Adds support for "%v" in absl::StrFormat and related functions for bool values.…

Adds support for "%v" in absl::StrFormat and related functions for bool values. Note that %v prints bool values as "true" and "false" rather than "1" and "0".

PiperOrigin-RevId: 475651689
Change-Id: I24b3749d85b5bb7cbc18653d629271a8b2b07d08

absl/strings/internal/str_format/arg.cc

@@ -376,6 +376,15 @@ inline bool ConvertStringArg(string_view v, const FormatConversionSpecImpl conv,
 
 }  // namespace
 
+bool ConvertBoolArg(bool v, FormatSinkImpl *sink) {
+  if (v) {
+    sink->Append("true");
+  } else {
+    sink->Append("false");
+  }
+  return true;
+}
+
 // ==================== Strings ====================
 StringConvertResult FormatConvertImpl(const std::string &v,
                                       const FormatConversionSpecImpl conv,

absl/strings/internal/str_format/arg.h

@@ -186,6 +186,8 @@ using CharConvertResult = ArgConvertResult<FormatConversionCharSetUnion(
     FormatConversionCharSetInternal::kNumeric,
     FormatConversionCharSetInternal::kStar)>;
 
+bool ConvertBoolArg(bool v, FormatSinkImpl* sink);
+
 // Floats.
 FloatingConvertResult FormatConvertImpl(float v, FormatConversionSpecImpl conv,
                                         FormatSinkImpl* sink);
@@ -234,9 +236,16 @@ IntegralConvertResult FormatConvertImpl(int128 v, FormatConversionSpecImpl conv,
 IntegralConvertResult FormatConvertImpl(uint128 v,
                                         FormatConversionSpecImpl conv,
                                         FormatSinkImpl* sink);
+
+// This function needs to be a template due to ambiguity regarding type
+// conversions.
 template <typename T, enable_if_t<std::is_same<T, bool>::value, int> = 0>
 IntegralConvertResult FormatConvertImpl(T v, FormatConversionSpecImpl conv,
                                         FormatSinkImpl* sink) {
+  if (conv.conversion_char() == FormatConversionCharInternal::v) {
+    return {ConvertBoolArg(v, sink)};
+  }
+
   return FormatConvertImpl(static_cast<int>(v), conv, sink);
 }
 

absl/strings/str_format_test.cc

@@ -644,6 +644,11 @@ TEST(StrFormat, BehavesAsDocumented) {
   EXPECT_EQ(StrFormat("%zd", int{1}), "1");
   EXPECT_EQ(StrFormat("%td", int{1}), "1");
   EXPECT_EQ(StrFormat("%qd", int{1}), "1");
+
+  // Bool is handled correctly depending on whether %v is used
+  EXPECT_EQ(StrFormat("%v", true), "true");
+  EXPECT_EQ(StrFormat("%v", false), "false");
+  EXPECT_EQ(StrFormat("%d", true), "1");
 }
 
 using str_format_internal::ExtendedParsedFormat;