new GrpcTransportConfig(channelFactory); config.setInterceptors(interceptors); return config; }

Suggested change

private Function<String, Channel> channelFactory = s -> { throw new IllegalStateException("channelFactory not set"); };

private @Nullable Function<String, Channel> channelFactory;

ehsavoie · 2025-10-13T07:49:24Z

@devcom33 may you fix gemini comments please ?

…ject#334)

devcom33 · 2025-10-13T11:52:55Z

Hey @ehsavoie , I’ve updated the builder to use the fail-fast pattern as suggested.
Thanks for your feedback.

gemini-code-assist

Code Review

This pull request effectively introduces JSpecify nullness annotations to the gRPC transport module, which is a great step towards improving code safety and clarity. The changes are mostly correct and follow the PR's intent. I've pointed out a couple of minor issues: one regarding Javadoc completeness for a method with newly nullable parameters, and another about using a consistent @Nullable annotation across all modified files. Addressing these will make the changes even better.

client/transport/grpc/src/main/java/io/a2a/client/transport/grpc/GrpcTransport.java

gemini-code-assist · 2025-10-14T10:54:37Z

...nt/transport/grpc/src/main/java/io/a2a/client/transport/grpc/GrpcTransportConfigBuilder.java

 import io.a2a.client.transport.spi.ClientTransportConfigBuilder;
 import io.a2a.util.Assert;
 import io.grpc.Channel;
+import jakarta.annotation.Nullable;


This pull request's goal is to add JSpecify nullness annotations. For consistency with other changes in this PR, please use org.jspecify.annotations.Nullable instead of jakarta.annotation.Nullable.

Suggested change

import jakarta.annotation.Nullable;

import org.jspecify.annotations.Nullable;

devcom33

/gemini review

…le params

gemini-code-assist

Code Review

This pull request effectively introduces JSpecify nullness annotations to the gRPC transport module, enhancing code safety and clarity. The changes are consistent across the modified files, with @Nullable annotations correctly applied to parameters and fields that can be null. The added validation in GrpcTransportConfigBuilder is a good defensive measure. I have one suggestion in GrpcTransport.java to remove an unused parameter, which will further improve code quality.

client/transport/grpc/src/main/java/io/a2a/client/transport/grpc/GrpcTransport.java

devcom33 · 2025-10-14T12:47:28Z

/gemini review

gemini-code-assist

Code Review

This pull request does a great job of introducing JSpecify nullness annotations to the gRPC transport module. The use of @NullMarked at the package level and @Nullable on parameters and fields significantly improves the code's null-safety and makes contracts clearer. The refactoring to remove unused parameters and the added validation in GrpcTransportConfigBuilder are also excellent improvements. I have one minor suggestion to enhance the robustness of the GrpcTransport constructor.

gemini-code-assist · 2025-10-14T12:49:08Z

client/transport/grpc/src/main/java/io/a2a/client/transport/grpc/GrpcTransport.java

    }

-    public GrpcTransport(Channel channel, AgentCard agentCard, List<ClientCallInterceptor> interceptors) {
+    public GrpcTransport(Channel channel, AgentCard agentCard, @Nullable List<ClientCallInterceptor> interceptors) {


For improved robustness and to align with the non-null contract of the agentCard field (as per @NullMarked on the package), it's good practice to validate the agentCard parameter for nullity in this public constructor. This ensures that the GrpcTransport is always instantiated in a valid state.

Consider adding checkNotNullParam("agentCard", agentCard); at the start of the constructor body.

devcom33 · 2025-10-14T13:09:07Z

/gemini review

gemini-code-assist

Code Review

This pull request effectively introduces JSpecify nullness annotations to the gRPC transport module, significantly improving code safety and clarity. The addition of @NullMarked at the package level establishes a solid foundation for null-safety. Key changes include correctly annotating nullable parameters, especially ClientCallContext, across the GrpcTransport class. The introduction of runtime null checks in GrpcTransport's constructor for agentCard and in GrpcTransportConfigBuilder for channelFactory are excellent additions that prevent potential NullPointerExceptions and fix issues likely flagged by NullAway. The refactoring to remove an unused parameter from createGrpcSendMessageRequest is a nice cleanup. Overall, this is a high-quality contribution that enhances the robustness of the codebase.

fjuma · 2025-10-14T19:27:14Z

client/transport/grpc/src/main/java/io/a2a/client/transport/grpc/GrpcTransport.java

        checkNotNullParam("request", request);

-        SendMessageRequest sendMessageRequest = createGrpcSendMessageRequest(request, context);
+        SendMessageRequest sendMessageRequest = createGrpcSendMessageRequest(request);


context should be added back here.

