re-enable rctx:sleep

looks like the IO refactor fixes it!

Author: dormando

proxy_lua.c

@@ -1659,7 +1659,7 @@ int proxy_register_libs(void *ctx, LIBEVENT_THREAD *t, void *state) {
         {"tls_peer_cn", mcplib_rcontext_tls_peer_cn},
         {"request_new", mcplib_rcontext_request_new},
         {"response_new", mcplib_rcontext_response_new},
-        //{"sleep", mcplib_rcontext_sleep}, see comments on function
+        {"sleep", mcplib_rcontext_sleep},
         {NULL, NULL}
     };
 

proxy_luafgen.c

@@ -1328,32 +1328,6 @@ int mcplib_rcontext_wait_handle(lua_State *L) {
     return lua_yield(L, 1);
 }
 
-// TODO: This is disabled due to issues with the IO subsystem. Fixing this
-// requires retiring of API1 to allow refactoring or some extra roundtrip
-// work.
-// - if rctx:sleep() is called, the coroutine is suspended.
-// - once resumed after the timeout, we may later suspend again and make
-// backend requests
-// - once the coroutine is completed, we need to check if the owning client
-// conn is ready to be resumed
-// - BUG: we can only get into the "conn is in IO queue wait" state if a
-// sub-IO was created and submitted somewhere.
-// - This means either rctx:sleep() needs to be implemented by submitting a
-// dummy IO req (as other code does)
-// - OR we need to refactor the IO system so the dummies aren't required
-// anymore.
-//
-// If a dummy is used, we would have to implement this as:
-// - immediately submit a dummy IO if sleep is called.
-// - this allows the IO system to move the connection into the right state
-// - will immediately circle back then set an alarm for the sleep timeout
-// - once the sleep resumes, run code as normal. resumption should work
-// properly since we've entered the correct state originally.
-//
-// This adds a lot of CPU overhead to sleep, which should be fine given the
-// nature of the function, but also adds a lot of code and increases the
-// chances of bugs. So I'm leaving it out until this can be implemented more
-// simply.
 int mcplib_rcontext_sleep(lua_State *L) {
     mcp_rcontext_t *rctx = lua_touserdata(L, 1);
     if (rctx->wait_mode != QWAIT_IDLE) {

t/proxyrctxtimeout.t

@@ -28,7 +28,6 @@ $t->set_c($ps);
 $t->accept_backends();
 
 subtest 'sleep' => sub {
-    plan skip_all => 'sleep does not work';
     $t->c_send("mg sleep/foo t\r\n");
     $t->be_recv_c(0, "near got request");
     $t->be_send(0, "HD t94\r\n");