Add grpc compatibility test

common/baderror/baderror.go

@@ -0,0 +1,12 @@
+package baderror
+
+import "strings"
+
+func Contains(err error, msgList ...string) bool {
+	for _, msg := range msgList {
+		if strings.Contains(err.Error(), msg) {
+			return true
+		}
+	}
+	return false
+}

common/baderror/grpc.go

@@ -0,0 +1,26 @@
+package baderror
+
+import (
+	"context"
+	"io"
+	"net"
+)
+
+func WrapGRPC(err error) error {
+	// grpc uses stupid internal error types
+	if err == nil {
+		return nil
+	}
+	if Contains(err, "EOF") {
+		return io.EOF
+	}
+	if Contains(err, "Canceled") {
+		return context.Canceled
+	}
+	if Contains(err,
+		"the client connection is closing",
+		"server closed the stream without sending trailers") {
+		return net.ErrClosed
+	}
+	return err
+}

common/baderror/h2.go

@@ -0,0 +1,22 @@
+package baderror
+
+import (
+	"io"
+	"net"
+
+	E "github.com/sagernet/sing/common/exceptions"
+)
+
+func WrapH2(err error) error {
+	if err == nil {
+		return nil
+	}
+	err = E.Unwrap(err)
+	if err == io.ErrUnexpectedEOF {
+		return io.EOF
+	}
+	if Contains(err, "client disconnected", "body closed by handler") {
+		return net.ErrClosed
+	}
+	return err
+}