下面由composer教程欄目給大家介紹關于Composer常見錯誤及其解決辦法，希望對需要的朋友有所幫助！

Composer常見錯誤解決方案

執(zhí)行composer install遇到錯誤：Your requirements could not be resolved to an installable set of packages. 這是因為不匹配composer.json要求的版本。

完整錯誤如下：

vagrant@homestead:/usr/share/nginx/html/laravel-blog$ sudocomposerinstall Loadingcomposerrepositorieswithpackage information Installingdependencies (includingrequire-dev) fromlockfile Yourrequirementscouldnot beresolvedto aninstallablesetofpackages.      Problem 1     - Installationrequestfor doctrine/instantiator 1.0.3 -> satisfiablebydoctrine/instantiator[1.0.3].     - doctrine/instantiator 1.0.3 requiresphp ~5.3 -> yourPHPversion (7.0.3) doesnot satisfythatrequirement.   Problem 2     - doctrine/instantiator 1.0.3 requiresphp ~5.3 -> yourPHPversion (7.0.3) doesnot satisfythatrequirement.     - phpunit/phpunit-mock-objects 2.3.0 requiresdoctrine/instantiator ~1.0,>=1.0.1 -> satisfiablebydoctrine/instantiator[1.0.3].     - Installationrequestfor phpunit/phpunit-mock-objects 2.3.0 -> satisfiablebyphpunit/phpunit-mock-objects[2.3.0].

提示我的PHP 7版本太高，不符合composer.json需要的版本，但是在PHP 7下應該也是可以運行的，composer可以設置忽略版本匹配，命令是：

composerinstall --ignore-platform-reqs

或者

composerupdate --ignore-platform-reqs

再次執(zhí)行composer命令可以正常安裝包了。

如果提示警告：

Cannotcreatecachedirectory /home/vagrant/.composer/cache/repo/https---packagist.org/, or directoryis not writable. Proceedingwithoutcache   Cannotcreatecachedirectory /home/vagrant/.composer/cache/files/, or directoryis not writable. Proceedingwithoutcache

這是在虛擬機中執(zhí)行composer，提示這個目錄沒有可寫權限，composer無法緩存下載的包，這樣就每次都得重新下載，把目錄改成可寫可讀即可。

sudo chmod -R 777 /home/vagrant/.composer/cache/files/

另外，在虛擬機中也設置composer為國內鏡像，不然下載速度慢的要死，執(zhí)行：

composerconfig -g repo.packagistcomposerhttps://packagist.phpcomposer.com