title: composer.lock: how does it work?
body: <p>I'm trying to understand this part: <a href="http://getcomposer.org/doc/02-libraries.md#lock-file">http://getcomposer.org/doc/02-libraries.md#lock-file</a></p>
  
  <blockquote>
    <p>this lock file will not have any effect on other projects that depend on it. It only has an effect on the main project"</p>
  </blockquote>
  
  <p>Does that mean that if project P depends on library A, and library A depends on library B v1.3, project P won't care about the version of library B, and will possibly install B 1.4 instead? What's the point then?</p>
  
  <p>Or does it mean the opposite, as one would expect from a dependency manager?</p>