Merge pull request #12953 from vjpai/sanitized_non_polling

Sanity check that tests declared non-polling actually don't poll

src/core/lib/iomgr/ev_posix.cc

@@ -61,12 +61,30 @@ typedef struct {
   event_engine_factory_fn factory;
 } event_engine_factory;
 
+namespace {
+extern "C" {
+int dummypoll(struct pollfd fds[], nfds_t nfds, int timeout) {
+  gpr_log(GPR_ERROR, "Attempted to poll despite declaring non-polling.");
+  GPR_ASSERT(false);
+  return -1;
+}
+}  // extern "C"
+
+const grpc_event_engine_vtable *init_non_polling(bool explicit_request) {
+  // return the simplest engine as a dummy but also override the poller
+  auto ret = grpc_init_poll_posix(explicit_request);
+  grpc_poll_function = dummypoll;
+  return ret;
+}
+}  // namespace
+
 static const event_engine_factory g_factories[] = {
     {"epoll1", grpc_init_epoll1_linux},
     {"epollsig", grpc_init_epollsig_linux},
     {"poll", grpc_init_poll_posix},
     {"poll-cv", grpc_init_poll_cv_posix},
     {"epollex", grpc_init_epollex_linux},
+    {"none", init_non_polling},
 };
 
 static void add(const char *beg, const char *end, char ***ss, size_t *ns) {

tools/run_tests/generated/tests.json

@@ -3811,7 +3811,8 @@
       "mac", 
       "posix", 
       "windows"
-    ]
+    ], 
+    "uses_polling": true
   }, 
   {
     "args": [], 

tools/run_tests/run_tests.py

@@ -286,7 +286,7 @@ class CLanguage(object):
         continue
       polling_strategies = (_POLLING_STRATEGIES.get(self.platform, ['all'])
                             if target.get('uses_polling', True)
-                            else ['all'])
+                            else ['none'])
       if self.args.iomgr_platform == 'uv':
         polling_strategies = ['all']
       for polling_strategy in polling_strategies: