Adding a paragraph about updating multiple packages at once during an upgrade

Author: weaverryan

cookbook/upgrade/_update_all_packages.rst.inc

@@ -1,3 +1,6 @@
+Upgrading other Packages
+~~~~~~~~~~~~~~~~~~~~~~~~
+
 You may also want to upgrade the rest of your libraries. If you've done a
 good job with your `version constraints`_ in ``composer.json``, you can do
 this safely by running:

cookbook/upgrade/_update_dep_errors.rst.inc

@@ -0,0 +1,17 @@
+Dependency Errors
+~~~~~~~~~~~~~~~~~
+
+If you get a dependency error, it may just mean that you *also* need to upgrade
+that package too. For example, Symfony 2.7 requires a higher version of Twig,
+so just upgrading ``symfony/symfony`` alone may give you an error. In this
+case, try adding the package in question to the ``update`` statement:
+
+    $ composer update symfony/symfony twig/twig
+
+If this still doesn't work, your ``composer.json`` file may specify a version
+for a library that is not compatible with the newer Symfony version. In that
+case, updating that library to a newer version in ``composer.json`` may solve
+the issue.
+
+Or, you may have deeper issues where different libraries depend on conflicting
+versions of other libraries. Check your error message to debug.

cookbook/upgrade/major_version.rst

@@ -98,6 +98,8 @@ Next, use Composer to download new versions of the libraries:
 
     $ composer update symfony/symfony
 
+.. include:: /cookbook/upgrade/_update_dep_errors.rst.inc
+
 .. include:: /cookbook/upgrade/_update_all_packages.rst.inc
 
 .. _upgrade-major-symfony-after:

cookbook/upgrade/minor_version.rst

@@ -41,6 +41,8 @@ Next, use Composer to download new versions of the libraries:
 
     $ composer update symfony/symfony
 
+.. include:: /cookbook/upgrade/_update_dep_errors.rst.inc
+
 .. include:: /cookbook/upgrade/_update_all_packages.rst.inc
 
 .. _`upgrade-minor-symfony-code`: