Export of internal Abseil changes

--
cf6037b985b629c253b8a87e4408c88a61baf89a by Abseil Team <absl-team@google.com>:

Adds an example of using ABSL_DEPRECATED on a template.
Without this, it's unclear where to add this annotation (e.g. before template <> or after it).

PiperOrigin-RevId: 270057224

--
c53bc14dd683cc1e41c940a337001b42a0270eaf by Andy Getzendanner <durandal@google.com>:

Parser and unparser for command-line flags of type absl::LogSeverity.

PiperOrigin-RevId: 269939999

--
d91174b02f3b213f0b26701d9d97c79f809e6fea by Abseil Team <absl-team@google.com>:

Fix a typo.

PiperOrigin-RevId: 269738777
GitOrigin-RevId: cf6037b985b629c253b8a87e4408c88a61baf89a
Change-Id: I6cec3101014e4c77f4ff2edb4c91740982dbb459

5 files changed, 183 insertions, 5 deletions

diff --git a/absl/base/BUILD.bazel b/absl/base/BUILD.bazel
index a2e510f8d32e..57caa0656e59 100644
--- a/absl/base/BUILD.bazel
+++ b/absl/base/BUILD.bazel
@@ -575,6 +575,8 @@ cc_test(
     linkopts = ABSL_DEFAULT_LINKOPTS,
     deps = [
         ":log_severity",
+        "//absl/flags:marshalling",
+        "//absl/strings",
         "@com_google_googletest//:gtest_main",
     ],
 )
diff --git a/absl/base/CMakeLists.txt b/absl/base/CMakeLists.txt
index 15a92f5fbd2e..2f11ef86556f 100644
--- a/absl/base/CMakeLists.txt
+++ b/absl/base/CMakeLists.txt
@@ -529,7 +529,9 @@ absl_cc_test(
   SRCS
     "log_severity_test.cc"
   DEPS
+    absl::flags_marshalling
     absl::log_severity
+    absl::strings
     gmock
     gtest_main
 )
diff --git a/absl/base/log_severity.h b/absl/base/log_severity.h
index 5a1d5576ce7b..f5dc7d266120 100644
--- a/absl/base/log_severity.h
+++ b/absl/base/log_severity.h
@@ -25,6 +25,19 @@ namespace absl {
 // Four severity levels are defined.  Logging APIs should terminate the program
 // when a message is logged at severity `kFatal`; the other levels have no
 // special semantics.
+//
+// Abseil flags may be defined with type `LogSeverity`.  Dependency layering
+// constraints require that the `AbslParseFlag` overload be declared and defined
+// in the flags module rather than here.  The `AbslUnparseFlag` overload is
+// defined there too for consistency.
+//
+// The parser accepts arbitrary integers (as if the type were `int`).  It also
+// accepts each named enumerator, without regard for case, with or without the
+// leading 'k'.  For example: "kInfo", "INFO", and "info" all parse to the value
+// `absl::LogSeverity::kInfo`.
+//
+// Unparsing a flag produces the same result as `absl::LogSeverityName()` for
+// the standard levels and a base-ten integer otherwise.
 enum class LogSeverity : int {
   kInfo = 0,
   kWarning = 1,
@@ -40,7 +53,7 @@ constexpr std::array<absl::LogSeverity, 4> LogSeverities() {
 }
 
 // Returns the all-caps string representation (e.g. "INFO") of the specified
-// severity level if it is one of the normal levels and "UNKNOWN" otherwise.
+// severity level if it is one of the standard levels and "UNKNOWN" otherwise.
 constexpr const char* LogSeverityName(absl::LogSeverity s) {
   return s == absl::LogSeverity::kInfo
              ? "INFO"
@@ -59,7 +72,7 @@ constexpr absl::LogSeverity NormalizeLogSeverity(absl::LogSeverity s) {
              : s > absl::LogSeverity::kFatal ? absl::LogSeverity::kError : s;
 }
 constexpr absl::LogSeverity NormalizeLogSeverity(int s) {
-  return NormalizeLogSeverity(static_cast<absl::LogSeverity>(s));
+  return absl::NormalizeLogSeverity(static_cast<absl::LogSeverity>(s));
 }
 
