Add option to disable gzip grpc-accept-encoding (#349)

Rather than operating as a gRPC-aware HTTP proxy, Microsoft's `dapr` sidecar is apparently compressing and decompressing each proxied gRPC message. It's using grpc-go and doesn't appear to handle asymmetric compression, so this PR introduces a mechanism to disable gzip support in connect-go clients.

connect_ext_test.go

@@ -675,6 +675,28 @@ func TestCustomCompression(t *testing.T) {
 	assert.Equal(t, response.Msg, &pingv1.PingResponse{Text: request.Text})
 }
 
+func TestClientWithoutGzipSupport(t *testing.T) {
+	// See https://github.com/bufbuild/connect-go/pull/349 for why we want to
+	// support this. TL;DR is that Microsoft's dapr sidecar can't handle
+	// asymmetric compression.
+	t.Parallel()
+	mux := http.NewServeMux()
+	mux.Handle(pingv1connect.NewPingServiceHandler(pingServer{}))
+	server := httptest.NewServer(mux)
+	defer server.Close()
+
+	client := pingv1connect.NewPingServiceClient(server.Client(),
+		server.URL,
+		connect.WithAcceptCompression("gzip", nil, nil),
+		connect.WithSendGzip(),
+	)
+	request := &pingv1.PingRequest{Text: "gzip me!"}
+	_, err := client.Ping(context.Background(), connect.NewRequest(request))
+	assert.NotNil(t, err)
+	assert.Equal(t, connect.CodeOf(err), connect.CodeUnknown)
+	assert.True(t, strings.Contains(err.Error(), "unknown compression"))
+}
+
 func TestInvalidHeaderTimeout(t *testing.T) {
 	t.Parallel()
 	mux := http.NewServeMux()

option.go

@@ -36,16 +36,21 @@ type ClientOption interface {
 //
 // It's safe to use this option liberally: servers will ignore any
 // compression algorithms they don't support. To compress requests, pair this
-// option with [WithSendCompression].
+// option with [WithSendCompression]. To remove support for a
+// previously-registered compression algorithm, use WithAcceptCompression with
+// nil decompressor and compressor constructors.
 //
-// Clients accept gzipped requests by default, using a compressor backed by the
+// Clients accept gzipped responses by default, using a compressor backed by the
 // standard library's [gzip] package with the default compression level. Use
 // [WithSendGzip] to compress requests with gzip.
 func WithAcceptCompression(
 	name string,
 	newDecompressor func() Decompressor,
 	newCompressor func() Compressor,
 ) ClientOption {
+	if newDecompressor == nil && newCompressor == nil {
+		return &compressionOption{Name: name}
+	}
 	return &compressionOption{
 		Name:            name,
 		CompressionPool: newCompressionPool(newDecompressor, newCompressor),
@@ -298,7 +303,19 @@ type compressionOption struct {
 }
 
 func (o *compressionOption) applyToClient(config *clientConfig) {
-	if o.Name == "" || o.CompressionPool == nil {
+	if o.Name == "" {
+		return
+	}
+	if o.CompressionPool == nil {
+		delete(config.CompressionPools, o.Name)
+		var names []string
+		for _, name := range config.CompressionNames {
+			if name == o.Name {
+				continue
+			}
+			names = append(names, name)
+		}
+		config.CompressionNames = names
 		return
 	}
 	config.CompressionPools[o.Name] = o.CompressionPool