Make the n specifier an opt-in

include/fmt/format.h

@@ -1234,7 +1234,9 @@ FMT_CONSTEXPR void handle_int_type_spec(char spec, Handler&& handler) {
   case 'o':
     handler.on_oct();
     break;
+#ifdef FMT_DEPRECATED_N_SPECIFIER
   case 'n':
+#endif
   case 'L':
     handler.on_num();
     break;
@@ -1282,7 +1284,9 @@ FMT_CONSTEXPR float_specs parse_float_type_spec(
   case 'a':
     result.format = float_format::hex;
     break;
+#ifdef FMT_DEPRECATED_N_SPECIFIER
   case 'n':
+#endif
   case 'L':
     result.locale = true;
     break;

test/format-test.cc

@@ -1223,7 +1223,6 @@ TEST(FormatterTest, FormatOct) {
 }
 
 TEST(FormatterTest, FormatIntLocale) {
-  EXPECT_EQ("1234", format("{:n}", 1234));
   EXPECT_EQ("1234", format("{:L}", 1234));
 }
 
@@ -1320,7 +1319,7 @@ TEST(FormatterTest, FormatLongDouble) {
 }
 
 TEST(FormatterTest, FormatChar) {
-  const char types[] = "cbBdoxXnL";
+  const char types[] = "cbBdoxXL";
   check_unknown_types('a', types, "char");
   EXPECT_EQ("a", format("{0}", 'a'));
   EXPECT_EQ("z", format("{0:c}", 'z'));

test/locale-test.cc

@@ -42,50 +42,50 @@ template <typename Char> struct small_grouping : std::numpunct<Char> {
 
 TEST(LocaleTest, DoubleDecimalPoint) {
   std::locale loc(std::locale(), new numpunct<char>());
-  EXPECT_EQ("1?23", fmt::format(loc, "{:n}", 1.23));
+  EXPECT_EQ("1?23", fmt::format(loc, "{:L}", 1.23));
 }
 
 TEST(LocaleTest, Format) {
   std::locale loc(std::locale(), new numpunct<char>());
-  EXPECT_EQ("1234567", fmt::format(std::locale(), "{:n}", 1234567));
-  EXPECT_EQ("1~234~567", fmt::format(loc, "{:n}", 1234567));
-  EXPECT_EQ("-1~234~567", fmt::format(loc, "{:n}", -1234567));
+  EXPECT_EQ("1234567", fmt::format(std::locale(), "{:L}", 1234567));
+  EXPECT_EQ("1~234~567", fmt::format(loc, "{:L}", 1234567));
+  EXPECT_EQ("-1~234~567", fmt::format(loc, "{:L}", -1234567));
   fmt::format_arg_store<fmt::format_context, int> as{1234567};
-  EXPECT_EQ("1~234~567", fmt::vformat(loc, "{:n}", fmt::format_args(as)));
+  EXPECT_EQ("1~234~567", fmt::vformat(loc, "{:L}", fmt::format_args(as)));
   std::string s;
-  fmt::format_to(std::back_inserter(s), loc, "{:n}", 1234567);
+  fmt::format_to(std::back_inserter(s), loc, "{:L}", 1234567);
   EXPECT_EQ("1~234~567", s);
 
   std::locale no_grouping_loc(std::locale(), new no_grouping<char>());
-  EXPECT_EQ("1234567", fmt::format(no_grouping_loc, "{:n}", 1234567));
+  EXPECT_EQ("1234567", fmt::format(no_grouping_loc, "{:L}", 1234567));
 
   std::locale special_grouping_loc(std::locale(), new special_grouping<char>());
-  EXPECT_EQ("1,23,45,678", fmt::format(special_grouping_loc, "{:n}", 12345678));
+  EXPECT_EQ("1,23,45,678", fmt::format(special_grouping_loc, "{:L}", 12345678));
 
   std::locale small_grouping_loc(std::locale(), new small_grouping<char>());
   EXPECT_EQ("4,2,9,4,9,6,7,2,9,5",
-            fmt::format(small_grouping_loc, "{:n}", max_value<uint32_t>()));
+            fmt::format(small_grouping_loc, "{:L}", max_value<uint32_t>()));
 }
 
 TEST(LocaleTest, WFormat) {
   std::locale loc(std::locale(), new numpunct<wchar_t>());
-  EXPECT_EQ(L"1234567", fmt::format(std::locale(), L"{:n}", 1234567));
-  EXPECT_EQ(L"1~234~567", fmt::format(loc, L"{:n}", 1234567));
+  EXPECT_EQ(L"1234567", fmt::format(std::locale(), L"{:L}", 1234567));
+  EXPECT_EQ(L"1~234~567", fmt::format(loc, L"{:L}", 1234567));
   fmt::format_arg_store<fmt::wformat_context, int> as{1234567};
-  EXPECT_EQ(L"1~234~567", fmt::vformat(loc, L"{:n}", fmt::wformat_args(as)));
-  EXPECT_EQ(L"1234567", fmt::format(std::locale("C"), L"{:n}", 1234567));
+  EXPECT_EQ(L"1~234~567", fmt::vformat(loc, L"{:L}", fmt::wformat_args(as)));
+  EXPECT_EQ(L"1234567", fmt::format(std::locale("C"), L"{:L}", 1234567));
 
   std::locale no_grouping_loc(std::locale(), new no_grouping<wchar_t>());
-  EXPECT_EQ(L"1234567", fmt::format(no_grouping_loc, L"{:n}", 1234567));
+  EXPECT_EQ(L"1234567", fmt::format(no_grouping_loc, L"{:L}", 1234567));
 
   std::locale special_grouping_loc(std::locale(),
                                    new special_grouping<wchar_t>());
   EXPECT_EQ(L"1,23,45,678",
-            fmt::format(special_grouping_loc, L"{:n}", 12345678));
+            fmt::format(special_grouping_loc, L"{:L}", 12345678));
 
   std::locale small_grouping_loc(std::locale(), new small_grouping<wchar_t>());
   EXPECT_EQ(L"4,2,9,4,9,6,7,2,9,5",
-            fmt::format(small_grouping_loc, L"{:n}", max_value<uint32_t>()));
+            fmt::format(small_grouping_loc, L"{:L}", max_value<uint32_t>()));
 }
 
 #endif  // FMT_STATIC_THOUSANDS_SEPARATOR

test/std-format-test.cc

@@ -62,7 +62,7 @@ TEST(StdFormatTest, Int) {
   string s0 = format("{}", 42);                       // s0 == "42"
   string s1 = format("{0:b} {0:d} {0:o} {0:x}", 42);  // s1 == "101010 42 52 2a"
   string s2 = format("{0:#x} {0:#X}", 42);            // s2 == "0x2a 0X2A"
-  string s3 = format("{:n}", 1234);  // s3 == "1234" (depends on the locale)
+  string s3 = format("{:L}", 1234);  // s3 == "1234" (depends on the locale)
   EXPECT_EQ(s0, "42");
   EXPECT_EQ(s1, "101010 42 52 2a");
   EXPECT_EQ(s2, "0x2a 0X2A");