Add ABSL_ATTRIBUTE_LIFETIME_BOUND and a doc note about absl::LogAsLiteral to clarify its intended use.

PiperOrigin-RevId: 696592874
Change-Id: I6d6bc4690f891fbbdd8489b2e2f6398b43d63001

Author: suertreus

absl/log/BUILD.bazel

@@ -234,6 +234,7 @@ cc_library(
     linkopts = ABSL_DEFAULT_LINKOPTS,
     deps = [
         "//absl/base:config",
+        "//absl/base:core_headers",
         "//absl/log/internal:structured",
         "//absl/strings",
     ],

absl/log/CMakeLists.txt

@@ -665,6 +665,7 @@ absl_cc_library(
     ${ABSL_DEFAULT_LINKOPTS}
   DEPS
     absl::config
+    absl::core_headers
     absl::log_internal_message
     absl::strings
 )
@@ -680,6 +681,7 @@ absl_cc_library(
     ${ABSL_DEFAULT_LINKOPTS}
   DEPS
     absl::config
+    absl::core_headers
     absl::log_internal_structured
     absl::strings
   PUBLIC

absl/log/internal/BUILD.bazel

@@ -281,6 +281,7 @@ cc_library(
     deps = [
         ":log_message",
         "//absl/base:config",
+        "//absl/base:core_headers",
         "//absl/strings",
     ],
 )

absl/log/internal/structured.h

@@ -22,6 +22,7 @@
 #include <ostream>
 
 #include "absl/base/config.h"
+#include "absl/base/attributes.h"
 #include "absl/log/internal/log_message.h"
 #include "absl/strings/string_view.h"
 
@@ -31,14 +32,16 @@ namespace log_internal {
 
 class ABSL_MUST_USE_RESULT AsLiteralImpl final {
  public:
-  explicit AsLiteralImpl(absl::string_view str) : str_(str) {}
+  explicit AsLiteralImpl(absl::string_view str ABSL_ATTRIBUTE_LIFETIME_BOUND)
+      : str_(str) {}
   AsLiteralImpl(const AsLiteralImpl&) = default;
   AsLiteralImpl& operator=(const AsLiteralImpl&) = default;
 
  private:
   absl::string_view str_;
 
-  friend std::ostream& operator<<(std::ostream& os, AsLiteralImpl as_literal) {
+  friend std::ostream& operator<<(std::ostream& os,
+                                  AsLiteralImpl&& as_literal) {
     return os << as_literal.str_;
   }
   void AddToMessage(log_internal::LogMessage& m) {

absl/log/structured.h

@@ -32,6 +32,7 @@
 
 #include <ostream>
 
+#include "absl/base/attributes.h"
 #include "absl/base/config.h"
 #include "absl/log/internal/structured.h"
 #include "absl/strings/string_view.h"
@@ -60,7 +61,11 @@ ABSL_NAMESPACE_BEGIN
 //                                 int line) {
 //     LOG(LEVEL(severity)).AtLocation(file, line) << absl::LogAsLiteral(str);
 //   }
-inline log_internal::AsLiteralImpl LogAsLiteral(absl::string_view s) {
+//
+// `LogAsLiteral` should only be used as a streaming operand and not, for
+// example, as a local variable initializer.
+inline log_internal::AsLiteralImpl LogAsLiteral(
+    absl::string_view s ABSL_ATTRIBUTE_LIFETIME_BOUND) {
   return log_internal::AsLiteralImpl(s);
 }