Export of internal Abseil changes.

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eca34da4ccb7bb6a580f1364dff9ca053418fa3b by Abseil Team <absl-team@google.com>:

Internal change.

PiperOrigin-RevId: 214305433

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35393bdd21a87c4286f945fd34dda93afc4e0cd6 by Abseil Team <absl-team@google.com>:

Move some implementation details of string_view around to facilitate compiling on NVCC.

Abseil does not officially support NVCC as a reminder.

PiperOrigin-RevId: 214184876

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61846cab9ab9476a4676ecade7173f68978cd038 by Jorg Brown <jorg@google.com>:

Move the initialization values for constants back to their declaration.

PiperOrigin-RevId: 214135927

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7ac7df6c5f78f2faf419268c04618b936cb26065 by Abseil Team <absl-team@google.com>:

Performance improvements on format parser.

PiperOrigin-RevId: 214032366

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90b4c0cf20e9feaa257a7ece40adaf7db40a60a7 by Xiaoyi Zhang <zhangxy@google.com>:

Add static_assert check to absl::visit to make sure all overloads of the visitor return the same type, as required by the C++ standard.

PiperOrigin-RevId: 213677001

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787995342101b4c181291cde9ecea3048536e4bd by Abseil Team <absl-team@google.com>:

Update comment to indicate finite durations are less than InfiniteDuration.

PiperOrigin-RevId: 213660328

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d78f0dce7cc31218807e96d93b9e8513b6c80b24 by Jon Cohen <cohenjon@google.com>:

s/invariant/contract in the exceptions safety testing framework.  This is a better term as these can be type invariants or function post conditions.  They also are very similar ground as to what is covered by c++20 Contracts (and could even be replaced by them.

PiperOrigin-RevId: 213631019

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0b3ff1a640de9a7391a6c233568802cf86245b0e by Abseil Team <absl-team@google.com>:

Add noinline attribute for GetStackTrace/GetStackFrames/... so the skipped frames will not change because of inlining difference.

PiperOrigin-RevId: 213009637
GitOrigin-RevId: eca34da4ccb7bb6a580f1364dff9ca053418fa3b
Change-Id: Iff1022fd24e440fcbdf3c4ab2a915ca8954daa31

4 files changed, 68 insertions, 63 deletions

diff --git a/absl/types/any_exception_safety_test.cc b/absl/types/any_exception_safety_test.cc
index cfb82d80445c..f9dd8c482c25 100644
--- a/absl/types/any_exception_safety_test.cc
+++ b/absl/types/any_exception_safety_test.cc
@@ -107,7 +107,7 @@ TEST(AnyExceptionSafety, Assignment) {
   };
   auto any_strong_tester = testing::MakeExceptionSafetyTester()
                                .WithInitialValue(original)
-                               .WithInvariants(AnyInvariants, any_is_strong);
+                               .WithContracts(AnyInvariants, any_is_strong);
 
   Thrower val(2);
   absl::any any_val(val);
@@ -129,7 +129,7 @@ TEST(AnyExceptionSafety, Assignment) {
   auto strong_empty_any_tester =
       testing::MakeExceptionSafetyTester()
           .WithInitialValue(absl::any{})
-          .WithInvariants(AnyInvariants, empty_any_is_strong);
+          .WithContracts(AnyInvariants, empty_any_is_strong);
 
   EXPECT_TRUE(strong_empty_any_tester.Test(assign_any));
   EXPECT_TRUE(strong_empty_any_tester.Test(assign_val));
@@ -142,7 +142,7 @@ TEST(AnyExceptionSafety, Emplace) {
       absl::any{absl::in_place_type_t<Thrower>(), 1, testing::nothrow_ctor};
   auto one_tester = testing::MakeExceptionSafetyTester()
                         .WithInitialValue(initial_val)
-                        .WithInvariants(AnyInvariants, AnyIsEmpty);
+                        .WithContracts(AnyInvariants, AnyIsEmpty);
 
   auto emp_thrower = [](absl::any* ap) { ap->emplace<Thrower>(2); };
   auto emp_throwervec = [](absl::any* ap) {
diff --git a/absl/types/internal/variant.h b/absl/types/internal/variant.h
index f220afd04415..eff4fefed409 100644
--- a/absl/types/internal/variant.h
+++ b/absl/types/internal/variant.h
@@ -1,4 +1,4 @@
-// Copyright 2017 The Abseil Authors.
+// Copyright 2018 The Abseil Authors.
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
@@ -910,6 +910,11 @@ struct PerformVisitation {
   template <std::size_t... TupIs, std::size_t... Is>
   constexpr ReturnType Run(std::false_type /*has_valueless*/,
                            index_sequence<TupIs...>, SizeT<Is>...) const {
+    static_assert(
+        std::is_same<ReturnType,
+                     absl::result_of_t<Op(VariantAccessResult<
+                                          Is, QualifiedVariants>...)>>::value,
+        "All visitation overloads must have the same return type.");
     return absl::base_internal::Invoke(
         absl::forward<Op>(op),
         VariantCoreAccess::Access<Is>(
diff --git a/absl/types/optional_exception_safety_test.cc b/absl/types/optional_exception_safety_test.cc
index 31eb66df5445..d117ee518491 100644
--- a/absl/types/optional_exception_safety_test.cc
+++ b/absl/types/optional_exception_safety_test.cc
@@ -43,7 +43,7 @@ bool ValueThrowsBadOptionalAccess(const OptionalT& optional) try {
 }
 
 template <typename OptionalT>
-AssertionResult CheckInvariants(OptionalT* optional_ptr) {
+AssertionResult OptionalInvariants(OptionalT* optional_ptr) {
   // Check the current state post-throw for validity
   auto& optional = *optional_ptr;
 
@@ -123,8 +123,8 @@ TEST(OptionalExceptionSafety, NothrowConstructors) {
 TEST(OptionalExceptionSafety, Emplace) {
   // Test the basic guarantee plus test the result of optional::has_value()
   // is false in all cases
-  auto disengaged_test = MakeExceptionSafetyTester().WithInvariants(
-      CheckInvariants<Optional>, CheckDisengaged<Optional>);
+  auto disengaged_test = MakeExceptionSafetyTester().WithContracts(
+      OptionalInvariants<Optional>, CheckDisengaged<Optional>);
   auto disengaged_test_empty = disengaged_test.WithInitialValue(Optional());
   auto disengaged_test_nonempty =
       disengaged_test.WithInitialValue(Optional(kInitialInteger));
@@ -147,11 +147,11 @@ TEST(OptionalExceptionSafety, EverythingThrowsSwap) {
   // Test the basic guarantee plus test the result of optional::has_value()
   // remains the same
   auto test =
-      MakeExceptionSafetyTester().WithInvariants(CheckInvariants<Optional>);
+      MakeExceptionSafetyTester().WithContracts(OptionalInvariants<Optional>);
   auto disengaged_test_empty = test.WithInitialValue(Optional())
-                                   .WithInvariants(CheckDisengaged<Optional>);
+                                   .WithContracts(CheckDisengaged<Optional>);
   auto engaged_test_nonempty = test.WithInitialValue(Optional(kInitialInteger))
-                                   .WithInvariants(CheckEngaged<Optional>);
+                                   .WithContracts(CheckEngaged<Optional>);
 
   auto swap_empty = [](Optional* optional_ptr) {
     auto empty = Optional();
@@ -192,11 +192,11 @@ TEST(OptionalExceptionSafety, CopyAssign) {
   // Test the basic guarantee plus test the result of optional::has_value()
   // remains the same
   auto test =
-      MakeExceptionSafetyTester().WithInvariants(CheckInvariants<Optional>);
+      MakeExceptionSafetyTester().WithContracts(OptionalInvariants<Optional>);
   auto disengaged_test_empty = test.WithInitialValue(Optional())
-                                   .WithInvariants(CheckDisengaged<Optional>);
+                                   .WithContracts(CheckDisengaged<Optional>);
   auto engaged_test_nonempty = test.WithInitialValue(Optional(kInitialInteger))
-                                   .WithInvariants(CheckEngaged<Optional>);
+                                   .WithContracts(CheckEngaged<Optional>);
 
   auto copyassign_nonempty = [](Optional* optional_ptr) {
     auto nonempty =
@@ -218,11 +218,11 @@ TEST(OptionalExceptionSafety, MoveAssign) {
   // Test the basic guarantee plus test the result of optional::has_value()
   // remains the same
   auto test =
-      MakeExceptionSafetyTester().WithInvariants(CheckInvariants<Optional>);
+      MakeExceptionSafetyTester().WithContracts(OptionalInvariants<Optional>);
   auto disengaged_test_empty = test.WithInitialValue(Optional())
-                                   .WithInvariants(CheckDisengaged<Optional>);
+                                   .WithContracts(CheckDisengaged<Optional>);
   auto engaged_test_nonempty = test.WithInitialValue(Optional(kInitialInteger))
-                                   .WithInvariants(CheckEngaged<Optional>);
+                                   .WithContracts(CheckEngaged<Optional>);
 
   auto moveassign_empty = [](Optional* optional_ptr) {
     auto empty = Optional();
diff --git a/absl/types/variant_exception_safety_test.cc b/absl/types/variant_exception_safety_test.cc
index a3c9eac33a75..58436f07b843 100644
--- a/absl/types/variant_exception_safety_test.cc
+++ b/absl/types/variant_exception_safety_test.cc
@@ -59,7 +59,7 @@ void ToValuelessByException(ThrowingVariant& v) {  // NOLINT
 }
 
