fix(stub): harden heredoc and nowdoc C++ escaping

src/gen_stub.php

@@ -834,7 +834,10 @@ class ArgInfo {
 
     private function getDefaultValueAsArginfoString(): string {
         if ($this->hasProperDefaultValue()) {
-            return '"' . addslashes($this->defaultValue) . '"';
+            // The default value is a PHP expression embedded in a C string.
+            // Escape for the outer C layer only; addslashes() leaves line
+            // breaks and other control bytes untouched, producing invalid C++.
+            return '"' . getTranslator()->escapeString($this->defaultValue) . '"';
         }
 
         return "NULL";
@@ -2485,7 +2488,9 @@ class EvaluatedValue
                 if ($forStringDef === '') {
                     $forStringDef = "{$zvalName}_str";
                 }
-                $code .= "\tzend_string *$forStringDef = zend_string_init($cExpr, strlen($cExpr), 1);\n";
+                // getCExpr() emits a C string literal here. sizeof() preserves
+                // embedded NUL bytes, unlike strlen().
+                $code .= "\tzend_string *$forStringDef = zend_string_init($cExpr, sizeof($cExpr) - 1, 1);\n";
                 $code .= "\tZVAL_STR(&$zvalName, $forStringDef);\n";
             }
         } elseif ($this->type->isArray()) {
@@ -2515,20 +2520,12 @@ class EvaluatedValue
                 return '"' . getTranslator()->escapeString((string) $this->value) . '"';
             } elseif ($this->expr instanceof Expr\ConstFetch) {
                 return getTranslator()->getConstValue($this->expr->name->toString());
-            } elseif ($this->expr instanceof String_) {
-                // Heredoc/nowdoc and quoted string literals: emit the decoded
-                // value directly. Pretty-printing a heredoc/nowdoc would leak
-                // the `<<<MARKER ... MARKER` source syntax into the generated
-                // C++, which is invalid; for quoted strings this is also the
-                // correct, simpler form.
-                return '"' . getTranslator()->escapeString((string) $this->value) . '"';
-            } else {
-                // ConstExprEvaluator has already reduced concatenations and
-                // other constant string expressions to their PHP value. Emit
-                // that value as a C string literal instead of rejecting every
-                // non-literal string expression.
-                return '"' . getTranslator()->escapeString((string) $this->value) . '"';
             }
+
+            // ConstExprEvaluator has already decoded literal syntax and
+            // reduced constant string expressions. Emitting that value avoids
+            // leaking heredoc/nowdoc source syntax into generated C++.
+            return '"' . getTranslator()->escapeString((string) $this->value) . '"';
         } elseif ($this->type->isInt() or $this->type->isFloat()) {
             return strval($this->value);
         } elseif ($this->type->isBool()) {
@@ -5113,13 +5110,10 @@ function parseFunctionLike(
             if ($param->default instanceof Expr\ClassConstFetch && $param->default->class->toLowerString() === "self") {
                 $defaultValue = getTranslator()->getClassConstValue($func, $name->className->name, $param->default->name->name);
                 $defaultValue = var_export($defaultValue, true);
-            } elseif ($param->default instanceof String_ &&
-                in_array($param->default->getAttribute('kind'), [String_::KIND_HEREDOC, String_::KIND_NOWDOC], true)
-            ) {
-                // heredoc/nowdoc: prettyPrint 会输出 `<<<MARKER ... MARKER` 源码语法，
-                // 在 arginfo 的 C 字符串字面量中属于非法内容；改为输出解码后的字符串值
-                // （PHP 双引号字符串字面量，经 addslashes 包裹后仍可被 arginfo 正确求值）。
-                $defaultValue = '"' . getTranslator()->escapeString((string) $param->default->value) . '"';
+            } elseif ($param->default instanceof String_) {
+                // Keep this as a PHP expression. ArgInfo escapes the expression
+                // separately when embedding it in generated C++.
+                $defaultValue = var_export($param->default->value, true);
             } else {
                 $defaultValue = $param->default ? $prettyPrinter->prettyPrintExpr($param->default) : null;
             }

tests/compiler/const/class-const-heredoc-nowdoc.phpt

@@ -6,18 +6,18 @@ class constants with heredoc and nowdoc syntax
 class Test
 {
     const VALUE1 = <<<ABC
-    abc
+    quote " slash \\ nul \0 tab \t ??
     ABC;
     const VALUE2 = <<<'DEF'
-    def
+    $value ?? "quoted" \n \path
     DEF;
 }
 
 function main()
 {
-    var_dump(Test::VALUE1, Test::VALUE2);
+    var_dump(bin2hex(Test::VALUE1), bin2hex(Test::VALUE2));
 }
 ?>
 --EXPECT--
-string(3) "abc"
-string(3) "def"
+string(60) "71756f7465202220736c617368205c206e756c2000207461622009203f3f"
+string(54) "2476616c7565203f3f202271756f74656422205c6e205c70617468"

tests/compiler/const/heredoc-nowdoc-const-defaults.phpt

@@ -17,8 +17,14 @@ class WithProp
     ABC;
 }
 
-function with_default(string $x = <<<ABC
-abc
+function with_default(string $x = <<<'ABC'
+$value ?? "quoted" \n \path
+ABC): string {
+    return $x;
+}
+
+function with_binary_default(string $x = <<<ABC
+A\0B
 ABC): string {
     return $x;
 }
@@ -28,11 +34,18 @@ function main()
     var_dump(G_HEREDOC, G_NOWDOC);
     $o = new WithProp();
     var_dump($o->p);
-    var_dump(with_default());
+    var_dump(bin2hex(with_default()), bin2hex(with_binary_default()));
+
+    $default = (new ReflectionFunction('with_default'))->getParameters()[0]->getDefaultValue();
+    $binaryDefault = (new ReflectionFunction('with_binary_default'))->getParameters()[0]->getDefaultValue();
+    var_dump(bin2hex($default), bin2hex($binaryDefault));
 }
 ?>
 --EXPECT--
 string(3) "abc"
 string(3) "def"
 string(3) "xyz"
-string(3) "abc"
+string(54) "2476616c7565203f3f202271756f74656422205c6e205c70617468"
+string(6) "410042"
+string(54) "2476616c7565203f3f202271756f74656422205c6e205c70617468"
+string(6) "410042"