core: Clarify missing content-type on HTTP error responses#12720
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becomeStar wants to merge 1 commit intogrpc:masterfrom
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core: Clarify missing content-type on HTTP error responses#12720becomeStar wants to merge 1 commit intogrpc:masterfrom
becomeStar wants to merge 1 commit intogrpc:masterfrom
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Improve the client-side diagnostic for HTTP error responses that are missing `content-type`. grpc-java currently may report a missing header as `invalid content-type: null`. Keep the existing HTTP-to-gRPC status mapping unchanged and replace that detail with a more accurate message.
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Pull request overview
This PR improves gRPC-Java client diagnostics when an HTTP error response is missing the content-type header, replacing the misleading invalid content-type: null message while keeping the existing HTTP→gRPC status mapping unchanged (per #12418).
Changes:
- Adjust
Http2ClientStreamTransportState.validateInitialMetadata()to emitmissing content-type in response headerswhen the header is absent (null). - Preserve existing behavior/messages for invalid non-null content-type values.
- Add a regression test covering missing
content-typewith an HTTP 431 response.
Reviewed changes
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| File | Description |
|---|---|
| core/src/main/java/io/grpc/internal/Http2ClientStreamTransportState.java | Emits a clearer diagnostic when content-type is missing while keeping HTTP status mapping intact. |
| core/src/test/java/io/grpc/internal/Http2ClientStreamTransportStateTest.java | Adds test coverage for the missing content-type + HTTP 431 case. |
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Mar 23, 2026
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Summary
In this case, grpc-java preserves the HTTP status-based context, but may later append
invalid content-type: null.That seems misleading when the response is missing
content-type, because the header appears to be absent rather than invalid, and thenullvalue exposes a Java implementation detail.This PR keeps the existing HTTP-to-gRPC status mapping unchanged and only adjusts the diagnostic for the missing
content-typecase.Changes
invalid content-type: nullwithmissing content-type in response headersRef #12418