The process has been signaled with signal '6'

What is this article about?

I had an annoying problem with composer on macosx while trying to install some packages, the error being thrown was not informative at all

[Symfony\Component\Process\Exception\RuntimeException]
The process has been signaled with signal '6' 

Solution

First, run the composer command verbose with

composer -vvv

Then you will see where it fails. In my case, it was failing right after:

Executing command (/Users/bekir/.composer): svn info --xml

So I tried svn info --xml alone to see what is really happening. The error this time was:

dyld: Library not loaded: /usr/local/lib/libsvn_client-1.0.dylib
Referenced from: /usr/local/bin/svn
Reason: image not found
Abort trap: 6

So obviously there was something wrong with the subversion installation. Since these packages are installed via homebrew, I did run

brew doctor

It produced:

Warning: You have unlinked kegs in your Cellar
Leaving kegs unlinked can lead to build-trouble and cause brews that depend on
those kegs to fail to run properly once built. Run `brew link` on these:
  docker
  boost
  composer
  subversion

When I linked the executables with brew link package_name it solved my problem.

brew link subversion
brew link composer
brew link boost