Panic when enabling gzip compression and decompression on both sides

[vbfox]

Bug Report

Version

tonic v0.5.2
tonic-build v0.5.2

Platform

MacOS client, Ubuntu 18.04.1 server

Crates

tonic

Description

When i'm connecting to a tonic server running with .accept_gzip().send_gzip() from a tonic client (Configured with .accept_gzip().send_gzip()) the following panic happens:

thread 'tokio-runtime-worker' panicked at 'internal error: entered unreachable code: message was compressed but `Streaming.encoding` was `None`. This is a bug in Tonic.

with a call stack looking like:

 at /rustc/5a19ffe1c2b99d9e09706cc286aad1ec0868eddb/library/core/src/panicking.rs:93:14
 15: 0x55f431a3aa1f - tonic::codec::decode::Streaming<T>::decode_chunk::{{closure}}::h719e8096eea665ab
 at /tmp/backend-rs/cargo-home/registry/src/github.com-1ecc6299db9ec823/tonic-0.5.2/src/codec/decode.rs:253:29
 16: 0x55f431a4313d - core::option::Option<T>::unwrap_or_else::h29e89e1abd973546
 at /rustc/5a19ffe1c2b99d9e09706cc286aad1ec0868eddb/library/core/src/option.rs:776:21
 17: 0x55f431a4313d - tonic::codec::decode::Streaming<T>::decode_chunk::hf9c4435208b8651e
 at /tmp/backend-rs/cargo-home/registry/src/github.com-1ecc6299db9ec823/tonic-0.5.2/src/codec/decode.rs:252:25
 18: 0x55f431a4313d - <tonic::codec::decode::Streaming<T> as futures_core::stream::Stream>::poll_next::hb0db8a78fb88befb
 at /tmp/backend-rs/cargo-home/registry/src/github.com-1ecc6299db9ec823/tonic-0.5.2/src/codec/decode.rs:305:33
 19: 0x55f4319e4226 - <core::pin::Pin<P> as futures_core::stream::Stream>::poll_next::h7062e518aec4ea9e
 at /tmp/backend-rs/cargo-home/registry/src/github.com-1ecc6299db9ec823/futures-core-0.3.17/src/stream.rs:120:9
 20: 0x55f4319e4226 - <S as futures_core::stream::TryStream>::try_poll_next::h72affe497d5efb72
 at /tmp/backend-rs/cargo-home/registry/src/github.com-1ecc6299db9ec823/futures-core-0.3.17/src/stream.rs:196:9
 21: 0x55f4319e4226 - futures_util::stream::try_stream::TryStreamExt::try_poll_next_unpin::h9e11ac983c3d6048
 at /tmp/backend-rs/cargo-home/registry/src/github.com-1ecc6299db9ec823/futures-util-0.3.17/src/stream/try_stream/mod.rs:998:9
 22: 0x55f4319e4226 - <futures_util::stream::try_stream::try_next::TryNext<St> as core::future::future::Future>::poll::h7903916b737babbd
 at /tmp/backend-rs/cargo-home/registry/src/github.com-1ecc6299db9ec823/futures-util-0.3.17/src/stream/try_stream/try_next.rs:32:9
 23: 0x55f4319e4226 - tonic::server::grpc::Grpc<T>::map_request_unary::{{closure}}::h585e5cb38347b6a9
 at /tmp/backend-rs/cargo-home/registry/src/github.com-1ecc6299db9ec823/tonic-0.5.2/src/server/grpc.rs:349:23
 24: 0x55f4319e4226 - <core::future::from_generator::GenFuture<T> as core::future::future::Future>::poll::h3b8286d3d7b50009
 at /rustc/5a19ffe1c2b99d9e09706cc286aad1ec0868eddb/library/core/src/future/mod.rs:80:19
 25: 0x55f4319e4226 - tonic::server::grpc::Grpc<T>::unary::{{closure}}::h14ab60ff4ab397ed
 at /tmp/backend-rs/cargo-home/registry/src/github.com-1ecc6299db9ec823/tonic-0.5.2/src/server/grpc.rs:185:29
 26: 0x55f4319e4226 - <core::future::from_generator::GenFuture<T> as core::future::future::Future>::poll::h681afa6e3228c7a5
 at /rustc/5a19ffe1c2b99d9e09706cc286aad1ec0868eddb/library/core/src/future/mod.rs:80:19
 27: 0x55f4319e4226 - <my_service as tower_service::Service<http::request::Request<B>>>::call::{{closure}}::hfdfe97bf1d8cee6a

[vbfox]

I didn't fully debug yet, but suspect from a quick read of the current code that there are 2 problems here:

• Setting send_gzip() on clients doesn't send the expected header
• Receiving a compressed message without any header shouldn't panic but respond as specified in https://grpc.github.io/grpc/core/md_doc_compression.html

  An ill-constructed message with its Compressed-Flag bit set but lacking a grpc-encoding entry different from identity in its metadata MUST fail with INTERNAL status, its associated description indicating the invalid Compressed-Flag condition.

[LucioFranco]

#763 fixes this