[HttpFoundation] getClientIp is fixed.

The getClientIp now returns ip of the earliest server in a proxy chain when all the servers in the chain are trusted proxies. Before this patch the getClientIp used to return null at such condition.
Some appropriate tests are added.
[HttpFoundation] fixed the creation of sub-requests under some circumstances for IIS
Update PhpEngine.php

just a minor phpdoc fix
merged branch janschoenherr/patch-5 (PR #7600)

This PR was submitted for the 2.2 branch but it was merged into the 2.1 branch instead (closes #7600).

Discussion
----------

[Templating] Update PhpEngine.php

| Q             | A
| ------------- | ---
| Bug fix?      | no
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets |
| License       | MIT
| Doc PR        |

just a minor phpdoc fix

Commits
-------

171b41f Update PhpEngine.php
merged branch denvned/getClientIp-fix (PR #7472)

This PR was merged into the 2.1 branch.

Discussion
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[HttpFoundation] getClientIp is fixed.

| Q             | A
| ------------- | ---
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | n/a
| License       | MIT
| Doc PR        | no

The getClientIp now returns ip of the earliest server in a proxy chain when all the servers in the chain are trusted proxies. Before this patch the getClientIp used to return null at such condition.
Some appropriate tests are added.

Commits
-------

c4da2d9 [HttpFoundation] getClientIp is fixed.
[Form] DateTimeToRfc3339Transformer use proper transformation exteption in reverse transformation
[HttpFoundation] Fixed bug in key searching for NamespacedAttributeBag

Fixed a bug in NamespacedAttributeBag causing a result to be falsely found when
the last key of the attribute matched the last of the queried name regardless of
if the key did not exist in the search.
Added Tests to demonstrate the issue and resolved by setting keys to null when
iterating through query and returning proper responses in the case that the
given array does in fact not exist.

* Updated Syntax of null checks
* Fixing missing else case for if statement in write context
The /e modifier for preg_replace() is deprecated in PHP 5.5; replace with preg_replace_callback()
merged branch Tatsh/master (PR #7624)

This PR was submitted for the master branch but it was merged into the 2.1 branch instead (closes #7624).

Discussion
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[FrameworkBundle] RegisterKernelListenersPass: Removed and replaced use of deprecated preg_match() /e modifier with regards to PHP 5.5

More information: https://wiki.php.net/rfc/remove_preg_replace_eval_modifier

As of beta 2 of PHP 5.5, the above is implemented. Attempting to run the current version of Symfony FrameworkBundle (or 2.1) will cause an `ErrorException`.

| Q             | A
| ------------- | ---
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets |
| License       | MIT
| Doc PR        |

Commits
-------

c1e98b9 The /e modifier for preg_replace() is deprecated in PHP 5.5; replace with preg_replace_callback()
[Routing][XML Loader] Add a possibility to set a default value to null
merged branch kibao/datetime-rfc3339-transformer (PR #7618)

This PR was merged into the 2.1 branch.

Discussion
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[Form] DateTimeToRfc3339Transformer use proper transformation exteption in reverse transformation

Handle _Exception_ throwed by DateTime constructor if an invalid date is passed.
Then throws proper transformation exception.

| Q             | A
| ------------- | ---
| Bug fix?      | no
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | n/a
| License       | MIT
| Doc PR        | n/a

Commits
-------

7fc429f [Form] DateTimeToRfc3339Transformer use proper transformation exteption in reverse transformation
merged branch Aitboudad/ticket__7335 (PR #7635)

This PR was merged into the 2.1 branch.

Discussion
----------

[Routing][XML Loader] Add a possibility to set a default value to null

| Q             | A
| ------------- | ---
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | https://github.com/symfony/symfony/issues/7335
| License       | MIT

Example:

    <route id="acme_user_show" pattern="/{id}">
        <default key="_controller">AcmeUserBundle:User:show</default>
        <default key="id" xsi:nil="true" />
    </route>

Commits
-------

94a9cdc [Routing][XML Loader] Add a possibility to set a default value to null
merged branch MaxVandervelde/fix/namespaced-parameter-issue (PR #7586)

This PR was merged into the 2.1 branch.

Discussion
----------

[HttpFoundation] Fixed bug in key searching for NamespacedAttributeBag

| Q             | A
| ------------- | ---
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | #7564
| License       | MIT
| Doc PR        | N/A

Fixed a bug in NamespacedAttributeBag causing a result to be falsely found when
the last key of the attribute matched the last of the queried name regardless of
if the key did not exist in the search.
Added Tests to demonstrate the issue and resolved by setting keys to null when
iterating through query and returning proper responses in the case that the
given array does in fact not exist.

Commits
-------

0f0c29c [HttpFoundation] Fixed bug in key searching for NamespacedAttributeBag
[Yaml] fixed handling an empty value
[Yaml] improved boolean naming ($notEOF -> !$EOF)
merged branch pvolok/fix-7274 (PR #7641)

This PR was merged into the 2.1 branch.

Discussion
----------

[2.2][Yaml] Fixed resolving blank values

| Q             | A
| ------------- | ---
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | #7274
| License       | MIT
| Doc PR        | -

Also, Seldaek suggested to rename the $notEOF variable.

Commits
-------

fb686d8 [Yaml] improved boolean naming ($notEOF -> !$EOF)
047212a [Yaml] fixed handling an empty value
[HttpFoundation] do not use server variable PATH_INFO because it is already decoded and thus symfony is fragile to double encoding of the path
merged branch Tobion/apache-pathinfo (PR #7656)

This PR was merged into the 2.1 branch.

Discussion
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[HttpFoundation] do not use server variable PATH_INFO

because it is already decoded (see http://www.ietf.org/rfc/rfc3875) and thus symfony is fragile to double encoding of the path. This is not really a security issue (in contrast to a [previous problem](http://symfony.com/blog/security-release-symfony-2-0-20-and-2-1-5-released)) but when using the apacherequest, one could access pages with double encoded characters although the path should not match.

BC break: no
tests pass: yes

Commits
-------

d552e4c [HttpFoundation] do not use server variable PATH_INFO because it is already decoded and thus symfony is fragile to double encoding of the path
Disabled APC on Travis for PHP 5.5+ as it is not available
merged branch stof/fix_travis_5_5 (PR #7663)

This PR was merged into the 2.1 branch.

Discussion
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Disabled APC on Travis for PHP 5.5+ as it is not available

As APC is not available, PHP triggers a warning when trying to load the extension, which lead to many test failures.

Commits
-------

6084176 Disabled APC on Travis for PHP 5.5+ as it is not available