参考地址：https://cmsdk.com/php/installing-symfony-project-with-php-7-3-version.html
Tryng to install (and after updating composer):
composer create-project symfony-cmf/sandbox cmf-sandbox
I have those errors:
Installing symfony-cmf/sandbox (2.0.0)
- Installing symfony-cmf/sandbox (2.0.0): Loading from cache
Created project in cmf-sandbox
Loading composer repositories with package information
Installing dependencies (including require-dev) from lock file
Your requirements could not be resolved to an installable set of packages.
Problem 1
- Installation request for phpcr/phpcr-utils 1.3.0 -> satisfiable by phpcr/phpcr-utils[1.3.0].
- phpcr/phpcr-utils 1.3.0 requires php ^5.6|7.0.x|7.1.x -> your PHP version (7.3.0) does not satisfy that requirement.
Problem 2
- phpcr/phpcr-utils 1.3.0 requires php ^5.6|7.0.x|7.1.x -> your PHP version (7.3.0) does not satisfy that requirement.
- doctrine/phpcr-odm 1.4.2 requires phpcr/phpcr-utils ^1.2.8 -> satisfiable by phpcr/phpcr-utils[1.3.0].
- Installation request for doctrine/phpcr-odm 1.4.2 -> satisfiable by doctrine/phpcr-odm[1.4.2].
Edit: Continuing the recommendation of Timo, I was able to install the project by executing the following:
composer create-project --ignore-platform-reqs symfony-cmf/sandbox cmf-sandbox
but I have obtained the following errors:
PHP Fatal error: Uncaught Symfony\Component\Debug\Exception\ContextErrorException: Warning: count(): Parameter must be an array or an object that implements Countable in /srv/http/symfony/cmf-sandbox/vendor/symfony-cmf/routing/src/ChainRouter.php:101
Stack trace:
#0 /srv/http/symfony/cmf-sandbox/vendor/symfony-cmf/routing/src/ChainRouter.php(308): Symfony\Cmf\Component\Routing\ChainRouter->all()
#1 /srv/http/symfony/cmf-sandbox/var/cache/dev/appDevDebugProjectContainer.php(1670): Symfony\Cmf\Component\Routing\ChainRouter->setContext(Object(Symfony\Component\Routing\RequestContext))
#2 /srv/http/symfony/cmf-sandbox/vendor/symfony/symfony/src/Symfony/Component/DependencyInjection/Container.php(335): appDevDebugProjectContainer->getCmfRouting_RouterService()
#3 /srv/http/symfony/cmf-sandbox/var/cache/dev/appDevDebugProjectContainer.php(4955): Symfony\Component\DependencyInjection\Container->get('cmf_routing.rou...')
#4 /srv/http/symfony/cmf-sandbox/vendor/symfony/symfony/src/Symfony/Component/DependencyInjection/Container.php(33 in /srv/http/symfony/cmf-sandbox/vendor/symfony-cmf/routing/src/ChainRouter.php on line 101
The project uses a Symfony version 3 structure and may have some incompatibility with PHP 7.3 (as Timo says).
Answer 1
You can tell Composer to ignore the PHP version requirements by adding --ignore-platform-reqs to the composer create-project command.
Else, you'll probably have to wait until the dependencies of symfony-cmf/sandbox get bumped to a later version.