 // The exact representation of a streamed `absl::LogSeverity` is deliberately
diff --git a/absl/base/log_severity_test.cc b/absl/base/log_severity_test.cc
index 1de2d101bfa8..1e3aafa56619 100644
--- a/absl/base/log_severity_test.cc
+++ b/absl/base/log_severity_test.cc
@@ -14,14 +14,25 @@
 
 #include "absl/base/log_severity.h"
 
+#include <cstdint>
+#include <ios>
+#include <limits>
+#include <ostream>
 #include <sstream>
 #include <string>
+#include <tuple>
 
 #include "gmock/gmock.h"
 #include "gtest/gtest.h"
+#include "absl/flags/marshalling.h"
+#include "absl/strings/str_cat.h"
 
 namespace {
-using testing::Eq;
+using ::testing::Eq;
+using ::testing::IsFalse;
+using ::testing::IsTrue;
+using ::testing::TestWithParam;
+using ::testing::Values;
 
 std::string StreamHelper(absl::LogSeverity value) {
   std::ostringstream stream;
@@ -40,4 +51,149 @@ TEST(StreamTest, Works) {
               Eq("absl::LogSeverity(4)"));
 }
 
+using ParseFlagFromOutOfRangeIntegerTest = TestWithParam<int64_t>;
+INSTANTIATE_TEST_SUITE_P(
+    Instantiation, ParseFlagFromOutOfRangeIntegerTest,
+    Values(static_cast<int64_t>(std::numeric_limits<int>::min()) - 1,
+           static_cast<int64_t>(std::numeric_limits<int>::max()) + 1));
+TEST_P(ParseFlagFromOutOfRangeIntegerTest, ReturnsError) {
+  const std::string to_parse = absl::StrCat(GetParam());
+  absl::LogSeverity value;
+  std::string error;
+  EXPECT_THAT(absl::ParseFlag(to_parse, &value, &error), IsFalse()) << value;
+}
+
+using ParseFlagFromAlmostOutOfRangeIntegerTest = TestWithParam<int>;
+INSTANTIATE_TEST_SUITE_P(Instantiation,
+                         ParseFlagFromAlmostOutOfRangeIntegerTest,
+                         Values(std::numeric_limits<int>::min(),
+                                std::numeric_limits<int>::max()));
+TEST_P(ParseFlagFromAlmostOutOfRangeIntegerTest, YieldsExpectedValue) {
+  const auto expected = static_cast<absl::LogSeverity>(GetParam());
+  const std::string to_parse = absl::StrCat(GetParam());
+  absl::LogSeverity value;
+  std::string error;
+  ASSERT_THAT(absl::ParseFlag(to_parse, &value, &error), IsTrue()) << error;
+  EXPECT_THAT(value, Eq(expected));
+}
+
+using ParseFlagFromIntegerMatchingEnumeratorTest =
+    TestWithParam<std::tuple<absl::string_view, absl::LogSeverity>>;
+INSTANTIATE_TEST_SUITE_P(
+    Instantiation, ParseFlagFromIntegerMatchingEnumeratorTest,
+    Values(std::make_tuple("0", absl::LogSeverity::kInfo),
+           std::make_tuple(" 0", absl::LogSeverity::kInfo),
+           std::make_tuple("-0", absl::LogSeverity::kInfo),
+           std::make_tuple("+0", absl::LogSeverity::kInfo),
+           std::make_tuple("00", absl::LogSeverity::kInfo),
+           std::make_tuple("0 ", absl::LogSeverity::kInfo),
+           std::make_tuple("0x0", absl::LogSeverity::kInfo),
+           std::make_tuple("1", absl::LogSeverity::kWarning),
+           std::make_tuple("+1", absl::LogSeverity::kWarning),
+           std::make_tuple("2", absl::LogSeverity::kError),
+           std::make_tuple("3", absl::LogSeverity::kFatal)));
