Merge branch 'master' into cq_create_api_changes

18 files changed, 69 insertions, 241 deletions

diff --git a/src/core/ext/client_channel/connector.h b/src/core/ext/client_channel/connector.h
index 9bff41f003..94b5fb5c9e 100644
--- a/src/core/ext/client_channel/connector.h
+++ b/src/core/ext/client_channel/connector.h
@@ -48,8 +48,6 @@ struct grpc_connector {
 typedef struct {
   /** set of pollsets interested in this connection */
   grpc_pollset_set *interested_parties;
-  /** initial connect string to send */
-  grpc_slice initial_connect_string;
   /** deadline for connection */
   gpr_timespec deadline;
   /** channel arguments (to be passed to transport) */
diff --git a/src/core/ext/client_channel/default_initial_connect_string.c b/src/core/ext/client_channel/default_initial_connect_string.c
deleted file mode 100644
index 6db82d84ef..0000000000
--- a/src/core/ext/client_channel/default_initial_connect_string.c
+++ /dev/null
@@ -1,38 +0,0 @@
-/*
- *
- * Copyright 2015, Google Inc.
- * All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
- *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
- *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
- *
- */
-
-#include <grpc/slice.h>
-#include "src/core/lib/iomgr/resolve_address.h"
-
-void grpc_set_default_initial_connect_string(grpc_resolved_address **addr,
-                                             grpc_slice *initial_str) {}
diff --git a/src/core/ext/client_channel/initial_connect_string.c b/src/core/ext/client_channel/initial_connect_string.c
deleted file mode 100644
index 8ebd06c458..0000000000
--- a/src/core/ext/client_channel/initial_connect_string.c
+++ /dev/null
@@ -1,52 +0,0 @@
-/*
- *
- * Copyright 2015, Google Inc.
- * All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
- *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
- *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
- *
- */
-
-#include "src/core/ext/client_channel/initial_connect_string.h"
-
-#include <stddef.h>
-
-extern void grpc_set_default_initial_connect_string(
-    grpc_resolved_address **addr, grpc_slice *initial_str);
-
-static grpc_set_initial_connect_string_func g_set_initial_connect_string_func =
-    grpc_set_default_initial_connect_string;
-
-void grpc_test_set_initial_connect_string_function(
-    grpc_set_initial_connect_string_func func) {
-  g_set_initial_connect_string_func = func;
-}
-
-void grpc_set_initial_connect_string(grpc_resolved_address **addr,
-                                     grpc_slice *initial_str) {
-  g_set_initial_connect_string_func(addr, initial_str);
-}
diff --git a/src/core/ext/client_channel/initial_connect_string.h b/src/core/ext/client_channel/initial_connect_string.h
deleted file mode 100644
index 876abea40e..0000000000
--- a/src/core/ext/client_channel/initial_connect_string.h
+++ /dev/null
@@ -1,50 +0,0 @@
-/*
- *
- * Copyright 2015, Google Inc.
- * All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
- *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
- *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
- *
- */
-
-#ifndef GRPC_CORE_EXT_CLIENT_CHANNEL_INITIAL_CONNECT_STRING_H
-#define GRPC_CORE_EXT_CLIENT_CHANNEL_INITIAL_CONNECT_STRING_H
-
-#include <grpc/slice.h>
-#include "src/core/lib/iomgr/resolve_address.h"
-
-typedef void (*grpc_set_initial_connect_string_func)(
-    grpc_resolved_address **addr, grpc_slice *initial_str);
-
-void grpc_test_set_initial_connect_string_function(
-    grpc_set_initial_connect_string_func func);
-
-/** Set a string to be sent once connected. Optionally reset addr. */
-void grpc_set_initial_connect_string(grpc_resolved_address **addr,
-                                     grpc_slice *connect_string);
-
-#endif /* GRPC_CORE_EXT_CLIENT_CHANNEL_INITIAL_CONNECT_STRING_H */
diff --git a/src/core/ext/client_channel/subchannel.c b/src/core/ext/client_channel/subchannel.c
index ed5029ea9a..e886fbc0cc 100644
--- a/src/core/ext/client_channel/subchannel.c
+++ b/src/core/ext/client_channel/subchannel.c
@@ -41,7 +41,6 @@
 #include <grpc/support/string_util.h>
 
