We can't use arc with PHP 8.4:
$ arc paste P369 PHP Deprecated: Constant E_STRICT is deprecated in /opt/phabricator/arcanist/support/init/init-script.php on line 18 Deprecated: Constant E_STRICT is deprecated in /opt/phabricator/arcanist/support/init/init-script.php on line 18 [2025-03-27 18:31:15] EXCEPTION: (Exception) Error while loading file "/opt/phabricator/arcanist/src/future/FutureProxy.php": FutureProxy::__construct(): Implicitly marking parameter $proxied as nullable is deprecated, the explicit nullable type must be used instead at [<arcanist>/src/init/lib/PhutilBootloader.php:275] arcanist(head=production, ref.master=e50d1bc4eaba, ref.production=a1c7b85f1358), shellcheck-linter(head=main, ref.main=402dcb215451) #0 __phutil_autoload(string) called at [<arcanist>/src/conduit/ConduitFuture.php:3] #1 include_once(string) called at [<arcanist>/src/init/lib/PhutilBootloader.php:247] #2 PhutilBootloader::executeInclude(string) called at [<arcanist>/src/init/lib/PhutilBootloader.php:207] #3 PhutilBootloader::loadLibrarySource(string, string) called at [<arcanist>/src/symbols/PhutilSymbolLoader.php:423] #4 PhutilSymbolLoader::loadSymbol(array) called at [<arcanist>/src/symbols/PhutilSymbolLoader.php:277] #5 PhutilSymbolLoader::selectAndLoadSymbols() called at [<arcanist>/src/init/init-library.php:23] #6 __phutil_autoload(string) called at [<arcanist>/src/conduit/ConduitClient.php:180] #7 ConduitClient::callMethod(string, array) called at [<arcanist>/src/conduit/ArcanistConduitEngine.php:47] #8 ArcanistConduitEngine::newFuture(string, array) called at [<arcanist>/src/conduit/ConduitSearchFuture.php:107] #9 ConduitSearchFuture::newFuture() called at [<arcanist>/src/conduit/ConduitSearchFuture.php:59] #10 ConduitSearchFuture::isReady() called at [<arcanist>/src/future/Future.php:63] #11 Future::updateFuture() called at [<arcanist>/src/future/Future.php:159] #12 Future::start() called at [<arcanist>/src/future/FutureIterator.php:403] #13 FutureIterator::moveFutureToWork(string) called at [<arcanist>/src/future/FutureIterator.php:374] #14 FutureIterator::updateWorkingSet() called at [<arcanist>/src/future/FutureIterator.php:206] #15 FutureIterator::next() called at [<arcanist>/src/future/FutureIterator.php:190] #16 FutureIterator::rewind() called at [<arcanist>/src/hardpoint/ArcanistHardpointEngine.php:213] #17 ArcanistHardpointEngine::updateFutures() called at [<arcanist>/src/hardpoint/ArcanistHardpointEngine.php:176] #18 ArcanistHardpointEngine::waitForRequests(array) called at [<arcanist>/src/runtime/ArcanistRuntime.php:858] #19 ArcanistRuntime::loadHardpoints(array, ArcanistHardpointRequestList) called at [<arcanist>/src/ref/symbol/ArcanistSymbolEngine.php:94] #20 ArcanistSymbolEngine::loadRefsForSymbols(ArcanistPasteSymbolRef, array) called at [<arcanist>/src/ref/symbol/ArcanistSymbolEngine.php:68] #21 ArcanistSymbolEngine::loadPastesForSymbols(array) called at [<arcanist>/src/ref/symbol/ArcanistSymbolEngine.php:63] #22 ArcanistSymbolEngine::loadPasteForSymbol(string) called at [<arcanist>/src/workflow/ArcanistPasteWorkflow.php:94] #23 ArcanistPasteWorkflow::runWorkflow(PhutilArgumentParser) called at [<arcanist>/src/workflow/ArcanistWorkflow.php:227] #24 ArcanistWorkflow::executeWorkflow(PhutilArgumentParser) called at [<arcanist>/src/toolset/ArcanistPhutilWorkflow.php:21] #25 ArcanistPhutilWorkflow::execute(PhutilArgumentParser) called at [<arcanist>/src/parser/argument/PhutilArgumentParser.php:492] #26 PhutilArgumentParser::parseWorkflowsFull(array) called at [<arcanist>/src/runtime/ArcanistRuntime.php:171] #27 ArcanistRuntime::executeCore(array) called at [<arcanist>/src/runtime/ArcanistRuntime.php:37] #28 ArcanistRuntime::execute(array) called at [<arcanist>/support/init/init-arcanist.php:6] #29 require_once(string) called at [<arcanist>/bin/arc:10] $ php -v PHP 8.4.4 (cli) (built: Feb 11 2025 15:36:20) (NTS) Copyright (c) The PHP Group Built by Homebrew Zend Engine v4.4.4, Copyright (c) Zend Technologies with Zend OPcache v8.4.4, Copyright (c), by Zend Technologies