[MINOR] Drop support for symfony < 4.2

.travis.yml

@@ -40,9 +40,6 @@ matrix:
     - stage: test
       php: 7.2
       env: COMPOSER_FLAGS="--prefer-lowest"
-    - stage: test
-      php: 7.3
-      env: SYMFONY_VERSION=3.4.*
     - stage: test
       php: 7.3
       env: SYMFONY_VERSION=4.2.*

composer.json

@@ -31,15 +31,15 @@
         "psr/http-message": "^1.0",
         "sonata-project/block-bundle": "^3.18",
         "sonata-project/core-bundle": "^3.17",
-        "symfony/config": "^3.4 || ^4.2",
-        "symfony/dependency-injection": "^3.4 || ^4.2",
-        "symfony/expression-language": "^3.4 || ^4.2",
-        "symfony/form": "^3.4 || ^4.2",
-        "symfony/framework-bundle": "^3.4 || ^4.2",
-        "symfony/http-foundation": "^3.4 || ^4.2",
-        "symfony/http-kernel": "^3.4 || ^4.2",
-        "symfony/options-resolver": "^3.4 || ^4.2",
-        "symfony/twig-bundle": "^3.4 || ^4.2"
+        "symfony/config": "^4.2",
+        "symfony/dependency-injection": "^4.2",
+        "symfony/expression-language": "^4.2",
+        "symfony/form": "^4.2",
+        "symfony/framework-bundle": "^4.2",
+        "symfony/http-foundation": "^4.2",
+        "symfony/http-kernel": "^4.2",
+        "symfony/options-resolver": "^4.2",
+        "symfony/twig-bundle": "^4.2"
     },
     "require-dev": {
         "bamarni/composer-bin-plugin": "^1.3",

phpstan.neon.dist

@@ -21,13 +21,3 @@ parameters:
             message: "#^Offset 'host' does not exist on array\\(\\)\\|array\\('scheme' \\=\\> string, 'host' \\=\\> string, 'port' \\=\\> int, 'user' \\=\\> string, 'pass' \\=\\> string, 'path' \\=\\> string, 'query' \\=\\> string, 'fragment' \\=\\> string\\)\\.$#"
             count: 1
             path: src/Backend/PsrBackend.php
-
-        -
-            message: "#^Call to function method_exists\\(\\) with 'Symfony\\\\\\\\Component…' and 'getRootNode' will always evaluate to false\\.$#"
-            count: 1
-            path: src/DependencyInjection/Configuration.php
-
-        -
-            message: "#^Call to an undefined method Symfony\\\\Component\\\\Config\\\\Definition\\\\Builder\\\\TreeBuilder\\:\\:root\\(\\)\\.$#"
-            count: 1
-            path: src/DependencyInjection/Configuration.php

src/DependencyInjection/Configuration.php

@@ -22,12 +22,8 @@ public function getConfigTreeBuilder()
     {
         $treeBuilder = new TreeBuilder('core23_shariff');
 
-        // Keep compatibility with symfony/config < 4.2
-        if (!method_exists(TreeBuilder::class, 'getRootNode')) {
-            $rootNode = $treeBuilder->root('core23_shariff');
-        } else {
-            $rootNode = $treeBuilder->getRootNode();
-        }
+        $rootNode = $treeBuilder->getRootNode();
+
         \assert($rootNode instanceof ArrayNodeDefinition);
 
         $this->addAliases($rootNode);