🐞 fix: Error cleanup, add test harness

vendor/staabm/side-effects-detector/lib/SideEffect.php

@@ -0,0 +1,42 @@
+<?php
+
+namespace staabm\SideEffectsDetector;
+
+/**
+ * @api
+ */
+final class SideEffect {
+    /**
+     * die, exit, throw.
+     */
+    const PROCESS_EXIT = 'process_exit';
+
+    /**
+     * class definition, func definition, include, require, global var, unset, goto
+     */
+    const SCOPE_POLLUTION = 'scope_pollution';
+
+    /**
+     * fwrite, unlink...
+     */
+    const INPUT_OUTPUT = 'input_output';
+
+    /**
+     * echo, print.
+     */
+    const STANDARD_OUTPUT = 'standard_output';
+
+    /**
+     * code for sure has side-effects, we don't have enough information to classify it.
+     */
+    const UNKNOWN_CLASS = 'unknown_class';
+
+    /**
+     * code might have side-effects, but we can't tell for sure.
+     */
+    const MAYBE = 'maybe_has_side_effects';
+
+    private function __construct() {
+        // nothing todo
+    }
+}