Explain process

Author: Bellangelo

README.md

@@ -1 +1,31 @@
-# phpstan-require-file-exists
+# phpstan-require-file-exists
+Weirdly enough, PHPStan does not check if a file exists when used in a
+`require` or `include` statement. This is a PHPStan rule that tries to do
+exactly that.
+
+## Installation
+```bash
+composer require --dev bellangelo/phpstan-require-file-exists
+```
+
+## Configuration
+Add the following to your `phpstan.neon`:
+```neon
+services:
+    -
+        class: Bellangelo\PHPStanRequireFileExists\RequireFileExistsRule
+        arguments:
+           - @reflectionProvider
+        tags: [phpstan.rules.rule]
+```
+
+You can find a `phpstan.neon` example in the `tests` directory, here: [tests/phpstan.neon](tests/phpstan-testing.neon).
+
+## Supported cases
+- `require 'file.php';` - might not find it since the path is relative.
+- `require __DIR__ . '/file.php';` - can find it, if it exists.
+- `require __DIR__ . '/' . MyClass::MY_CONST;` - can find it if the const has the correct value from the start.
+
+## Unsupported cases
+- `require $file;` - won't throw an error since it cannot read variables.
+- `require (new MyClass())->file;` - won't throw an error since it cannot read class properties.