Export of internal Abseil changes

--
fb671efb2a70f452f17a884b17cf18817b977a8f by Abseil Team <absl-team@google.com>:

Remove extra semicolon in ABSL_INTERNAL_ASSERT_IS_FULL macro

To fix compilation when empty statement warning is treated as error.

PiperOrigin-RevId: 438342663
Change-Id: I3067fbeffa2691888f37554e88f229f24fb55ecc

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a58c9396f1d88d11347aed36ef2e1b633071363c by Martijn Vels <mvels@google.com>:

Fix kMaxHeight bounds to kMaxDepth for CordrepBtreeNavigator

Added unit test (confirmed failure mode with old code) and extra assertion in the implementation.

PiperOrigin-RevId: 438327463
Change-Id: I32242c86b0c879b8a42cb9a92075e537d588e09f

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f348e85dbfc9187ef59085fa2b999374f1670338 by Jorge Gorbe Moya <jgorbe@google.com>:

Make the flags enum in `RefcountAndFlags` a named enum to workaround an lldb
issue (https://github.com/llvm/llvm-project/issues/54602).

PiperOrigin-RevId: 438146097
Change-Id: Ibc2ee26489d99de515a779a903b6458dd0befef7

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a960a3e9fb2a2e3418f806178e73d8566b78bc85 by Gennadiy Rozental <rogeeff@google.com>:

Introduce support for std::optional<T>/absl::optional<T> flag types.

PiperOrigin-RevId: 438129500
Change-Id: I3d925c0a7f9ce9f857277fac3b0bf664ccd3a95c
GitOrigin-RevId: fb671efb2a70f452f17a884b17cf18817b977a8f

1 files changed, 56 insertions, 1 deletions

diff --git a/absl/flags/marshalling.h b/absl/flags/marshalling.h
index 7cbc136d..0f63cdc5 100644
--- a/absl/flags/marshalling.h
+++ b/absl/flags/marshalling.h
@@ -162,14 +162,27 @@
 #ifndef ABSL_FLAGS_MARSHALLING_H_
 #define ABSL_FLAGS_MARSHALLING_H_
 
+#include "absl/base/config.h"
+
+#if defined(ABSL_HAVE_STD_OPTIONAL) && !defined(ABSL_USES_STD_OPTIONAL)
+#include <optional>
+#endif
 #include <string>
 #include <vector>
 
-#include "absl/base/config.h"
 #include "absl/strings/string_view.h"
+#include "absl/types/optional.h"
 
 namespace absl {
 ABSL_NAMESPACE_BEGIN
+
+// Forward declaration to be used inside composable flag parse/unparse
+// implementations
+template <typename T>
+inline bool ParseFlag(absl::string_view input, T* dst, std::string* error);
+template <typename T>
+inline std::string UnparseFlag(const T& v);
+
 namespace flags_internal {
 
 // Overloads of `AbslParseFlag()` and `AbslUnparseFlag()` for fundamental types.
@@ -189,6 +202,36 @@ bool AbslParseFlag(absl::string_view, std::string*, std::string*);
 bool AbslParseFlag(absl::string_view, std::vector<std::string>*, std::string*);
 
 template <typename T>
+bool AbslParseFlag(absl::string_view text, absl::optional<T>* f,
+                   std::string* err) {
+  if (text.empty()) {
+    *f = absl::nullopt;
+    return true;
+  }
+  T value;
+  if (!absl::ParseFlag(text, &value, err)) return false;
+
+  *f = std::move(value);
+  return true;
+}
+
+#if defined(ABSL_HAVE_STD_OPTIONAL) && !defined(ABSL_USES_STD_OPTIONAL)
+template <typename T>
+bool AbslParseFlag(absl::string_view text, std::optional<T>* f,
+                   std::string* err) {
+  if (text.empty()) {
+    *f = std::nullopt;
+    return true;
+  }
+  T value;
+  if (!absl::ParseFlag(text, &value, err)) return false;
+
+  *f = std::move(value);
+  return true;
+}
+#endif
+
+template <typename T>
 bool InvokeParseFlag(absl::string_view input, T* dst, std::string* err) {
   // Comment on next line provides a good compiler error message if T
   // does not have AbslParseFlag(absl::string_view, T*, std::string*).
@@ -202,6 +245,18 @@ std::string AbslUnparseFlag(absl::string_view v);
 std::string AbslUnparseFlag(const std::vector<std::string>&);
 
 template <typename T>
+std::string AbslUnparseFlag(const absl::optional<T>& f) {
+  return f.has_value() ? absl::UnparseFlag(*f) : "";
+}
+
+#if defined(ABSL_HAVE_STD_OPTIONAL) && !defined(ABSL_USES_STD_OPTIONAL)
+template <typename T>
+std::string AbslUnparseFlag(const std::optional<T>& f) {
+  return f.has_value() ? absl::UnparseFlag(*f) : "";
+}
+#endif
+
+template <typename T>
 std::string Unparse(const T& v) {
   // Comment on next line provides a good compiler error message if T does not
   // have UnparseFlag.