 #include "src/core/ext/client_channel/client_channel.h"
-#include "src/core/ext/client_channel/initial_connect_string.h"
 #include "src/core/ext/client_channel/parse_address.h"
 #include "src/core/ext/client_channel/proxy_mapper_registry.h"
 #include "src/core/ext/client_channel/subchannel_index.h"
@@ -103,9 +102,6 @@ struct grpc_subchannel {
 
   grpc_subchannel_key *key;
 
-  /** initial string to send to peer */
-  grpc_slice initial_connect_string;
-
   /** set during connection */
   grpc_connect_out_args connecting_result;
 
@@ -215,7 +211,6 @@ static void subchannel_destroy(grpc_exec_ctx *exec_ctx, void *arg,
   grpc_subchannel *c = arg;
   gpr_free((void *)c->filters);
   grpc_channel_args_destroy(exec_ctx, c->args);
-  grpc_slice_unref_internal(exec_ctx, c->initial_connect_string);
   grpc_connectivity_state_destroy(exec_ctx, &c->state_tracker);
   grpc_connector_unref(exec_ctx, c->connector);
   grpc_pollset_set_destroy(exec_ctx, c->pollset_set);
@@ -333,7 +328,6 @@ grpc_subchannel *grpc_subchannel_create(grpc_exec_ctx *exec_ctx,
   c->pollset_set = grpc_pollset_set_create();
   grpc_resolved_address *addr = gpr_malloc(sizeof(*addr));
   grpc_get_subchannel_address_arg(exec_ctx, args->args, addr);
-  grpc_set_initial_connect_string(&addr, &c->initial_connect_string);
   grpc_resolved_address *new_address = NULL;
   grpc_channel_args *new_args = NULL;
   if (grpc_proxy_mappers_map_address(exec_ctx, addr, args->args, &new_address,
@@ -404,7 +398,6 @@ static void continue_connect_locked(grpc_exec_ctx *exec_ctx,
   args.interested_parties = c->pollset_set;
   args.deadline = c->next_attempt;
   args.channel_args = c->args;
-  args.initial_connect_string = c->initial_connect_string;
 
   grpc_connectivity_state_set(exec_ctx, &c->state_tracker,
                               GRPC_CHANNEL_CONNECTING, GRPC_ERROR_NONE,
diff --git a/src/core/ext/lb_policy/pick_first/pick_first.c b/src/core/ext/lb_policy/pick_first/pick_first.c
index e2a66d16bd..179dcd6eac 100644
--- a/src/core/ext/lb_policy/pick_first/pick_first.c
+++ b/src/core/ext/lb_policy/pick_first/pick_first.c
@@ -423,11 +423,13 @@ static grpc_lb_policy *create_pick_first(grpc_exec_ctx *exec_ctx,
               "This LB policy doesn't support user data. It will be ignored");
     }
 
+    static const char *keys_to_remove[] = {GRPC_ARG_SUBCHANNEL_ADDRESS};
     memset(&sc_args, 0, sizeof(grpc_subchannel_args));
     grpc_arg addr_arg =
         grpc_create_subchannel_address_arg(&addresses->addresses[i].address);
-    grpc_channel_args *new_args =
-        grpc_channel_args_copy_and_add(args->args, &addr_arg, 1);
+    grpc_channel_args *new_args = grpc_channel_args_copy_and_add_and_remove(
+        args->args, keys_to_remove, GPR_ARRAY_SIZE(keys_to_remove), &addr_arg,
+        1);
     gpr_free(addr_arg.value.string);
     sc_args.args = new_args;
     grpc_subchannel *subchannel = grpc_client_channel_factory_create_subchannel(
diff --git a/src/core/ext/lb_policy/round_robin/round_robin.c b/src/core/ext/lb_policy/round_robin/round_robin.c
index f2d1d46179..09562d30ed 100644
--- a/src/core/ext/lb_policy/round_robin/round_robin.c
+++ b/src/core/ext/lb_policy/round_robin/round_robin.c
@@ -709,11 +709,13 @@ static grpc_lb_policy *round_robin_create(grpc_exec_ctx *exec_ctx,
     /* Skip balancer addresses, since we only know how to handle backends. */
     if (addresses->addresses[i].is_balancer) continue;
 
