Improve comments and revert much of 373cb20

test/core/end2end/inproc_callback_test.cc

@@ -106,7 +106,7 @@ bool tags_needed[kAvailableTags];
 
 // Mark that a tag is expected; this function must be executed in the
 // main thread only while there are no other threads altering the
-// expectation set (e.g., running callbacks).
+// expectation set (e.g., by calling expect_tag or verify_tags)
 static void expect_tag(intptr_t tag, bool ok) {
   size_t idx = static_cast<size_t>(tag);
   GPR_ASSERT(idx < kAvailableTags);
@@ -114,10 +114,14 @@ static void expect_tag(intptr_t tag, bool ok) {
   tags_expected[idx] = ok;
 }
 
-// The tag verifier doesn't have to drive the CQ at all (unlike the
-// next-based end2end tests) because the tags will get set when the
-// callbacks are executed, which happens when a particular batch
-// related to a callback is complete
+// Check that the expected tags have reached, within a certain
+// deadline. This must also be executed only on the main thread while
+// there are no other threads altering the expectation set (e.g., by
+// calling expect_tag or verify_tags). The tag verifier doesn't have
+// to drive the CQ at all (unlike the next-based end2end tests)
+// because the tags will get set when the callbacks are executed,
+// which happens when a particular batch related to a callback is
+// complete.
 static void verify_tags(gpr_timespec deadline) {
   bool done = false;
 
@@ -342,14 +346,13 @@ static void simple_request_body(grpc_end2end_test_config config,
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   // Register a call at the server-side to match the incoming client call
-  // First mark that we are expecting its tag to complete in this round
-  expect_tag(2, true);
   error = grpc_server_request_call(f.server, &s, &call_details,
                                    &request_metadata_recv, f.cq, f.cq, tag(2));
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   // We expect that the server call creation callback (and no others) will
   // execute now since no other batch should be complete.
+  expect_tag(2, true);
   verify_tags(deadline);
 
   peer = grpc_call_get_peer(s);
@@ -361,11 +364,6 @@ static void simple_request_body(grpc_end2end_test_config config,
   gpr_log(GPR_DEBUG, "client_peer=%s", peer);
   gpr_free(peer);
 
-  // Both the client request and server response batches should get complete
-  // in this round and we should see that their callbacks get executed
-  expect_tag(3, true);
-  expect_tag(1, true);
-
   // Create the server response batch (no payload)
   memset(ops, 0, sizeof(ops));
   op = ops;
@@ -391,7 +389,10 @@ static void simple_request_body(grpc_end2end_test_config config,
                                 nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
-  // Make sure that the tags get executed by the deadline
+  // Both the client request and server response batches should get complete
+  // now and we should see that their callbacks have been executed
+  expect_tag(3, true);
+  expect_tag(1, true);
   verify_tags(deadline);
 
   GPR_ASSERT(status == GRPC_STATUS_UNIMPLEMENTED);