New Features

• Co::getContext to get the coroutine context object (RFC-1018) (@twose)
• Co::getPcid to get the parent coroutine ID (RFC-1017) (@twose)
• Co::exists to know if a coroutine exists (@twose)
• Runtime Coroutine Hook supports stream_select (#2358) (@matyhtf)
• max_wait_time configuration support in BASE mode (#2282) (@shiguangqi)
• Support for one-way delivery tasks in the Master/Manager/User process (RFC-1015) (@matyhtf)
• Co\Socket has two new APIs recvAll and sendAll to ensure complete receive/send data until completion or error (3700cbb) (@twose)
• Process supports the coroutine mode, please refer to (Use Coroutine in Process)
• Added Server->getCallback method to get the callback function of the specified name of the Server (@matyhtf)

Enhancement

• The default max number of connections is 100K (instead of 10K) now. If the system configuration is less than this number, use the system configuration first (3d2e387) (@twose)
• Optimize the code for the Timer module, which now runs faster and accepts any number of arguments (#2347) (@twose)
• Co::stats will show more information such as the number of events, the number of registered signals, the number of AIO tasks, etc. (@matyhtf)
• Co::getBackTrace with no params is equivalent to debug_backtrace (@twose)
• Co::listCoroutines is renamed to Co::list, but the original name is still reserved as an alias (Backward compatibility) (@twose)
• Table::exist, Server::exist are renamed to exists, but the original name is still reserved as aliases (Backward compatibility) (@twose)
• Redis will automatically authenticate and select the corresponding database when it is automatically reconnected. Add API: getOptions, getAuth, getDBNum (#2303) (fdac8a3) (@windrunner414 & @twose)
• The default Socket buffer size on FreeBSD should be 2M (750a29c) (@twose)
• Server->stats will show worker_dispatch_count which can get the number of requests submitted by the master to the current process. The number of requests in the queue can be got by worker_dispatch_count - worker_request_count (a353808) (@matyhtf)
• Remove Nghttp2 dependencies, no longer need to install it, configuring compilation parameters to open
• Coroutines now have no max nesting level limitation (there are no real nesting relations between coroutines) (5458cbc) (@twose)
• When the coroutine reaches the max limitation, the HTTP server will return a 503 error indicating that the service is temporarily unavailable (ebd377f) (@twose)
• defer will now accept a parameter whose value is the return value at the end of the coroutine (example) (@twose)

Fixed

• Fixed error when the task method passed a null argument (#2366) (@twose)
• Fixed Http client send big data incomplete (#2360) (@twose)
• Fixed the bug that unprocessed data in the buffer was lost when the TCP client used the eof protocol (a59ae39) (@twose)
• Fixed async security of Server Reload (022f859) (@matyhtf)
• Fixed the index value of the connection iterator (b066146) (@twose)
• Fixed the bug that Set-Cookie special characters are too long to be outputed (#2368) (@mabu233 & @twose)
• Fixed the bug that Http client did not decode the cookie (duplicated encode when sent) (069ca5d) (@twose)
• Fixed Http client download with timeout lead to coredump (#2377) (@matyhtf & @twose)
• Fixed __call and call_user_func* lead to coredump when calling MySQL client method (#2387) (@matyhtf)
• Fixed coredump when Http2 client header name passed in a number (#2375) (@mabu233)
• Fixed Swoole\Event::dispatch behavior not as expected (#2390) (@matyhtf)
• Fixed Socks5 proxy handshake failed (94ef96c) (@twose)
• Fixed a memory read error caused by a connection failure in a low-version Linux kernel (5adf625) (@matyhtf & @twose)
• Fixed the bug that the server used the timer in the BASE single-process mode not work (82eca13) (@twose)
• Fixed compilation failure due to unstable ZendAPI in low-version (768b8a7) (@shiguangqi)
• Fixed EINVAL when calling sendto (#2395) (@junwei)

Unsupported

• Create server or customs process after using async file IO are not allowed
• Create server or customs process in coroutine are not allowed

Removed

• Websocket\Server->exists only shows if the connection exists. Please use the isEstablished method to get if it is a Websocket client.
• Remove the swoole.fast_serialize configuration item
• Removed the PHP Warning when the Co\Client method return failed
• Remove the Server->gzip method
• Remove PicoHttpParser support

Remove async modules

Remove all async modules, separate asynchronous extensions to async-ext:

• Async functions
• MySQL
• Redis
• Http\Client
• Memory\Pool
• MsgQueue
• RingQueue