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

1 files changed, 15 insertions, 2 deletions

diff --git a/absl/base/log_severity.h b/absl/base/log_severity.h
index 5a1d5576..f5dc7d26 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