在官方文档中说的第一步
$ composer require friendsofsymfony/user-bundle "~2.0"
这会给我这个错误
./composer.json has been updated
Loading composer repositories with package information
Updating dependencies (including require-dev)
Your requirements could not be resolved to an installable set of packages.
Problem 1
- Conclusion: don't install friendsofsymfony/user-bundle v2.1.2
- Conclusion: don't install friendsofsymfony/user-bundle v2.1.1
- Conclusion: don't install friendsofsymfony/user-bundle v2.1.0
- Conclusion: don't install friendsofsymfony/user-bundle v2.0.2
- Conclusion: don't install friendsofsymfony/user-bundle v2.0.1
- Conclusion: remove paragonie/random_compat v9.99.99
- Installation request for friendsofsymfony/user-bundle ~2.0 -> satisfiable by friendsofsymfony/user-bundle[v2.0.0, v2.0.1, v2.0.2, v2.1.0, v2.1.1, v2.1.2].
- Conclusion: don't install paragonie/random_compat v9.99.99
- friendsofsymfony/user-bundle v2.0.0 requires paragonie/random_compat ^1 || ^2 -> satisfiable by paragonie/random_compat[1.0.10, 1.0.2, 1.0.3, 1.0.4, 1.0.5, 1.0.6, 1.0.7, 1.0.8, 1.0.9, 1.1.0, 1.1.1, 1.1.2, 1.1.3, 1.1.4, 1.1.5, 1.1.6, v1.0.0, v1.0.1, v1.2.0, v1.2.1, v1.2.2, v1.2.3, v1.3.0, v1.3.1, v1.4.0, v1.4.1, v1.4.2, v1.4.3, v2.0.0, v2.0.1, v2.0.10, v2.0.11, v2.0.12, v2.0.13, v2.0.14, v2.0.15, v2.0.16, v2.0.17, v2.0.2, v2.0.3, v2.0.4, v2.0.5, v2.0.6, v2.0.7, v2.0.8, v2.0.9].
- Can only install one of: paragonie/random_compat[1.0.10, v9.99.99].
- Can only install one of: paragonie/random_compat[1.0.2, v9.99.99].
- Can only install one of: paragonie/random_compat[1.0.3, v9.99.99].
- Can only install one of: paragonie/random_compat[1.0.4, v9.99.99].
- Can only install one of: paragonie/random_compat[1.0.5, v9.99.99].
- Can only install one of: paragonie/random_compat[1.0.6, v9.99.99].
- Can only install one of: paragonie/random_compat[1.0.7, v9.99.99].
- Can only install one of: paragonie/random_compat[1.0.8, v9.99.99].
- Can only install one of: paragonie/random_compat[1.0.9, v9.99.99].
- Can only install one of: paragonie/random_compat[1.1.0, v9.99.99].
- Can only install one of: paragonie/random_compat[1.1.1, v9.99.99].
- Can only install one of: paragonie/random_compat[1.1.2, v9.99.99].
- Can only install one of: paragonie/random_compat[1.1.3, v9.99.99].
- Can only install one of: paragonie/random_compat[1.1.4, v9.99.99].
- Can only install one of: paragonie/random_compat[1.1.5, v9.99.99].
- Can only install one of: paragonie/random_compat[1.1.6, v9.99.99].
- Can only install one of: paragonie/random_compat[v1.0.0, v9.99.99].
- Can only install one of: paragonie/random_compat[v1.0.1, v9.99.99].
- Can only install one of: paragonie/random_compat[v1.2.0, v9.99.99].
- Can only install one of: paragonie/random_compat[v1.2.1, v9.99.99].
- Can only install one of: paragonie/random_compat[v1.2.2, v9.99.99].
- Can only install one of: paragonie/random_compat[v1.2.3, v9.99.99].
- Can only install one of: paragonie/random_compat[v1.3.0, v9.99.99].
- Can only install one of: paragonie/random_compat[v1.3.1, v9.99.99].
- Can only install one of: paragonie/random_compat[v1.4.0, v9.99.99].
- Can only install one of: paragonie/random_compat[v1.4.1, v9.99.99].
- Can only install one of: paragonie/random_compat[v1.4.2, v9.99.99].
- Can only install one of: paragonie/random_compat[v1.4.3, v9.99.99].
- Can only install one of: paragonie/random_compat[v2.0.0, v9.99.99].
- Can only install one of: paragonie/random_compat[v2.0.1, v9.99.99].
- Can only install one of: paragonie/random_compat[v2.0.10, v9.99.99].
- Can only install one of: paragonie/random_compat[v2.0.11, v9.99.99].
- Can only install one of: paragonie/random_compat[v2.0.12, v9.99.99].
- Can only install one of: paragonie/random_compat[v2.0.13, v9.99.99].
- Can only install one of: paragonie/random_compat[v2.0.14, v9.99.99].
- Can only install one of: paragonie/random_compat[v2.0.15, v9.99.99].
- Can only install one of: paragonie/random_compat[v2.0.16, v9.99.99].
- Can only install one of: paragonie/random_compat[v2.0.17, v9.99.99].
- Can only install one of: paragonie/random_compat[v2.0.2, v9.99.99].
- Can only install one of: paragonie/random_compat[v2.0.3, v9.99.99].
- Can only install one of: paragonie/random_compat[v2.0.4, v9.99.99].
- Can only install one of: paragonie/random_compat[v2.0.5, v9.99.99].
- Can only install one of: paragonie/random_compat[v2.0.6, v9.99.99].
- Can only install one of: paragonie/random_compat[v2.0.7, v9.99.99].
- Can only install one of: paragonie/random_compat[v2.0.8, v9.99.99].
