Conversation
Do one iteration to catch exceptions occurred beforehand to return an error instead of sending headers for SSE. Error handling during the execution is not defined in the spec: a2aproject/A2A#1262.
Summary of ChangesHello, 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 enhances the robustness of REST API streaming endpoints by addressing a critical error handling flaw. Previously, errors occurring early in a streaming request could lead to a broken client connection rather than a structured error response. The changes ensure that such errors are now properly intercepted and returned as standard JSON error messages, significantly improving the client experience and API reliability for streaming operations. Highlights
Using Gemini Code AssistThe full guide for Gemini Code Assist can be found on our documentation page, here are some quick tips. Invoking Gemini You can request assistance from Gemini at any point by creating a comment using either
Customization To customize Gemini Code Assist for GitHub experience, repository maintainers can create a configuration file and/or provide a custom code review style guide (such as PEP-8 for Python) by creating and adding files to a Limitations & Feedback Gemini Code Assist may make mistakes. Please leave feedback on any instances where its feedback is incorrect or counter productive. You can react with 👍 and 👎 on @gemini-code-assist comments. If you're interested in giving your feedback about your experience with Gemini Code Assist for GitHub and other Google products, sign up here. Footnotes
|
![gemini-code-assist[bot]](https://avatars.githubusercontent.com/in/956858?s=60&v=4){kind=small}
There was a problem hiding this comment.
Code Review
This pull request effectively addresses a key issue in REST streaming error handling by eagerly fetching the first event. This ensures that exceptions occurring before the stream begins are properly caught and returned as JSON errors instead of breaking the SSE connection. The implementation is clean and the addition of the test_client_handles_a2a_errors_streaming integration test provides excellent coverage for this new behavior. I've added one suggestion to further improve the robustness of the error handling for the first event.
🧪 Code Coverage (vs
|
| Base | PR | Delta | |
|---|---|---|---|
| src/a2a/server/apps/rest/rest_adapter.py | 82.28% | 83.53% | 🟢 +1.25% |
| Total | 91.38% | 91.39% | 🟢 +0.01% |
Generated by coverage-comment.yml
🤖 I have created a release *beep* *boop* --- ## [1.0.0-alpha.1](v1.0.0-alpha.0...v1.0.0-alpha.1) (2026-04-10) ### ⚠ BREAKING CHANGES * **client:** make ClientConfig.push_notification_config singular ([#955](#955)) * **client:** reorganize ClientFactory API ([#947](#947)) * **server:** add build_user function to DefaultContextBuilder to allow A2A user creation customization ([#925](#925)) * **client:** remove `ClientTaskManager` and `Consumers` from client ([#916](#916)) * **server:** migrate from Application wrappers to Starlette route-based endpoints for rest ([#892](#892)) * **server:** migrate from Application wrappers to Starlette route-based endpoints for jsonrpc ([#873](#873)) ### Features * A2A Version Header validation on server side. ([#865](#865)) ([b261ceb](b261ceb)) * Add GetExtendedAgentCard Support to RequestHandlers ([#919](#919)) ([2159140](2159140)) * Add support for more Task Message and Artifact fields in the Vertex Task Store ([#936](#936)) ([605fa49](605fa49)) * Create EventQueue interface and make tap() async. ([#914](#914)) ([9ccf99c](9ccf99c)), closes [#869](#869) * EventQueue - unify implementation between python versions ([#877](#877)) ([7437b88](7437b88)), closes [#869](#869) * EventQueue is now a simple interface with single enqueue_event method. ([#944](#944)) ([f0e1d74](f0e1d74)) * Implementation of DefaultRequestHandlerV2 ([#933](#933)) ([462eb3c](462eb3c)), closes [#869](#869) * InMemoryTaskStore creates a copy of Task by default to make it consistent with database task stores ([#887](#887)) ([8c65e84](8c65e84)), closes [#869](#869) * merge metadata of new and old artifact when append=True ([#945](#945)) ([cc094aa](cc094aa)) * **server:** add async context manager support to EventQueue ([#743](#743)) ([f68b22f](f68b22f)) * **server:** validate presence according to `google.api.field_behavior` annotations ([#870](#870)) ([4586c3e](4586c3e)) * Simplify ActiveTask.subscribe() ([#958](#958)) ([62e5e59](62e5e59)) * Support AgentExectuor enqueue of a Task object. ([#960](#960)) ([12ce017](12ce017)) * Support Message-only simplified execution without creating Task ([#956](#956)) ([354fdfb](354fdfb)) * Unhandled exception in AgentExecutor marks task as failed ([#943](#943)) ([4fc6b54](4fc6b54)) ### Bug Fixes * Add `packaging` to base dependencies ([#897](#897)) ([7a9aec7](7a9aec7)) * **client:** do not mutate SendMessageRequest in BaseClient.send_message ([#949](#949)) ([94537c3](94537c3)) * fix `athrow()` RuntimeError on streaming responses ([#912](#912)) ([ca7edc3](ca7edc3)) * fix docstrings related to `CallContextBuilder` args in constructors and make ServerCallContext mandatory in `compat` folder ([#907](#907)) ([9cade9b](9cade9b)) * fix error handling for gRPC and SSE streaming ([#879](#879)) ([2b323d0](2b323d0)) * fix JSONRPC error handling ([#957](#957)) ([6c807d5](6c807d5)) * fix REST error handling ([#893](#893)) ([405be3f](405be3f)) * handle SSE errors occurred after stream started ([#894](#894)) ([3a68d8f](3a68d8f)) * remove the use of deprecated types from VertexTaskStore ([#889](#889)) ([6d49122](6d49122)) * Remove unconditional SQLAlchemy dependency from SDK core ([#898](#898)) ([ab762f0](ab762f0)), closes [#883](#883) * remove unused import and request for FastAPI in pyproject ([#934](#934)) ([fe5de77](fe5de77)) * replace stale entry in a2a.types.__all__ with actual import name ([#902](#902)) ([05cd5e9](05cd5e9)) * wrong method name for ExtendedAgentCard endpoint in JsonRpc compat version ([#931](#931)) ([5d22186](5d22186)) ### Documentation * add Database Migration Documentation ([#864](#864)) ([fd12dff](fd12dff)) ### Miscellaneous Chores * release 1.0.0-alpha.1 ([a61f6d4](a61f6d4)) ### Code Refactoring * **client:** make ClientConfig.push_notification_config singular ([#955](#955)) ([be4c5ff](be4c5ff)) * **client:** remove `ClientTaskManager` and `Consumers` from client ([#916](#916)) ([97058bb](97058bb)), closes [#734](#734) * **client:** reorganize ClientFactory API ([#947](#947)) ([01b3b2c](01b3b2c)) * **server:** add build_user function to DefaultContextBuilder to allow A2A user creation customization ([#925](#925)) ([2648c5e](2648c5e)) * **server:** migrate from Application wrappers to Starlette route-based endpoints for jsonrpc ([#873](#873)) ([734d062](734d062)) * **server:** migrate from Application wrappers to Starlette route-based endpoints for rest ([#892](#892)) ([4be2064](4be2064)) --- This PR was generated with [Release Please](https://github.com/googleapis/release-please). See [documentation](https://github.com/googleapis/release-please#release-please).
2 participants
Do one iteration to catch exceptions occurred beforehand to return an error instead of sending headers for SSE. Error handling during the execution is not defined in the spec: a2aproject/A2A#1262.