+    static const char *keys_to_remove[] = {GRPC_ARG_SUBCHANNEL_ADDRESS};
     memset(&sc_args, 0, sizeof(grpc_subchannel_args));
     grpc_arg addr_arg =
         grpc_create_subchannel_address_arg(&addresses->addresses[i].address);
-    grpc_channel_args *new_args =
-        grpc_channel_args_copy_and_add(args->args, &addr_arg, 1);
+    grpc_channel_args *new_args = grpc_channel_args_copy_and_add_and_remove(
+        args->args, keys_to_remove, GPR_ARRAY_SIZE(keys_to_remove), &addr_arg,
+        1);
     gpr_free(addr_arg.value.string);
     sc_args.args = new_args;
     grpc_subchannel *subchannel = grpc_client_channel_factory_create_subchannel(
diff --git a/src/core/ext/transport/chttp2/client/chttp2_connector.c b/src/core/ext/transport/chttp2/client/chttp2_connector.c
index eae0145ecc..d49c32b671 100644
--- a/src/core/ext/transport/chttp2/client/chttp2_connector.c
+++ b/src/core/ext/transport/chttp2/client/chttp2_connector.c
@@ -63,8 +63,6 @@ typedef struct {
   grpc_closure *notify;
   grpc_connect_in_args args;
   grpc_connect_out_args *result;
-  grpc_closure initial_string_sent;
-  grpc_slice_buffer initial_string_buffer;
 
   grpc_endpoint *endpoint;  // Non-NULL until handshaking starts.
 
@@ -82,7 +80,6 @@ static void chttp2_connector_unref(grpc_exec_ctx *exec_ctx,
                                    grpc_connector *con) {
   chttp2_connector *c = (chttp2_connector *)con;
   if (gpr_unref(&c->refs)) {
-    /* c->initial_string_buffer does not need to be destroyed */
     gpr_mu_destroy(&c->mu);
     // If handshaking is not yet in progress, destroy the endpoint.
     // Otherwise, the handshaker will do this for us.
@@ -160,28 +157,6 @@ static void start_handshake_locked(grpc_exec_ctx *exec_ctx,
   c->endpoint = NULL;  // Endpoint handed off to handshake manager.
 }
 