+TEST_P(ParseFlagFromIntegerMatchingEnumeratorTest, YieldsExpectedValue) {
+  const absl::string_view to_parse = std::get<0>(GetParam());
+  const absl::LogSeverity expected = std::get<1>(GetParam());
+  absl::LogSeverity value;
+  std::string error;
+  ASSERT_THAT(absl::ParseFlag(to_parse, &value, &error), IsTrue()) << error;
+  EXPECT_THAT(value, Eq(expected));
+}
+
+using ParseFlagFromOtherIntegerTest =
+    TestWithParam<std::tuple<absl::string_view, int>>;
+INSTANTIATE_TEST_SUITE_P(Instantiation, ParseFlagFromOtherIntegerTest,
+                         Values(std::make_tuple("-1", -1),
+                                std::make_tuple("4", 4),
+                                std::make_tuple("010", 10),
+                                std::make_tuple("0x10", 16)));
+TEST_P(ParseFlagFromOtherIntegerTest, YieldsExpectedValue) {
+  const absl::string_view to_parse = std::get<0>(GetParam());
+  const auto expected = static_cast<absl::LogSeverity>(std::get<1>(GetParam()));
+  absl::LogSeverity value;
+  std::string error;
+  ASSERT_THAT(absl::ParseFlag(to_parse, &value, &error), IsTrue()) << error;
+  EXPECT_THAT(value, Eq(expected));
+}
+
+using ParseFlagFromEnumeratorTest =
+    TestWithParam<std::tuple<absl::string_view, absl::LogSeverity>>;
+INSTANTIATE_TEST_SUITE_P(
+    Instantiation, ParseFlagFromEnumeratorTest,
+    Values(std::make_tuple("INFO", absl::LogSeverity::kInfo),
+           std::make_tuple("info", absl::LogSeverity::kInfo),
+           std::make_tuple("kInfo", absl::LogSeverity::kInfo),
+           std::make_tuple("iNfO", absl::LogSeverity::kInfo),
+           std::make_tuple("kInFo", absl::LogSeverity::kInfo),
+           std::make_tuple("WARNING", absl::LogSeverity::kWarning),
+           std::make_tuple("warning", absl::LogSeverity::kWarning),
+           std::make_tuple("kWarning", absl::LogSeverity::kWarning),
+           std::make_tuple("WaRnInG", absl::LogSeverity::kWarning),
+           std::make_tuple("KwArNiNg", absl::LogSeverity::kWarning),
+           std::make_tuple("ERROR", absl::LogSeverity::kError),
+           std::make_tuple("error", absl::LogSeverity::kError),
+           std::make_tuple("kError", absl::LogSeverity::kError),
+           std::make_tuple("eRrOr", absl::LogSeverity::kError),
+           std::make_tuple("kErRoR", absl::LogSeverity::kError),
+           std::make_tuple("FATAL", absl::LogSeverity::kFatal),
+           std::make_tuple("fatal", absl::LogSeverity::kFatal),
+           std::make_tuple("kFatal", absl::LogSeverity::kFatal),
+           std::make_tuple("FaTaL", absl::LogSeverity::kFatal),
+           std::make_tuple("KfAtAl", absl::LogSeverity::kFatal)));
+TEST_P(ParseFlagFromEnumeratorTest, YieldsExpectedValue) {
+  const absl::string_view to_parse = std::get<0>(GetParam());
+  const absl::LogSeverity expected = std::get<1>(GetParam());
+  absl::LogSeverity value;
+  std::string error;
+  ASSERT_THAT(absl::ParseFlag(to_parse, &value, &error), IsTrue()) << error;
+  EXPECT_THAT(value, Eq(expected));
+}
+
