LibJS: Throw error in Object::to_string() if string conversion fails

abyesilyurt · Apr 29, 2020 · 2c6e7db · 2c6e7db
1 parent 95abcc3
commit 2c6e7db
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Showing 2 changed files with 14 additions and 3 deletions.
diff --git a/Libraries/LibJS/Runtime/Object.cpp b/Libraries/LibJS/Runtime/Object.cpp
@@ -360,7 +360,13 @@ Value Object::to_string() const
  && to_string_property.is_object()
  && to_string_property.as_object().is_function()) {
  auto& to_string_function = static_cast<Function&>(to_string_property.as_object());
- return const_cast<Object*>(this)->interpreter().call(to_string_function, const_cast<Object*>(this));
+ auto& interpreter = const_cast<Object*>(this)->interpreter();
+ auto string_value = interpreter.call(to_string_function, const_cast<Object*>(this));
+ if (!string_value.is_string())
+ interpreter.throw_exception<TypeError>("Cannot convert object to string");
+ if (interpreter.exception())
+ return {};
+ return string_value;
  }
  return js_string(heap(), String::format("[object %s]", class_name()));
 }

diff --git a/Libraries/LibJS/Runtime/Value.cpp b/Libraries/LibJS/Runtime/Value.cpp
@@ -69,8 +69,13 @@ String Value::to_string() const
  return String::format("%.4f", as_double());
  }
 
- if (is_object())
- return as_object().to_primitive(Object::PreferredType::String).to_string();
+ if (is_object()) {
+ auto primitive_value = as_object().to_primitive(Object::PreferredType::String);
+ // FIXME: Maybe we should pass in the Interpreter& and call interpreter.exception() instead?
+ if (primitive_value.is_empty())
+ return {};
+ return primitive_value.to_string();
+ }
 
  if (is_string())
  return m_value.as_string->string();