From 8f8a1a02d5c5cb967d240feee3ffac00d66f22a2 Mon Sep 17 00:00:00 2001
From: Victor Zverovich <viz@fb.com>
Date: Fri, 14 Jan 2022 13:08:14 -0800
Subject: [PATCH] Fix handling of formattable types implicitly convertible to
pointers
---
include/fmt/core.h | 5 +++--
test/core-test.cc | 21 ++++++++++++++++++++-
2 files changed, 23 insertions(+), 3 deletions(-)
diff --git a/include/fmt/core.h b/include/fmt/core.h
index f2d21e5c5a..12571ce0da 100644
--- a/include/fmt/core.h
+++ b/include/fmt/core.h
@@ -1398,10 +1398,11 @@ template <typename Context> struct arg_mapper {
template <
typename T,
FMT_ENABLE_IF(
- std::is_member_pointer<T>::value ||
+ std::is_pointer<T>::value || std::is_member_pointer<T>::value ||
std::is_function<typename std::remove_pointer<T>::type>::value ||
(std::is_convertible<const T&, const void*>::value &&
- !std::is_convertible<const T&, const char_type*>::value))>
+ !std::is_convertible<const T&, const char_type*>::value &&
+ !has_formatter<T, Context>::value))>
FMT_CONSTEXPR auto map(const T&) -> unformattable_pointer {
return {};
}
diff --git a/test/core-test.cc b/test/core-test.cc
index b2f2097ea1..c9eea8ffd8 100644
--- a/test/core-test.cc
+++ b/test/core-test.cc
@@ -737,6 +737,24 @@ struct convertible_to_pointer {
operator const int*() const { return nullptr; }
};
+struct convertible_to_pointer_formattable {
+ operator const int*() const { return nullptr; }
+};
+
+FMT_BEGIN_NAMESPACE
+template <> struct formatter<convertible_to_pointer_formattable> {
+ auto parse(format_parse_context& ctx) -> decltype(ctx.begin()) {
+ return ctx.begin();
+ }
+
+ auto format(convertible_to_pointer_formattable, format_context& ctx) const
+ -> decltype(ctx.out()) {
+ auto test = string_view("test");
+ return std::copy_n(test.data(), test.size(), ctx.out());
+ }
+};
+FMT_END_NAMESPACE
+
enum class test_scoped_enum {};
TEST(core_test, is_formattable) {
@@ -770,11 +788,12 @@ TEST(core_test, is_formattable) {
#endif
static_assert(!fmt::is_formattable<convertible_to_pointer>::value, "");
+ const auto f = convertible_to_pointer_formattable();
+ EXPECT_EQ(fmt::format("{}", f), "test");
static_assert(!fmt::is_formattable<void (*)()>::value, "");
struct s;
-
static_assert(!fmt::is_formattable<int(s::*)>::value, "");
static_assert(!fmt::is_formattable<int (s::*)()>::value, "");
static_assert(!fmt::is_formattable<test_scoped_enum>::value, "");