-static void on_initial_connect_string_sent(grpc_exec_ctx *exec_ctx, void *arg,
-                                           grpc_error *error) {
-  chttp2_connector *c = arg;
-  gpr_mu_lock(&c->mu);
-  if (error != GRPC_ERROR_NONE || c->shutdown) {
-    if (error == GRPC_ERROR_NONE) {
-      error = GRPC_ERROR_CREATE("connector shutdown");
-    } else {
-      error = GRPC_ERROR_REF(error);
-    }
-    memset(c->result, 0, sizeof(*c->result));
-    grpc_closure *notify = c->notify;
-    c->notify = NULL;
-    grpc_closure_sched(exec_ctx, notify, error);
-    gpr_mu_unlock(&c->mu);
-    chttp2_connector_unref(exec_ctx, arg);
-  } else {
-    start_handshake_locked(exec_ctx, c);
-    gpr_mu_unlock(&c->mu);
-  }
-}
-
 static void connected(grpc_exec_ctx *exec_ctx, void *arg, grpc_error *error) {
   chttp2_connector *c = arg;
   gpr_mu_lock(&c->mu);
@@ -204,17 +179,7 @@ static void connected(grpc_exec_ctx *exec_ctx, void *arg, grpc_error *error) {
     chttp2_connector_unref(exec_ctx, arg);
   } else {
     GPR_ASSERT(c->endpoint != NULL);
-    if (!GRPC_SLICE_IS_EMPTY(c->args.initial_connect_string)) {
-      grpc_closure_init(&c->initial_string_sent, on_initial_connect_string_sent,
-                        c, grpc_schedule_on_exec_ctx);
-      grpc_slice_buffer_init(&c->initial_string_buffer);
-      grpc_slice_buffer_add(&c->initial_string_buffer,
-                            c->args.initial_connect_string);
-      grpc_endpoint_write(exec_ctx, c->endpoint, &c->initial_string_buffer,
-                          &c->initial_string_sent);
-    } else {
-      start_handshake_locked(exec_ctx, c);
-    }
+    start_handshake_locked(exec_ctx, c);
     gpr_mu_unlock(&c->mu);
   }
 }
diff --git a/src/core/ext/transport/cronet/transport/cronet_transport.c b/src/core/ext/transport/cronet/transport/cronet_transport.c
index 450d9ab23a..36bb67869c 100644
--- a/src/core/ext/transport/cronet/transport/cronet_transport.c
+++ b/src/core/ext/transport/cronet/transport/cronet_transport.c
@@ -128,6 +128,7 @@ struct read_state {
   int received_bytes;
   int remaining_bytes;
   int length_field;
+  bool compressed;
   char grpc_header_bytes[GRPC_HEADER_SIZE_IN_BYTES];
   char *payload_field;
   bool read_stream_closed;
@@ -484,6 +485,16 @@ static void on_response_headers_received(
   CRONET_LOG(GPR_DEBUG, "R: on_response_headers_received(%p, %p, %s)", stream,
              headers, negotiated_protocol);
   stream_obj *s = (stream_obj *)stream->annotation;
+
+  /* Identify if this is a header or a trailer (in a trailer-only response case)
+   */
+  for (size_t i = 0; i < headers->count; i++) {
+    if (0 == strcmp("grpc-status", headers->headers[i].key)) {
+      on_response_trailers_received(stream, headers);
+      return;
+    }
+  }
+
   gpr_mu_lock(&s->mu);
   memset(&s->state.rs.initial_metadata, 0,
          sizeof(s->state.rs.initial_metadata));
@@ -507,6 +518,7 @@ static void on_response_headers_received(
      is closed */
     GPR_ASSERT(s->state.rs.length_field_received == false);
     s->state.rs.read_buffer = s->state.rs.grpc_header_bytes;
+    s->state.rs.compressed = false;
     s->state.rs.received_bytes = 0;
     s->state.rs.remaining_bytes = GRPC_HEADER_SIZE_IN_BYTES;
     CRONET_LOG(GPR_DEBUG, "bidirectional_stream_read(%p)", s->cbs);
@@ -641,7 +653,7 @@ static void on_response_trailers_received(
 */
 static void create_grpc_frame(grpc_slice_buffer *write_slice_buffer,
                               char **pp_write_buffer,
-                              size_t *p_write_buffer_size) {
+                              size_t *p_write_buffer_size, uint32_t flags) {
   grpc_slice slice = grpc_slice_buffer_take_first(write_slice_buffer);
   size_t length = GRPC_SLICE_LENGTH(slice);
   *p_write_buffer_size = length + GRPC_HEADER_SIZE_IN_BYTES;
@@ -650,7 +662,9 @@ static void create_grpc_frame(grpc_slice_buffer *write_slice_buffer,
   *pp_write_buffer = write_buffer;
   uint8_t *p = (uint8_t *)write_buffer;
   /* Append 5 byte header */
-  *p++ = 0;
+  /* Compressed flag */
+  *p++ = (flags & GRPC_WRITE_INTERNAL_COMPRESS) ? 1 : 0;
+  /* Message length */
   *p++ = (uint8_t)(length >> 24);
   *p++ = (uint8_t)(length >> 16);
   *p++ = (uint8_t)(length >> 8);
@@ -728,14 +742,16 @@ static void convert_metadata_to_cronet_headers(
   *p_num_headers = (size_t)num_headers;
 }
 
-static int parse_grpc_header(const uint8_t *data) {
+static void parse_grpc_header(const uint8_t *data, int *length,
+                              bool *compressed) {
+  const uint8_t c = *data;
   const uint8_t *p = data + 1;
-  int length = 0;
-  length |= ((uint8_t)*p++) << 24;
-  length |= ((uint8_t)*p++) << 16;
-  length |= ((uint8_t)*p++) << 8;
-  length |= ((uint8_t)*p++);
-  return length;
+  *compressed = ((c & 0x01) == 0x01);
+  *length = 0;
+  *length |= ((uint8_t)*p++) << 24;
+  *length |= ((uint8_t)*p++) << 16;
+  *length |= ((uint8_t)*p++) << 8;
+  *length |= ((uint8_t)*p++);
 }
 
