Merge branch '3.4'

* 3.4:
  [#8195] fix requirement checker binary
  Simplified the requirements article
  [#6030] Simplifying and showing code
  Clearify behaviour of Blank and NotBlank validator
  [#5838] Tweaking comment - the phpdoc policy is not concrete
  Update standards to match actual practices
  Updated the Requirements article for Symfony 3.4
  Updated the requirements article for Smyfony 3.3
  Updated the Requirements article for Symfony 3.2
  Updated the Requirements article for Symfony 2.8

Author: xabbuh

contributing/code/standards.rst

@@ -226,7 +226,8 @@ Service Naming Conventions
 Documentation
 -------------
 
-* Add PHPDoc blocks for all classes, methods, and functions;
+* Add PHPDoc blocks for all classes, methods, and functions (though you may
+  be asked to remove PHPDoc that do not add value);
 
 * Group annotations together so that annotations of the same type immediately
   follow each other, and annotations of a different type are separated by a

reference/constraints/Blank.rst

@@ -1,10 +1,18 @@
 Blank
 =====
 
-Validates that a value is blank, defined as equal to a blank string or equal
-to ``null``. To force that a value strictly be equal to ``null``, see the
-:doc:`/reference/constraints/IsNull` constraint. To force that a value is
-*not* blank, see :doc:`/reference/constraints/NotBlank`.
+Validates that a value is blank - meaning equal to an empty string or ``null``::
+
+    if ('' !== $value && null !== $value) {
+        // validation will fail
+    }
+
+To force that a value strictly be equal to ``null``, see the
+:doc:`/reference/constraints/IsNull` constraint.
+
+
+To force that a value is *not* blank, see :doc:`/reference/constraints/NotBlank`.
+But be careful as ``NotBlank`` is *not* strictly the opposite of ``Blank``.
 
 +----------------+---------------------------------------------------------------------+
 | Applies to     | :ref:`property or method <validation-property-target>`              |

reference/constraints/NotBlank.rst

@@ -1,9 +1,14 @@
 NotBlank
 ========
 
-Validates that a value is not blank, defined as not strictly ``false``,
-not equal to a blank string and also not equal to ``null``. To force that
-a value is simply not equal to ``null``, see the
+Validates that a value is not blank - meaning not equal to a blank string,
+a blank array or ``null``::
+
+    if (false === $value || (empty($value) && '0' != $value)) {
+        // validation will fail
+    }
+
+To force that a value is simply not equal to ``null``, see the
 :doc:`/reference/constraints/NotNull` constraint.
 
 +----------------+------------------------------------------------------------------------+

reference/requirements.rst

@@ -6,50 +6,29 @@
 Requirements for Running Symfony
 ================================
 
-To run Symfony, your system needs to adhere to a list of requirements. You
-can easily see if your system passes all requirements by running the
-``web/config.php`` in your Symfony distribution. Since the CLI often uses
-a different ``php.ini`` configuration file, it's also a good idea to check
-your requirements from the command line via:
+Symfony 3.4 requires **PHP 5.5.9** or higher to run, in addition to other minor
+requirements. To make things simple, Symfony provides a tool to quickly check if
+your system meets all those requirements.
 
-.. code-block:: terminal
-
-    $ php bin/symfony_requirements
-
-Below is the list of required and optional requirements.
+Beware that PHP can define a different configuration for the command console and
+the web server, so you need to check requirements in both environments.
 
-Required
---------
+Checking Requirements for the Web Server
+----------------------------------------
 
-* PHP needs to be a minimum version of PHP 5.5.9
-* `JSON extension`_ needs to be enabled
-* `ctype extension`_ needs to be enabled
-* Your ``php.ini`` needs to have the ``date.timezone`` setting
+Symfony includes a ``config.php`` file in the ``web/`` directory of your project.
+Open that file with your browser to check the requirements.
 
-Optional
---------
+Once you've fixed all the reported issues, delete the ``web/config.php`` file
+to avoid leaking internal information about your application to visitors.
 
-* You need to have the PHP-XML module installed
-* You need to have at least version 2.6.21 of libxml
-* PHP tokenizer needs to be enabled
-* mbstring functions need to be enabled
-* iconv needs to be enabled
-* POSIX needs to be enabled (only on \*nix)
-* Intl needs to be installed with ICU 4+
-* APC 3.0.17+ (or another opcode cache needs to be installed)
-* ``php.ini`` recommended settings
+Checking Requirements for the Command Console
+---------------------------------------------
 
-  * ``short_open_tag = Off``
-  * ``magic_quotes_gpc = Off``
-  * ``register_globals = Off``
-  * ``session.auto_start = Off``
+Open your console or terminal, enter in your project directory, execute this
+command and fix the reported issues:
 
-Doctrine
---------
-
-If you want to use Doctrine, you will need to have PDO installed. Additionally,
-you need to have the PDO driver installed for the database server you want
-to use.
+.. code-block:: terminal
 
-.. _`JSON extension`: https://php.net/manual/book.json.php
-.. _`ctype extension`: https://php.net/manual/book.ctype.php
+    $ cd my-project/
+    $ php bin/symfony_requirements