Merge branch '3.4' into 4.0

* 3.4:
  [HttpKernel] Make ServiceValueResolver work if controller namespace starts with a backslash in routing
  Add d-block to bootstrap 4 alerts
  [Console] Don't go past exact matches when autocompleting
  [DI] Improve error message for non-autowirable scalar argument
  Disable autoloader call on interface_exists check
  [Validator] Fix LazyLoadingMetadataFactory with PSR6Cache for non classname if tested values isn't an existing class
  [HttpKernel] Dont create mock cookie for new sessions in tests

Author: nicolas-grekas

Resources/views/Form/bootstrap_4_layout.html.twig

@@ -267,7 +267,7 @@
 
 {% block form_errors -%}
     {%- if errors|length > 0 -%}
-        <span class="{% if form is not rootform %}invalid-feedback d-block{% else %}alert alert-danger{% endif %}">
+        <span class="{% if form is not rootform %}invalid-feedback{% else %}alert alert-danger{% endif %} d-block">
             {%- for error in errors -%}
                 <span class="mb-0 d-block">
                     <span class="initialism form-error-icon badge badge-danger">{{ 'Error'|trans({}, 'validators') }}</span> <span class="form-error-message">{{ error.message }}</span>

composer.json

@@ -23,7 +23,7 @@
         "symfony/asset": "~3.4|~4.0",
         "symfony/dependency-injection": "~3.4|~4.0",
         "symfony/finder": "~3.4|~4.0",
-        "symfony/form": "^3.4.7|^4.0.7",
+        "symfony/form": "^3.4.9|^4.0.9",
         "symfony/http-foundation": "~3.4|~4.0",
         "symfony/http-kernel": "~3.4|~4.0",
         "symfony/polyfill-intl-icu": "~1.0",
@@ -41,7 +41,7 @@
         "symfony/workflow": "~3.4|~4.0"
     },
     "conflict": {
-        "symfony/form": "<3.4.7|<4.0.7,>=4.0",
+        "symfony/form": "<3.4.9|<4.0.9,>=4.0",
         "symfony/console": "<3.4"
     },
     "suggest": {