[FEATURE] Linters and code analysis for TYPO3 projects

Example file for PHPStan usage

packages/example/Classes/PhpstanExample.php

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+<?php
+
+namespace Fh\Example;
+
+/**
+ * Example of PHPStan capabilities
+ * See https://medium.com/@ondrejmirtes/phpstan-2939cd0ad0e3 for further information
+ */
+class PhpstanExample
+{
+    /**
+     * Existence of classes used in instanceof, catch, typehints and other language constructs. PHP does not check this and just stays instead, rendering the surrounded code unused.
+     *
+     * @return string
+     */
+    public function checkInstanceof(): string
+    {
+        $fooBar = new \DateTime();
+        if ($fooBar instanceof \Fh\Example\NonExistingClassName) {
+            return 'Lorem';
+        } else {
+            return 'Ipsum';
+        }
+    }
+
+    /**
+     * Existence and accessibility of called methods and functions. It also checks the number of passed arguments.
+     *
+     * @return void
+     */
+    public function checkFunctionsAndNumberOfArguments(): void
+    {
+        $this->anotherMethod('Foo', 'Bar', 'Lorem');
+    }
+
+    /**
+     * @param string $foo
+     * @param string $bar
+     * @return string
+     */
+    protected function anotherMethod(string $foo, string $bar): string
+    {
+        return 'Foo: ' . $foo . ', Bar: ' . $bar;
+    }
+
+    /**
+     * Whether a method returns the same type it declares to return.
+     *
+     * @return integer
+     */
+    public function checkReturnType(): int
+    {
+        return 'Lorem';
+    }
+
+    /**
+     * Existence and visibility of accessed properties. It will also point out if a different type from the declared one is assigned to the property.
+     *
+     * @return void
+     */
+    public function checkTypeOfDeclaredProperties(): void
+    {
+        $this->anotherMethod('Foo', false);
+    }
+
+    /**
+     * Correct number of parameters passed to sprintf/printf calls based on format strings.
+     *
+     * @return void
+     */
+    public function checkVariableScopes(): void
+    {
+        $foo = 'Foo';
+        $exampleFunction = function (): string {
+            return $foo;
+        };
+    }
+
+    /**
+     * Useless casting like (string) ‘foo’ and strict comparisons (=== and !==) with different types as operands which always result in false.
+     *
+     * @return boolean
+     */
+    public function checkUselessTypeComparison(): bool
+    {
+        $lorem = 'Lorem';
+        return ($lorem === 1);
+    }
+
+    /**
+     * @return int[]
+     */
+    public function checkTypeOfArrayVariables(): array
+    {
+        return [
+            'Foo',
+            'Bar',
+        ];
+    }
+
+    /**
+     * @return string
+     */
+    public function checkUnreachableStatement(): string
+    {
+        $lorem = 'Lorem';
+        return $lorem;
+
+        $ipsum = 'Ipsum';
+    }
+}

packages/example/composer.json

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+{
+	"name": "fh/example",
+	"description": "Example",
+	"type": "typo3-cms-extension",
+	"authors": [
+		{
+			"name": "Felix Heller",
+			"email": "felix.heller@web.de"
+		}
+	],
+	"autoload": {
+		"psr-4": {
+			"Fh\\Example\\": "Classes"
+		}
+	}
+}