Merge pull request #506 from igorw/lockfile-lib-docs

[docs] clarify lock file insignificance for libs

doc/01-basic-usage.md

@@ -98,7 +98,7 @@ After installing the dependencies, Composer writes the list of the exact
 versions it installed into a `composer.lock` file. This locks the project
 to those specific versions.
 
-**Commit your project's `composer.lock` (along with `composer.json`) into version control.**
+**Commit your application's `composer.lock` (along with `composer.json`) into version control.**
 
 This is important because the `install` command checks if a lock file is present,
 and if it is, it downloads the versions specified there (regardless of what `composer.json`
@@ -115,6 +115,9 @@ the lock file with the new version.
 
     $ php composer.phar update
 
+> **Note:** For libraries it is not necessarily recommended to commit the lock file,
+> see also: [Libraries - Lock file](02-libraries.md#lock-file).
+
 ## Packagist
 
 [Packagist](http://packagist.org/) is the main Composer repository. A Composer

doc/02-libraries.md

@@ -78,15 +78,13 @@ See [Repositories](05-repositories.md) for more information.
 
 ## Lock file
 
-For projects it is recommended to commit the `composer.lock` file into version
-control. For libraries this is not the case. You do not want your library to
-be tied to exact versions of the dependencies. It should work with any
-compatible version, so make sure you specify your version constraints so that
-they include all compatible versions.
+For your library you may commit the `composer.lock` file if you want to. This
+can help your team to always test against the same dependency versions.
+However, this lock file will not have any effect on other projects that depend
+on it. It only has an effect on the main project.
 
-**Do not commit your library's `composer.lock` into version control.**
-
-If you are using git, add it to the `.gitignore`.
+If you do not want to commit the lock file and you are using git, add it to
+the `.gitignore`.
 
 ## Publishing to a VCS