+using ParseFlagFromGarbageTest = TestWithParam<absl::string_view>;
+INSTANTIATE_TEST_SUITE_P(Instantiation, ParseFlagFromGarbageTest,
+                         Values("", "\0", " ", "garbage", "kkinfo", "I"));
+TEST_P(ParseFlagFromGarbageTest, ReturnsError) {
+  const absl::string_view to_parse = GetParam();
+  absl::LogSeverity value;
+  std::string error;
+  EXPECT_THAT(absl::ParseFlag(to_parse, &value, &error), IsFalse()) << value;
+}
+
+using UnparseFlagToEnumeratorTest =
+    TestWithParam<std::tuple<absl::LogSeverity, absl::string_view>>;
+INSTANTIATE_TEST_SUITE_P(
+    Instantiation, UnparseFlagToEnumeratorTest,
+    Values(std::make_tuple(absl::LogSeverity::kInfo, "INFO"),
+           std::make_tuple(absl::LogSeverity::kWarning, "WARNING"),
+           std::make_tuple(absl::LogSeverity::kError, "ERROR"),
+           std::make_tuple(absl::LogSeverity::kFatal, "FATAL")));
+TEST_P(UnparseFlagToEnumeratorTest, ReturnsExpectedValueAndRoundTrips) {
+  const absl::LogSeverity to_unparse = std::get<0>(GetParam());
+  const absl::string_view expected = std::get<1>(GetParam());
+  const std::string stringified_value = absl::UnparseFlag(to_unparse);
+  EXPECT_THAT(stringified_value, Eq(expected));
+  absl::LogSeverity reparsed_value;
+  std::string error;
+  EXPECT_THAT(absl::ParseFlag(stringified_value, &reparsed_value, &error),
+              IsTrue());
+  EXPECT_THAT(reparsed_value, Eq(to_unparse));
+}
+
+using UnparseFlagToOtherIntegerTest = TestWithParam<int>;
+INSTANTIATE_TEST_SUITE_P(Instantiation, UnparseFlagToOtherIntegerTest,
+                         Values(std::numeric_limits<int>::min(), -1, 4,
+                                std::numeric_limits<int>::max()));
+TEST_P(UnparseFlagToOtherIntegerTest, ReturnsExpectedValueAndRoundTrips) {
+  const absl::LogSeverity to_unparse =
+      static_cast<absl::LogSeverity>(GetParam());
+  const std::string expected = absl::StrCat(GetParam());
+  const std::string stringified_value = absl::UnparseFlag(to_unparse);
+  EXPECT_THAT(stringified_value, Eq(expected));
+  absl::LogSeverity reparsed_value;
+  std::string error;
+  EXPECT_THAT(absl::ParseFlag(stringified_value, &reparsed_value, &error),
+              IsTrue());
+  EXPECT_THAT(reparsed_value, Eq(to_unparse));
+}
 }  // namespace
diff --git a/absl/base/macros.h b/absl/base/macros.h
index 606a90ac0cca..d481288f35f9 100644
--- a/absl/base/macros.h
+++ b/absl/base/macros.h
@@ -137,10 +137,15 @@ enum LinkerInitialized {
 // declarations. The macro argument is used as a custom diagnostic message (e.g.
 // suggestion of a better alternative).
 //
-// Example:
+// Examples:
 //
 //   class ABSL_DEPRECATED("Use Bar instead") Foo {...};
-//   ABSL_DEPRECATED("Use Baz instead") void Bar() {...}
+//
+//   ABSL_DEPRECATED("Use Baz() instead") void Bar() {...}
+//
+//   template <typename T>
+//   ABSL_DEPRECATED("Use DoThat() instead")
+//   void DoThis();
 //
 // Every usage of a deprecated entity will trigger a warning when compiled with
 // clang's `-Wdeprecated-declarations` option. This option is turned off by