feat: A2A Version Header validation on server side.

[bartek-w]

No description provided.

[gemini-code-assist]

Summary of Changes

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This pull request represents a major architectural upgrade for the A2A Python SDK, focusing on full adoption of A2A Protocol v1.0. It introduces direct Protobuf usage for improved type safety and performance, alongside a robust backward compatibility layer for v0.3. Key enhancements include a standardized error handling mechanism, integration of Alembic for database migrations, and a flexible client-side interceptor pattern. These changes modernize the SDK's foundation, ensuring future extensibility and interoperability while maintaining support for existing deployments.

Highlights

• A2A Protocol v1.0 Adoption: The SDK has undergone a significant refactoring to align with A2A Protocol v1.0, transitioning from Pydantic models to direct usage of Protobuf types for core data structures across client and server components.
• Backward Compatibility for v0.3: A comprehensive compatibility layer has been introduced under src/a2a/compat/v0_3 to enable seamless interaction between v1.0 clients/servers and legacy v0.3 systems. This includes dedicated adapters and conversion utilities for gRPC, JSON-RPC, and REST transports.
• Enhanced Error Handling: The client and server error hierarchies have been refactored to introduce specific A2AError types, which are now consistently mapped to standard HTTP, gRPC, and JSON-RPC error codes for more robust and predictable error management.
• Database Migration Integration: Alembic has been integrated to manage database schema changes, including a new CLI tool (a2a-db) and initial migration scripts. This adds owner, last_updated, and protocol_version columns to task and push notification configuration tables, ensuring proper data versioning and ownership tracking.
• Client Interceptor Pattern: The client architecture now supports an interceptor pattern (ClientCallInterceptor) allowing for flexible modification of requests and responses, which is crucial for features like authentication and custom headers.
• Updated Code Generation Workflow: The protobuf code generation process has been updated with new buf.gen.yaml configurations and shell scripts (gen_proto.sh, gen_proto_compat.sh) to support the new v1.0 structure and generate compatibility layers for v0.3.

Ignored Files

• Ignored by pattern: .github/workflows/** (4)
  • .github/workflows/linter.yaml
  • .github/workflows/release-please.yml
  • .github/workflows/unit-tests.yml
  • .github/workflows/update-a2a-types.yml
• Ignored by pattern: CHANGELOG.md (1)
  • CHANGELOG.md

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[github-actions]

🧪 Code Coverage (vs 1.0-dev)

⬇️ Download Full Report

	Base	PR	Delta
src/a2a/compat/v0_3/jsonrpc_adapter.py	31.06%	47.01%	🟢 +15.95%
src/a2a/compat/v0_3/rest_adapter.py	36.62%	50.70%	🟢 +14.08%
src/a2a/compat/v0_3/rest_handler.py	96.30%	96.67%	🟢 +0.37%
src/a2a/server/apps/jsonrpc/jsonrpc_app.py	87.07%	87.18%	🟢 +0.11%
src/a2a/server/request_handlers/jsonrpc_handler.py	92.00%	92.50%	🟢 +0.50%
src/a2a/server/request_handlers/rest_handler.py	93.02%	93.75%	🟢 +0.73%
src/a2a/utils/error_handlers.py	93.33%	95.65%	🟢 +2.32%
src/a2a/utils/helpers.py	100.00%	97.42%	🔴 -2.58%
Total	90.29%	90.77%	🟢 +0.48%

Generated by coverage-comment.yml

[gemini-code-assist]

Code Review

This pull request introduces a new validate_version decorator to enforce API versioning based on the A2A-Version header, applying it to various JSONRPC and REST handler methods for both v0.3 compatibility and v1.0 protocols. It also significantly improves error handling for streaming responses by refactoring the rest_stream_error_handler to catch exceptions that occur during the asynchronous generation of stream content, rather than just during the initial request. Accompanying these changes are updated imports, standardized test context creation, and comprehensive new test cases to validate the versioning logic and the enhanced streaming error handling.