fjuma · 2025-10-14T19:27:29Z

client/transport/grpc/src/main/java/io/a2a/client/transport/grpc/GrpcTransport.java

        checkNotNullParam("request", request);
        checkNotNullParam("eventConsumer", eventConsumer);
-        SendMessageRequest grpcRequest = createGrpcSendMessageRequest(request, context);
+        SendMessageRequest grpcRequest = createGrpcSendMessageRequest(request);


Same here, context should be added back.

fjuma · 2025-10-14T19:28:15Z

client/transport/grpc/src/main/java/io/a2a/client/transport/grpc/GrpcTransport.java

    }

-    private SendMessageRequest createGrpcSendMessageRequest(MessageSendParams messageSendParams, ClientCallContext context) {
+    private SendMessageRequest createGrpcSendMessageRequest(MessageSendParams messageSendParams) {


We shouldn't remove context here.

...nt/transport/grpc/src/main/java/io/a2a/client/transport/grpc/GrpcTransportConfigBuilder.java

devcom33 · 2025-10-14T21:35:38Z

thank you @fjuma for your feedbacks
i've restored the context parameter in createGrpcSendMessageRequest method as you suggested.
Additionally, i removed the @nullable annotation from channelFactory.

please let me know if there's anything else you need or if further changes are required.

...nt/transport/grpc/src/main/java/io/a2a/client/transport/grpc/GrpcTransportConfigBuilder.java

fjuma · 2025-10-17T16:09:56Z

Thanks @devcom33!

devcom33 · 2025-10-17T16:17:57Z

thank you for merging the PR.
would it be possible to add the hacktoberfest-accepted label to the PR? I'd really appreciate it!

fjuma · 2025-10-17T16:22:44Z

@devcom33 Sure thing, I've added the label.

a2aproject#342) This PR adds Jspecify nullness annotations to the gRPC transport module: - Added @NullMarked in package-info.java for the package. - Annotated nullable parameters with @nullable in GrpcTransport.java and related classes. - Ensured all fields and method signatures match nullability expectations. - Fixed NullAway errors by initializing non-null fields and updating constructor annotations. - All tests pass successfully. --------- Co-authored-by: devcom33 <devcom33@users.noreply.github.com>

Add Jspecify NullCheck in the grpc transport. Fixes a2aproject#334

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devcom33 changed the title ~~Add Jspecify NullCheck in the grpc transport. Fixes #334~~ fix: add Jspecify NullCheck in grpc transport (Fixes #334) Oct 13, 2025

fix: apply fail-fast builder pattern for channelFactory (Fixes a2apro…

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…ject#334)

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devcom33 commented Oct 14, 2025

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fix: use org.jspecify.annotations.Nullable and add Javadoc for nullab…

e290d63

…le params

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client/transport/grpc/src/main/java/io/a2a/client/transport/grpc/GrpcTransport.java Show resolved Hide resolved

fix: remove unused context parameter from createGrpcSendMessageRequest

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devcom33 changed the title ~~fix: add Jspecify NullCheck in grpc transport (Fixes #334)~~ chore: add Jspecify NullCheck in grpc transport (Fixes #334) Oct 14, 2025

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fix: validate agentCard parameter in GrpcTransport constructor

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...nt/transport/grpc/src/main/java/io/a2a/client/transport/grpc/GrpcTransportConfigBuilder.java Show resolved Hide resolved

fjuma requested a review from ehsavoie October 14, 2025 19:31

fix: revert context parameter removal and channelFactory nullability

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ehsavoie mentioned this pull request Oct 15, 2025

[chore]: Add Jspecify NullCheck in the grpc transport #334

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...nt/transport/grpc/src/main/java/io/a2a/client/transport/grpc/GrpcTransportConfigBuilder.java Outdated Show resolved Hide resolved

fix: add explicit null check for channelFactory in build method

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devcom33 requested a review from fjuma October 17, 2025 15:57

ehsavoie approved these changes Oct 17, 2025

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fjuma added the hacktoberfest-accepted label Oct 17, 2025

fjuma merged commit 8e83576 into a2aproject:main Oct 17, 2025
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	private Function<String, Channel> channelFactory = s -> { throw new IllegalStateException("channelFactory not set"); };
	private @Nullable Function<String, Channel> channelFactory;

	import jakarta.annotation.Nullable;
	import org.jspecify.annotations.Nullable;

chore: add Jspecify NullCheck in grpc transport (Fixes #334) #342

chore: add Jspecify NullCheck in grpc transport (Fixes #334) #342

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