Merge branch '4.0' into 4.1

* 4.0:
  Improved the section about overriding bundle services
  Link to the env vars article from the Best Practices
  Added a caution note about race conditions in EntityType
  Minor reword of deployment article when using Flex
  Mention how to inject a specific Monolog service

Author: javiereguiluz

best_practices/configuration.rst

@@ -17,9 +17,9 @@ application behavior.
 
 .. best-practice::
 
-    Define the infrastructure-related configuration options as environment
-    variables. During development, use the ``.env`` file at the root of your
-    project to set these.
+    Define the infrastructure-related configuration options as
+    :doc:`environment variables </configuration/external_parameters>`. During
+    development, use the ``.env`` file at the root of your project to set these.
 
 By default, Symfony adds these types of options to the ``.env`` file when
 installing new dependencies in the app:

bundles/override.rst

@@ -66,31 +66,12 @@ before the bundle one).
 Services & Configuration
 ------------------------
 
-If you want to modify service definitions of another bundle, you can use a compiler
-pass to change the class of the service or to modify method calls. In the following
-example, the implementing class for the ``original-service-id`` is changed to
-``App\YourService``:
-
-.. code-block:: diff
-
-    // src/Kernel.php
-    namespace App;
-
-    // ...
-    + use App\Service\YourService;
-    + use Symfony\Component\DependencyInjection\ContainerBuilder;
-    + use Symfony\Component\DependencyInjection\Compiler\CompilerPassInterface;
-
-    class Kernel extends BaseKernel implements CompilerPassInterface
-    {
-    +     public function process(ContainerBuilder $container)
-    +     {
-    +         $definition = $container->findDefinition('original-service-id');
-    +         $definition->setClass(YourService::class);
-    +     }
-    }
-
-For more information on compiler passes, see :doc:`/service_container/compiler_passes`.
+If you want to modify the services created by a bundle, you can use
+:doc:`service decoration </service_container/service_decoration>`.
+
+If you want to do more advanced manipulations, like removing services created by
+other bundles, you must work with :doc:`service definitions </service_container/definitions>`
+inside a :doc:`compiler pass </service_container/compiler_passes>`.
 
 Entities & Entity Mapping
 -------------------------

deployment.rst

@@ -132,10 +132,9 @@ How you set environment variables, depends on your setup: they can be set at the
 command line, in your Nginx configuration, or via other methods provided by your
 hosting service.
 
-At the very least you need to define the ``SYMFONY_ENV=prod`` (or
-``APP_ENV=prod`` if you're using :doc:`Symfony Flex </setup/flex>`) to run the
-application in ``prod`` mode, but depending on your application you may need to
-define other env vars too.
+At the very least you need to define the ``APP_ENV=prod`` environment variable
+to run the application in ``prod`` mode, but depending on your application you
+may need to define other env vars too.
 
 C) Install/Update your Vendors
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

frontend/encore/simple-example.rst

@@ -202,4 +202,4 @@ If those entries include CSS/Sass files (e.g. ``homepage.js`` requires
 Keep Going!
 -----------
 
-Go back to the :ref:`Encore Top List <encore-toc>` to learn more and add new features.
+Go back to the :ref:`List of Encore Articles <encore-toc>` to learn more and add new features.

logging/channels_handlers.rst

@@ -168,5 +168,7 @@ You can also configure additional channels without the need to tag your services
             ),
         ));
 
-With this, you can now send log messages to the ``foo`` channel by using
-the automatically registered logger service ``monolog.logger.foo``.
+Symfony automatically registers one service per channel (in this example, the
+channel ``foo`` creates a service called ``monolog.logger.foo``). In order to
+inject this service into others, you must update the service configuration to
+:ref:`choose the specific service to inject <services-wire-specific-service>`.

reference/constraints/UniqueEntity.rst

@@ -109,6 +109,13 @@ between all of the constraints in your user table:
             }
         }
 
+.. caution::
+
+    This constraint doesn't provide any protection against `race conditions`_.
+    They may occur when another entity is persisted by an external process after
+    this validation has passed and before this entity is actually persisted in
+    the database.
+
 Options
 -------
 
@@ -280,3 +287,5 @@ If set to ``false``, only one ``null`` value is allowed - if a second entity
 also has a ``null`` value, validation would fail.
 
 .. include:: /reference/constraints/_payload-option.rst.inc
+
+.. _`race conditions`: https://en.wikipedia.org/wiki/Race_condition

service_container/compiler_passes.rst

@@ -5,10 +5,10 @@
 How to Work with Compiler Passes
 ================================
 
-Compiler passes give you an opportunity to manipulate other service
-definitions that have been registered with the service container. You
-can read about how to create them in the components section
-":ref:`components-di-separate-compiler-passes`".
+Compiler passes give you an opportunity to manipulate other
+:doc:`service definitions </service_container/definitions>` that have been
+registered with the service container. You can read about how to create them in
+the components section ":ref:`components-di-separate-compiler-passes`".
 
 Compiler passes are registered in the ``build()`` method of the application kernel::
 
@@ -89,8 +89,8 @@ method in the extension)::
         }
     }
 
-If you are using custom service tags in a bundle then by convention, tag names
-consist of the name of the bundle (lowercase, underscores as separators),
-followed by a dot, and finally the "real" name. For example, if you want to
-introduce some sort of "transport" tag in your AcmeMailerBundle, you should call
-it ``acme_mailer.transport``.
+If you are using custom :doc:`service tags </service_container/tags>` in a
+bundle then by convention, tag names consist of the name of the bundle
+(lowercase, underscores as separators), followed by a dot, and finally the
+"real" name. For example, if you want to introduce some sort of "transport" tag
+in your AcmeMailerBundle, you should call it ``acme_mailer.transport``.