 static bool header_has_authority(grpc_linked_mdelem *head) {
@@ -788,7 +804,8 @@ static bool op_can_be_run(grpc_transport_stream_op *curr_op,
     else if (!stream_state->state_callback_received[OP_SEND_INITIAL_METADATA])
       result = false;
     /* we haven't received headers yet. */
-    else if (!stream_state->state_callback_received[OP_RECV_INITIAL_METADATA])
+    else if (!stream_state->state_callback_received[OP_RECV_INITIAL_METADATA] &&
+             !stream_state->state_op_done[OP_RECV_TRAILING_METADATA])
       result = false;
   } else if (op_id == OP_SEND_MESSAGE) {
     /* already executed (note we're checking op specific state, not stream
@@ -801,7 +818,8 @@ static bool op_can_be_run(grpc_transport_stream_op *curr_op,
     /* already executed */
     if (op_state->state_op_done[OP_RECV_MESSAGE]) result = false;
     /* we haven't received headers yet. */
-    else if (!stream_state->state_callback_received[OP_RECV_INITIAL_METADATA])
+    else if (!stream_state->state_callback_received[OP_RECV_INITIAL_METADATA] &&
+             !stream_state->state_op_done[OP_RECV_TRAILING_METADATA])
       result = false;
   } else if (op_id == OP_RECV_TRAILING_METADATA) {
     /* already executed */
@@ -955,12 +973,6 @@ static enum e_op_result execute_stream_op(grpc_exec_ctx *exec_ctx,
       grpc_slice_buffer_init(&write_slice_buffer);
       grpc_byte_stream_next(NULL, stream_op->send_message, &slice,
                             stream_op->send_message->length, NULL);
-      /* Check that compression flag is OFF. We don't support compression yet.
-       */
-      if (stream_op->send_message->flags != 0) {
-        gpr_log(GPR_ERROR, "Compression is not supported");
-        GPR_ASSERT(stream_op->send_message->flags == 0);
-      }
       grpc_slice_buffer_add(&write_slice_buffer, slice);
       if (write_slice_buffer.count != 1) {
         /* Empty request not handled yet */
@@ -970,7 +982,7 @@ static enum e_op_result execute_stream_op(grpc_exec_ctx *exec_ctx,
       if (write_slice_buffer.count > 0) {
         size_t write_buffer_size;
         create_grpc_frame(&write_slice_buffer, &stream_state->ws.write_buffer,
-                          &write_buffer_size);
+                          &write_buffer_size, stream_op->send_message->flags);
         CRONET_LOG(GPR_DEBUG, "bidirectional_stream_write (%p, %p)", s->cbs,
                    stream_state->ws.write_buffer);
         stream_state->state_callback_received[OP_SEND_MESSAGE] = false;
@@ -1022,6 +1034,9 @@ static enum e_op_result execute_stream_op(grpc_exec_ctx *exec_ctx,
     } else if (stream_state->state_callback_received[OP_FAILED]) {
       grpc_closure_sched(exec_ctx, stream_op->recv_initial_metadata_ready,
                          GRPC_ERROR_NONE);
+    } else if (stream_state->state_op_done[OP_RECV_TRAILING_METADATA]) {
+      grpc_closure_sched(exec_ctx, stream_op->recv_initial_metadata_ready,
+                         GRPC_ERROR_NONE);
     } else {
       grpc_chttp2_incoming_metadata_buffer_publish(
           exec_ctx, &oas->s->state.rs.initial_metadata,
@@ -1066,8 +1081,9 @@ static enum e_op_result execute_stream_op(grpc_exec_ctx *exec_ctx,
           stream_state->rs.remaining_bytes == 0) {
         /* Start a read operation for data */
         stream_state->rs.length_field_received = true;
-        stream_state->rs.length_field = stream_state->rs.remaining_bytes =
-            parse_grpc_header((const uint8_t *)stream_state->rs.read_buffer);
+        parse_grpc_header((const uint8_t *)stream_state->rs.read_buffer,
+                          &stream_state->rs.length_field,
+                          &stream_state->rs.compressed);
         CRONET_LOG(GPR_DEBUG, "length field = %d",
                    stream_state->rs.length_field);
         if (stream_state->rs.length_field > 0) {
@@ -1089,6 +1105,9 @@ static enum e_op_result execute_stream_op(grpc_exec_ctx *exec_ctx,
           grpc_slice_buffer_init(&stream_state->rs.read_slice_buffer);
           grpc_slice_buffer_stream_init(&stream_state->rs.sbs,
                                         &stream_state->rs.read_slice_buffer, 0);
+          if (stream_state->rs.compressed) {
+            stream_state->rs.sbs.base.flags |= GRPC_WRITE_INTERNAL_COMPRESS;
+          }
           *((grpc_byte_buffer **)stream_op->recv_message) =
               (grpc_byte_buffer *)&stream_state->rs.sbs;
           grpc_closure_sched(exec_ctx, stream_op->recv_message_ready,
@@ -1100,6 +1119,7 @@ static enum e_op_result execute_stream_op(grpc_exec_ctx *exec_ctx,
           stream_state->rs.read_buffer = stream_state->rs.grpc_header_bytes;
           stream_state->rs.remaining_bytes = GRPC_HEADER_SIZE_IN_BYTES;
           stream_state->rs.received_bytes = 0;
+          stream_state->rs.compressed = false;
           stream_state->rs.length_field_received = false;
           CRONET_LOG(GPR_DEBUG, "bidirectional_stream_read(%p)", s->cbs);
           stream_state->state_op_done[OP_READ_REQ_MADE] =
@@ -1114,6 +1134,7 @@ static enum e_op_result execute_stream_op(grpc_exec_ctx *exec_ctx,
         stream_state->rs.read_buffer = stream_state->rs.grpc_header_bytes;
         stream_state->rs.remaining_bytes = GRPC_HEADER_SIZE_IN_BYTES;
         stream_state->rs.received_bytes = 0;
+        stream_state->rs.compressed = false;
         CRONET_LOG(GPR_DEBUG, "bidirectional_stream_read(%p)", s->cbs);
         stream_state->state_op_done[OP_READ_REQ_MADE] =
             true; /* Indicates that at least one read request has been made */
@@ -1137,6 +1158,9 @@ static enum e_op_result execute_stream_op(grpc_exec_ctx *exec_ctx,
                             read_data_slice);
       grpc_slice_buffer_stream_init(&stream_state->rs.sbs,
                                     &stream_state->rs.read_slice_buffer, 0);
+      if (stream_state->rs.compressed) {
+        stream_state->rs.sbs.base.flags = GRPC_WRITE_INTERNAL_COMPRESS;
+      }
       *((grpc_byte_buffer **)stream_op->recv_message) =
           (grpc_byte_buffer *)&stream_state->rs.sbs;
       grpc_closure_sched(exec_ctx, stream_op->recv_message_ready,
@@ -1146,6 +1170,7 @@ static enum e_op_result execute_stream_op(grpc_exec_ctx *exec_ctx,
       /* Do an extra read to trigger on_succeeded() callback in case connection
          is closed */
       stream_state->rs.read_buffer = stream_state->rs.grpc_header_bytes;
+      stream_state->rs.compressed = false;
       stream_state->rs.received_bytes = 0;
       stream_state->rs.remaining_bytes = GRPC_HEADER_SIZE_IN_BYTES;
       stream_state->rs.length_field_received = false;
diff --git a/src/core/lib/iomgr/closure.c b/src/core/lib/iomgr/closure.c
index 509c1ff95d..6633fb68ec 100644
--- a/src/core/lib/iomgr/closure.c
+++ b/src/core/lib/iomgr/closure.c
@@ -33,6 +33,7 @@
 
 #include "src/core/lib/iomgr/closure.h"
 
+#include <assert.h>
 #include <grpc/support/alloc.h>
 #include <grpc/support/log.h>
 
@@ -124,6 +125,7 @@ void grpc_closure_run(grpc_exec_ctx *exec_ctx, grpc_closure *c,
                       grpc_error *error) {
   GPR_TIMER_BEGIN("grpc_closure_run", 0);
   if (c != NULL) {
+    assert(c->cb);
     c->scheduler->vtable->run(exec_ctx, c, error);
   } else {
     GRPC_ERROR_UNREF(error);
@@ -135,6 +137,7 @@ void grpc_closure_sched(grpc_exec_ctx *exec_ctx, grpc_closure *c,
                         grpc_error *error) {
   GPR_TIMER_BEGIN("grpc_closure_sched", 0);
   if (c != NULL) {
+    assert(c->cb);
     c->scheduler->vtable->sched(exec_ctx, c, error);
   } else {
     GRPC_ERROR_UNREF(error);
@@ -146,6 +149,7 @@ void grpc_closure_list_sched(grpc_exec_ctx *exec_ctx, grpc_closure_list *list) {
   grpc_closure *c = list->head;
   while (c != NULL) {
     grpc_closure *next = c->next_data.next;
+    assert(c->cb);
     c->scheduler->vtable->sched(exec_ctx, c, c->error_data.error);
     c = next;
   }
diff --git a/src/core/lib/iomgr/combiner.c b/src/core/lib/iomgr/combiner.c
index fa9966c3a6..2bc476bbef 100644
--- a/src/core/lib/iomgr/combiner.c
+++ b/src/core/lib/iomgr/combiner.c
@@ -33,6 +33,7 @@
 
 #include "src/core/lib/iomgr/combiner.h"
 
+#include <assert.h>
 #include <string.h>
 
 #include <grpc/support/alloc.h>
@@ -216,6 +217,7 @@ static void combiner_exec(grpc_exec_ctx *exec_ctx, grpc_combiner *lock,
       GPR_DEBUG, "C:%p grpc_combiner_execute c=%p cov=%d last=%" PRIdPTR, lock,
       cl, covered_by_poller, last));
   GPR_ASSERT(last & STATE_UNORPHANED);  // ensure lock has not been destroyed
+  assert(cl->cb);
   cl->error_data.scratch =
       pack_error_data((error_data){error, covered_by_poller});
   if (covered_by_poller) {
diff --git a/src/core/lib/iomgr/error.h b/src/core/lib/iomgr/error.h
index eb953947ae..0e7a7b0a1e 100644
--- a/src/core/lib/iomgr/error.h
+++ b/src/core/lib/iomgr/error.h
@@ -45,28 +45,9 @@ extern "C" {
 #endif
 
 /// Opaque representation of an error.
-/// Errors are refcounted objects that represent the result of an operation.
-/// Ownership laws:
-///  if a grpc_error is returned by a function, the caller owns a ref to that
-///    instance
-///  if a grpc_error is passed to a grpc_closure callback function (functions
-///    with the signature:
-///      void (*f)(grpc_exec_ctx *exec_ctx, void *arg, grpc_error *error))
-///    then those functions do not own a ref to error (but are free to manually
-///    take a reference).
-///  if a grpc_error is passed to *ANY OTHER FUNCTION* then that function takes
-///    ownership of the error
-/// Errors have:
-///  a set of ints, strings, and timestamps that describe the error
-///  always present are:
-///    GRPC_ERROR_STR_FILE, GRPC_ERROR_INT_FILE_LINE - source location the error
-///      was generated
-///    GRPC_ERROR_STR_DESCRIPTION - a human readable description of the error
-///    GRPC_ERROR_TIME_CREATED - a timestamp indicating when the error happened
-///  an error can also have children; these are other errors that are believed
-///    to have contributed to this one. By accumulating children, we can begin
-///    to root cause high level failures from low level failures, without having
-///    to derive execution paths from log lines
+/// See https://github.com/grpc/grpc/blob/master/doc/core/grpc-error.md for a
+/// full write up of this object.
+
 typedef struct grpc_error grpc_error;
 
 typedef enum {
diff --git a/src/core/lib/iomgr/ev_poll_posix.c b/src/core/lib/iomgr/ev_poll_posix.c
index 5ddd5313e2..789ef22c55 100644
--- a/src/core/lib/iomgr/ev_poll_posix.c
+++ b/src/core/lib/iomgr/ev_poll_posix.c
@@ -1421,7 +1421,7 @@ static int cvfd_poll(struct pollfd *fds, nfds_t nfds, int timeout) {
     g_cvfds.pollcount++;
     opt = gpr_thd_options_default();
     gpr_thd_options_set_detached(&opt);
-    gpr_thd_new(&t_id, &run_poll, pargs, &opt);
+    GPR_ASSERT(gpr_thd_new(&t_id, &run_poll, pargs, &opt));
     // We want the poll() thread to trigger the deadline, so wait forever here
     gpr_cv_wait(pollcv, &g_cvfds.mu, gpr_inf_future(GPR_CLOCK_MONOTONIC));
     if (gpr_atm_no_barrier_load(&pargs->status) == COMPLETED) {
diff --git a/src/core/lib/iomgr/executor.c b/src/core/lib/iomgr/executor.c
index a5b62aa888..ae3e2eabc3 100644
--- a/src/core/lib/iomgr/executor.c
+++ b/src/core/lib/iomgr/executor.c
@@ -115,8 +115,8 @@ static void maybe_spawn_locked() {
   /* All previous instances of the thread should have been joined at this point.
    * Spawn time! */
   g_executor.busy = 1;
-  gpr_thd_new(&g_executor.tid, closure_exec_thread_func, NULL,
-              &g_executor.options);
+  GPR_ASSERT(gpr_thd_new(&g_executor.tid, closure_exec_thread_func, NULL,
+                         &g_executor.options));
   g_executor.pending_join = 1;
 }
 