- Can only install one of: paragonie/random_compat[v2.0.9, v9.99.99].
- Installation request for paragonie/random_compat (locked at v9.99.99) -> satisfiable by paragonie/random_compat[v9.99.99].
Installation failed, reverting ./composer.json to its original content.
这是我已安装的捆绑包的列表
behat/transliterator v1.2.0 String transliterator
cocur/slugify v3.1 Converts a string into a slug.
composer/ca-bundle 1.1.2 Lets you find a path to the system CA bundle, and includes a fallback to the Mozilla CA bundle.
doctrine/annotations v1.6.0 Docblock Annotations Parser
doctrine/cache v1.7.1 Caching library offering an object-oriented API for many cache backends
doctrine/collections v1.5.0 Collections Abstraction library
doctrine/common v2.9.0 Common Library for Doctrine projects
doctrine/dbal v2.8.0 Database Abstraction Layer
doctrine/doctrine-bundle 1.9.1 Symfony DoctrineBundle
doctrine/doctrine-cache-bundle 1.3.3 Symfony Bundle for Doctrine Cache
doctrine/event-manager v1.0.0 Doctrine Event Manager component
doctrine/inflector v1.3.0 Common String Manipulations with regard to casing and singular/plural rules.
doctrine/instantiator 1.1.0 A small, lightweight utility to instantiate objects in PHP without invoking their constructors
doctrine/lexer v1.0.1 Base library for a lexer that can be used in Top-Down, Recursive Descent Parsers.
doctrine/orm v2.6.2 Object-Relational-Mapper for PHP
doctrine/persistence v1.0.0 Doctrine Persistence abstractions.
doctrine/reflection v1.0.0 Doctrine Reflection component
fig/link-util 1.0.0 Common utility implementations for HTTP links
gedmo/doctrine-extensions v2.4.36 Doctrine2 behavioral extensions
incenteev/composer-parameter-handler v2.1.3 Composer script handling your ignored parameter file
jdorn/sql-formatter v1.2.17 a PHP SQL highlighting library
knplabs/knp-menu 2.3.0 An object oriented menu library
knplabs/knp-menu-bundle v2.2.1 This bundle provides an integration of the KnpMenu library
monolog/monolog 1.23.0 Sends your logs to files, sockets, inboxes, databases and various web services
paragonie/random_compat v9.99.99 PHP 5.x polyfill for random_bytes() and random_int() from PHP 7
psr/cache 1.0.1 Common interface for caching libraries
psr/container 1.0.0 Common Container Interface (PHP FIG PSR-11)
psr/link 1.0.0 Common interfaces for HTTP links
psr/log 1.0.2 Common interface for logging libraries
psr/simple-cache 1.0.1 Common interfaces for simple caching
sensio/distribution-bundle v5.0.22 Base bundle for Symfony Distributions
sensio/framework-extra-bundle v5.2.0 This bundle provides a way to configure your controllers with annotations
sensio/generator-bundle v3.1.7 This bundle generates code for you
sensiolabs/security-checker v4.1.8 A security checker for your composer.lock
sonata-project/admin-bundle 3.38.0 The missing Symfony Admin Generator
sonata-project/block-bundle 3.12.1 Symfony SonataBlockBundle
sonata-project/cache 2.0.1 Cache library
sonata-project/core-bundle 3.11.2 Symfony SonataCoreBundle
sonata-project/datagrid-bundle 2.3.1 Symfony SonataDatagridBundle
sonata-project/doctrine-orm-admin-bundle 3.6.1 Symfony Sonata / Integrate Doctrine ORM into the SonataAdminBundle
sonata-project/exporter 1.9.1 Lightweight Exporter library
sonata-project/intl-bundle 2.5.0 Symfony SonataIntlBundle
stof/doctrine-extensions-bundle v1.3.0 Integration of the gedmo/doctrine-extensions with Symfony2
swiftmailer/swiftmailer v5.4.12 Swiftmailer, free feature-rich PHP mailer
symfony/asset v4.1.3 Symfony Asset Component
symfony/monolog-bundle v3.3.0 Symfony MonologBundle
symfony/phpunit-bridge v3.4.14 Symfony PHPUnit Bridge
symfony/polyfill-apcu v1.9.0 Symfony polyfill backporting apcu_* functions to lower PHP versions
symfony/polyfill-ctype v1.9.0 Symfony polyfill for ctype functions
symfony/polyfill-intl-icu v1.9.0 Symfony polyfill for intl's ICU-related data and classes
symfony/polyfill-mbstring v1.9.0 Symfony polyfill for the Mbstring extension
symfony/polyfill-php56 v1.9.0 Symfony polyfill backporting some PHP 5.6+ features to lower PHP versions
symfony/polyfill-php70 v1.9.0 Symfony polyfill backporting some PHP 7.0+ features to lower PHP versions
symfony/polyfill-util v1.9.0 Symfony utilities for portability of PHP codes
symfony/security-acl v3.0.1 Symfony Security Component - ACL (Access Control List)
symfony/swiftmailer-bundle v2.6.7 Symfony SwiftmailerBundle
symfony/symfony v3.4.14 The Symfony PHP framework
twig/extensions v1.5.2 Common additional features for Twig that do not directly belong in core
twig/twig v2.5.0 Twig, the flexible, fast, and secure template language for PHP
答案 0 :(得分：7)
这是一个已知的错误，因为random_compat库由于某种原因最近被更新为一个奇怪的9.99.99版本，并且包中的依赖项被错误地声明。您可以做的是在自己的项目中明确要求^2.0版本。
运行：
composer require paragonie/random_compat ^2.0
或者您可以使用
修改composer.json。"require": {
...
"paragonie/random_compat": "^2.0",
...
},
然后，正常安装捆绑包。