composer/composer — pull request #1341 by beberlei (2012-11-19 09:33:33+00:00)
Title: Fallback to PHP early if proc_open not allowed.

This happend to me on Azure Websites where all shell functions are deactivated. Using

composer install --prefer-dist

I can circumvent the usage of process for installing Git repositories, but Filesystem#removeDirectory() was left over. I built an early exit solution using PHP to solve the problem.