core: On unexpected EOS, mention whether the frame was empty

ejona86 · web-flow · commit 60d3e7c5362a · 2020-12-10T14:54:33.000-08:00
Empty DATA frames with EOS tell a stronger tale as to where the server
may have its bug.
diff --git a/core/src/main/java/io/grpc/internal/Http2ClientStreamTransportState.java b/core/src/main/java/io/grpc/internal/Http2ClientStreamTransportState.java
@@ -144,11 +144,17 @@ protected void transportDataReceived(ReadableBuffer frame, boolean endOfStream)
             new Metadata());
         return;
       }
+      int frameSize = frame.readableBytes();
       inboundDataReceived(frame);
       if (endOfStream) {
         // This is a protocol violation as we expect to receive trailers.
-        transportError =
-            Status.INTERNAL.withDescription("Received unexpected EOS on DATA frame from server.");
+        if (frameSize > 0) {
+          transportError = Status.INTERNAL
+              .withDescription("Received unexpected EOS on non-empty DATA frame from server");
+        } else {
+          transportError = Status.INTERNAL
+              .withDescription("Received unexpected EOS on empty DATA frame from server");
+        }
         transportErrorMetadata = new Metadata();
         transportReportStatus(transportError, false, transportErrorMetadata);
       }