diff --git a/src/core/lib/profiling/basic_timers.c b/src/core/lib/profiling/basic_timers.c
index 1f1987fb8e..bc8e27714c 100644
--- a/src/core/lib/profiling/basic_timers.c
+++ b/src/core/lib/profiling/basic_timers.c
@@ -218,7 +218,7 @@ void gpr_timers_set_log_filename(const char *filename) {
 static void init_output() {
   gpr_thd_options options = gpr_thd_options_default();
   gpr_thd_options_set_joinable(&options);
-  gpr_thd_new(&g_writing_thread, writing_thread, NULL, &options);
+  GPR_ASSERT(gpr_thd_new(&g_writing_thread, writing_thread, NULL, &options));
   atexit(finish_writing);
 }
 
diff --git a/src/core/lib/security/transport/server_auth_filter.c b/src/core/lib/security/transport/server_auth_filter.c
index 01cb473177..c47fe56ba4 100644
--- a/src/core/lib/security/transport/server_auth_filter.c
+++ b/src/core/lib/security/transport/server_auth_filter.c
@@ -158,7 +158,7 @@ static void auth_on_recv(grpc_exec_ctx *exec_ctx, void *user_data,
   call_data *calld = elem->call_data;
   channel_data *chand = elem->channel_data;
   if (error == GRPC_ERROR_NONE) {
-    if (chand->creds->processor.process != NULL) {
+    if (chand->creds != NULL && chand->creds->processor.process != NULL) {
       calld->md = metadata_batch_to_md_array(calld->recv_initial_metadata);
       chand->creds->processor.process(
           chand->creds->processor.state, calld->auth_context,
@@ -242,7 +242,6 @@ static grpc_error *init_channel_elem(grpc_exec_ctx *exec_ctx,
 
   GPR_ASSERT(!args->is_last);
   GPR_ASSERT(auth_context != NULL);
-  GPR_ASSERT(creds != NULL);
 
   /* initialize members */
   chand->auth_context =
diff --git a/src/objective-c/tests/CoreCronetEnd2EndTests/CoreCronetEnd2EndTests.m b/src/objective-c/tests/CoreCronetEnd2EndTests/CoreCronetEnd2EndTests.m
index 7656fb8d51..c1bf4ce4e8 100644
--- a/src/objective-c/tests/CoreCronetEnd2EndTests/CoreCronetEnd2EndTests.m
+++ b/src/objective-c/tests/CoreCronetEnd2EndTests/CoreCronetEnd2EndTests.m
@@ -274,8 +274,7 @@ static char *roots_filename;
 }
 
 - (void)testCompressedPayload {
-  // NOT SUPPORTED
-  // [self testIndividualCase:"compressed_payload"];
+  [self testIndividualCase:"compressed_payload"];
 }
 
 - (void)testConnectivity {
diff --git a/src/python/grpcio/grpc_core_dependencies.py b/src/python/grpcio/grpc_core_dependencies.py
index 8edab1b759..cb6ca34dc6 100644
--- a/src/python/grpcio/grpc_core_dependencies.py
+++ b/src/python/grpcio/grpc_core_dependencies.py
@@ -255,10 +255,8 @@ CORE_SOURCE_FILES = [
   'src/core/ext/client_channel/client_channel_factory.c',
   'src/core/ext/client_channel/client_channel_plugin.c',
   'src/core/ext/client_channel/connector.c',
-  'src/core/ext/client_channel/default_initial_connect_string.c',
   'src/core/ext/client_channel/http_connect_handshaker.c',
   'src/core/ext/client_channel/http_proxy.c',
-  'src/core/ext/client_channel/initial_connect_string.c',
   'src/core/ext/client_channel/lb_policy.c',
   'src/core/ext/client_channel/lb_policy_factory.c',
   'src/core/ext/client_channel/lb_policy_registry.c',