fix(a2a-pb): ignore unknown fields in ProtoJSON decode (spec §5.7)#81
fix(a2a-pb): ignore unknown fields in ProtoJSON decode (spec §5.7)#81arkavo-com wants to merge 1 commit into
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Spec §5.7: "Implementations SHOULD ignore unrecognized fields in messages, allowing for forward compatibility." The pbjson-generated deserializers rejected any unknown field, so a peer sending forward-compatible extra fields caused a local deserialize error on otherwise valid results. Enable pbjson_build's ignore_unknown_fields() so unknown fields are skipped during deserialization. Unknown enum string values are still rejected (ignore_unknown_enum_variants is intentionally not enabled). The post-generation null-repeated-field patches apply unchanged. The generated serde code lives in OUT_DIR (not the committed src/gen sources), so the committed files are unaffected. The server-side invalid-params test previously used a merely-unknown field as its bad-params fixture; that is now valid per §5.7, so it uses a genuine type mismatch instead, and a new test pins the unknown-field tolerance end to end. Found by cross-SDK interop testing (a2a-conformance).
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Code Review
This pull request configures the pbjson builder to ignore unrecognized fields in messages to ensure forward compatibility per Spec §5.7. It also adds tests to verify that unknown fields are ignored at both top-level and nested levels, while unknown enum string values are still rejected. Additionally, the JSON-RPC tests are updated to align with this new behavior. There are no review comments, so I have no feedback to provide.
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Adopt the WebSocket transport (new a2a-websocket crate: client + server + common + errors + e2e tests) from upstream PR a2aproject#63, rebased onto the current tree: brought in the self-contained crate + supporting a2a/types + proto, regenerated the protobuf rather than merging generated code, and merged the workspace deps. Fixed 4 server tests whose unknown-field payloads ({"bogus":true}, etc.) no longer error now that ProtoJSON ignores unknown fields per spec §5.7 (cherry a2aproject#81) — switched them to malformed non-object payloads so they still exercise the INVALID_PARAMS path. 105 unit + 8 integration tests pass; clippy clean. Co-authored-by: amitami2 <amitami2@cisco.com> Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com> Signed-off-by: ss <andrew@88plug.com>
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Problem
Spec §5.7: "Implementations SHOULD ignore unrecognized fields in messages, allowing for forward compatibility as the protocol evolves." The pbjson-generated deserializers reject unknown fields, so any peer that sends a forward-compatible extra field (or a newer protocol revision) fails to decode.
Fix
One line in
a2a-pb/build.rs:.ignore_unknown_fields()on thepbjson_build::Builder(supported by the pbjson-build 0.9.0 already in the workspace). Unknown fields now route to the generated__SkipField__arm. All existing post-generation replacements (NULL_REPEATED_FIELD_REPLACEMENTS, map handling) still match — the generated serde code lives inOUT_DIR, so no committed generated files change.ignore_unknown_enum_variantsis deliberately not enabled: unknown enum string values still error, preserving strictness where the spec doesn't ask for leniency.Heads-up for review: one existing test fixture changed
a2a-server'stest_invalid_paramsused{"bogus": true}— a merely-unknown field — as its invalid-params fixture. Under §5.7 semantics that payload is now valid (decodes to a default request). The test now uses a genuine type mismatch ({"message": "not-an-object"}) with the same error-code assertion, and a newtest_unknown_params_fields_are_ignoredpins the tolerance end-to-end through the JSON-RPC server.Found by / verified with
Cross-SDK interop testing (a2a-conformance, scenario
edge/unknown-field-tolerance; FINDINGS.md finding 2). New round-trip tests ina2a-pb/tests/(unknown top-level + nested fields accepted; unknown enum values still rejected);cargo test --workspace450 passed / 0 failed (baseline 447/0); fmt + clippy clean.🤖 Generated with Claude Code