--- /dev/null
+<?php
+
+/*
+ * This file is part of Psy Shell.
+ *
+ * (c) 2012-2017 Justin Hileman
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Psy\CodeCleaner;
+
+use PhpParser\Node;
+use PhpParser\Node\Expr;
+use PhpParser\Node\Expr\FuncCall;
+use PhpParser\Node\Expr\Variable;
+use PhpParser\Node\Stmt\Do_ as DoStmt;
+use PhpParser\Node\Stmt\Function_ as FunctionStmt;
+use PhpParser\Node\Stmt\If_ as IfStmt;
+use PhpParser\Node\Stmt\Switch_ as SwitchStmt;
+use PhpParser\Node\Stmt\While_ as WhileStmt;
+use Psy\Exception\FatalErrorException;
+
+/**
+ * Validate that function calls will succeed.
+ *
+ * This pass throws a FatalErrorException rather than letting PHP run
+ * headfirst into a real fatal error and die.
+ */
+class ValidFunctionNamePass extends NamespaceAwarePass
+{
+ private $conditionalScopes = 0;
+
+ /**
+ * Store newly defined function names on the way in, to allow recursion.
+ *
+ * @param Node $node
+ */
+ public function enterNode(Node $node)
+ {
+ parent::enterNode($node);
+
+ if (self::isConditional($node)) {
+ $this->conditionalScopes++;
+ } elseif ($node instanceof FunctionStmt) {
+ $name = $this->getFullyQualifiedName($node->name);
+
+ // TODO: add an "else" here which adds a runtime check for instances where we can't tell
+ // whether a function is being redefined by static analysis alone.
+ if ($this->conditionalScopes === 0) {
+ if (function_exists($name) ||
+ isset($this->currentScope[strtolower($name)])) {
+ $msg = sprintf('Cannot redeclare %s()', $name);
+ throw new FatalErrorException($msg, 0, 1, null, $node->getLine());
+ }
+ }
+
+ $this->currentScope[strtolower($name)] = true;
+ }
+ }
+
+ /**
+ * Validate that function calls will succeed.
+ *
+ * @throws FatalErrorException if a function is redefined
+ * @throws FatalErrorException if the function name is a string (not an expression) and is not defined
+ *
+ * @param Node $node
+ */
+ public function leaveNode(Node $node)
+ {
+ if (self::isConditional($node)) {
+ $this->conditionalScopes--;
+ } elseif ($node instanceof FuncCall) {
+ // if function name is an expression or a variable, give it a pass for now.
+ $name = $node->name;
+ if (!$name instanceof Expr && !$name instanceof Variable) {
+ $shortName = implode('\\', $name->parts);
+ $fullName = $this->getFullyQualifiedName($name);
+ $inScope = isset($this->currentScope[strtolower($fullName)]);
+ if (!$inScope && !function_exists($shortName) && !function_exists($fullName)) {
+ $message = sprintf('Call to undefined function %s()', $name);
+ throw new FatalErrorException($message, 0, 1, null, $node->getLine());
+ }
+ }
+ }
+ }
+
+ private static function isConditional(Node $node)
+ {
+ return $node instanceof IfStmt ||
+ $node instanceof WhileStmt ||
+ $node instanceof DoStmt ||
+ $node instanceof SwitchStmt;
+ }
+}