From c31d639e15ceb2a1fab05f1318f886df7c18bbcb Mon Sep 17 00:00:00 2001
From: Marc Horowitz <mhorowitz@fb.com>
Date: Tue, 18 Apr 2017 15:21:35 -0700
Subject: [PATCH] Fail on implicit convert from BOOL on ObjC in folly::dynamic
Summary: On some platforms (iPhone 5C at least), ObjC/Objc++ BOOL is really signed char. There is code which expects this to be a boolean when converted to dynamic (and then to JSON and into JS), but the old code treated it as a number. This makes such code (like [mobileConfig getBool:]) fail to compile, so the developer needs to resolve the ambiguity one way or the other.
Reviewed By: yfeldblum
Differential Revision: D4648133
fbshipit-source-id: 76ece7803a1e966dca08bdb857af7990035544a0
---
folly/Portability.h | 6 ++++++
folly/dynamic-inl.h | 3 +++
2 files changed, 9 insertions(+)
diff --git a/folly/Portability.h b/folly/Portability.h
index 1792abf5..51032fda 100644
--- a/folly/Portability.h
+++ b/folly/Portability.h
@@ -331,6 +331,12 @@ using namespace FOLLY_GFLAGS_NAMESPACE;
namespace folly {
+#if __OBJC__
+constexpr auto kIsObjC = true;
+#else
+constexpr auto kIsObjC = false;
+#endif
+
#if defined(__linux__) && !FOLLY_MOBILE
constexpr auto kIsLinux = true;
#else
diff --git a/folly/dynamic-inl.h b/folly/dynamic-inl.h
index dbe36b5d..3c85ee4b 100644
--- a/folly/dynamic-inl.h
+++ b/folly/dynamic-inl.h
@@ -310,6 +310,9 @@ inline dynamic::~dynamic() noexcept { destroy(); }
template <class T>
struct dynamic::NumericTypeHelper<
T, typename std::enable_if<std::is_integral<T>::value>::type> {
+ static_assert(
+ !kIsObjC || sizeof(T) > sizeof(char),
+ "char-sized types are ambiguous in objc; cast to bool or wider type");
using type = int64_t;
};
template <>
--
2.34.1