From 74d1a46ef8ac13c2fbe43d4eaa2c5ea492eae644 Mon Sep 17 00:00:00 2001
From: "Mark D. Roth" <roth@google.com>
Date: Tue, 5 Dec 2017 11:00:21 -0800
Subject: [PATCH] Change inproc transport to set trailing_metadata_available.

---
 .../ext/transport/inproc/inproc_transport.cc  | 23 +++++++++++++++++++
 1 file changed, 23 insertions(+)

diff --git a/src/core/ext/transport/inproc/inproc_transport.cc b/src/core/ext/transport/inproc/inproc_transport.cc
index 25790608116..d8d753e4591 100644
--- a/src/core/ext/transport/inproc/inproc_transport.cc
+++ b/src/core/ext/transport/inproc/inproc_transport.cc
@@ -458,6 +458,14 @@ static void fail_helper_locked(grpc_exec_ctx* exec_ctx, inproc_stream* s,
     } else {
       err = GRPC_ERROR_REF(error);
     }
+    if (s->recv_initial_md_op->payload->recv_initial_metadata
+            .trailing_metadata_available != nullptr) {
+      // Set to true unconditionally, because we're failing the call, so even
+      // if we haven't actually seen the send_trailing_metadata op from the
+      // other side, we're going to return trailing metadata anyway.
+      *s->recv_initial_md_op->payload->recv_initial_metadata
+           .trailing_metadata_available = true;
+    }
     INPROC_LOG(GPR_DEBUG,
                "fail_helper %p scheduling initial-metadata-ready %p %p", s,
                error, err);
@@ -670,6 +678,12 @@ static void op_state_machine(grpc_exec_ctx* exec_ctx, void* arg,
           nullptr);
       s->recv_initial_md_op->payload->recv_initial_metadata
           .recv_initial_metadata->deadline = s->deadline;
+      if (s->recv_initial_md_op->payload->recv_initial_metadata
+              .trailing_metadata_available != nullptr) {
+        *s->recv_initial_md_op->payload->recv_initial_metadata
+             .trailing_metadata_available =
+            (other != nullptr && other->send_trailing_md_op != nullptr);
+      }
       grpc_metadata_batch_clear(exec_ctx, &s->to_read_initial_md);
       s->to_read_initial_md_filled = false;
       INPROC_LOG(GPR_DEBUG,
@@ -995,6 +1009,15 @@ static void perform_stream_op(grpc_exec_ctx* exec_ctx, grpc_transport* gt,
     if (error != GRPC_ERROR_NONE) {
       // Schedule op's closures that we didn't push to op state machine
       if (op->recv_initial_metadata) {
+        if (op->payload->recv_initial_metadata.trailing_metadata_available !=
+            nullptr) {
+          // Set to true unconditionally, because we're failing the call, so
+          // even if we haven't actually seen the send_trailing_metadata op
+          // from the other side, we're going to return trailing metadata
+          // anyway.
+          *op->payload->recv_initial_metadata.trailing_metadata_available =
+              true;
+        }
         INPROC_LOG(
             GPR_DEBUG,
             "perform_stream_op error %p scheduling initial-metadata-ready %p",