 // Check that variant is still in a usable state after an exception is thrown.
-testing::AssertionResult CheckInvariants(ThrowingVariant* v) {
+testing::AssertionResult VariantInvariants(ThrowingVariant* v) {
   using testing::AssertionFailure;
   using testing::AssertionSuccess;
 
@@ -213,8 +213,8 @@ TEST(VariantExceptionSafetyTest, CopyAssign) {
         MakeExceptionSafetyTester()
             .WithInitialValue(WithThrower())
             .WithOperation([&rhs](ThrowingVariant* lhs) { *lhs = rhs; });
-    EXPECT_TRUE(tester.WithInvariants(CheckInvariants).Test());
-    EXPECT_FALSE(tester.WithInvariants(strong_guarantee).Test());
+    EXPECT_TRUE(tester.WithContracts(VariantInvariants).Test());
+    EXPECT_FALSE(tester.WithContracts(strong_guarantee).Test());
   }
   {
     const ThrowingVariant rhs(ExpectedThrowerVec());
@@ -222,8 +222,8 @@ TEST(VariantExceptionSafetyTest, CopyAssign) {
         MakeExceptionSafetyTester()
             .WithInitialValue(WithThrowerVec())
             .WithOperation([&rhs](ThrowingVariant* lhs) { *lhs = rhs; });
-    EXPECT_TRUE(tester.WithInvariants(CheckInvariants).Test());
-    EXPECT_FALSE(tester.WithInvariants(strong_guarantee).Test());
+    EXPECT_TRUE(tester.WithContracts(VariantInvariants).Test());
+    EXPECT_FALSE(tester.WithContracts(strong_guarantee).Test());
   }
   // libstdc++ std::variant has bugs on copy assignment regarding exception
   // safety.
@@ -251,12 +251,12 @@ TEST(VariantExceptionSafetyTest, CopyAssign) {
             .WithInitialValue(WithCopyNoThrow())
             .WithOperation([&rhs](ThrowingVariant* lhs) { *lhs = rhs; });
     EXPECT_TRUE(tester
-                    .WithInvariants(CheckInvariants,
-                                    [](ThrowingVariant* lhs) {
-                                      return lhs->valueless_by_exception();
-                                    })
+                    .WithContracts(VariantInvariants,
+                                   [](ThrowingVariant* lhs) {
+                                     return lhs->valueless_by_exception();
+                                   })
                     .Test());
-    EXPECT_FALSE(tester.WithInvariants(strong_guarantee).Test());
+    EXPECT_FALSE(tester.WithContracts(strong_guarantee).Test());
   }
 #endif  // !(defined(ABSL_HAVE_STD_VARIANT) && defined(__GLIBCXX__))
   {
@@ -268,7 +268,7 @@ TEST(VariantExceptionSafetyTest, CopyAssign) {
     const ThrowingVariant rhs(MoveNothrow{});
     EXPECT_TRUE(MakeExceptionSafetyTester()
                     .WithInitialValue(WithThrower())
-                    .WithInvariants(CheckInvariants, strong_guarantee)
+                    .WithContracts(VariantInvariants, strong_guarantee)
                     .Test([&rhs](ThrowingVariant* lhs) { *lhs = rhs; }));
   }
 }
@@ -304,11 +304,11 @@ TEST(VariantExceptionSafetyTest, MoveAssign) {
                         *lhs = std::move(copy);
                       });
     EXPECT_TRUE(tester
-                    .WithInvariants(
-                        CheckInvariants,
+                    .WithContracts(
+                        VariantInvariants,
                         [&](ThrowingVariant* lhs) { return lhs->index() == j; })
                     .Test());
-    EXPECT_FALSE(tester.WithInvariants(strong_guarantee).Test());
+    EXPECT_FALSE(tester.WithContracts(strong_guarantee).Test());
   }
   {
     // - otherwise (index() != j), equivalent to
@@ -318,10 +318,10 @@ TEST(VariantExceptionSafetyTest, MoveAssign) {
     ThrowingVariant rhs(CopyNothrow{});
     EXPECT_TRUE(MakeExceptionSafetyTester()
                     .WithInitialValue(WithThrower())
-                    .WithInvariants(CheckInvariants,
-                                    [](ThrowingVariant* lhs) {
-                                      return lhs->valueless_by_exception();
-                                    })
+                    .WithContracts(VariantInvariants,
+                                   [](ThrowingVariant* lhs) {
+                                     return lhs->valueless_by_exception();
+                                   })
                     .Test([&](ThrowingVariant* lhs) {
                       auto copy = rhs;
                       *lhs = std::move(copy);
@@ -347,12 +347,12 @@ TEST(VariantExceptionSafetyTest, ValueAssign) {
             .WithInitialValue(WithThrower())
             .WithOperation([rhs](ThrowingVariant* lhs) { *lhs = rhs; });
     EXPECT_TRUE(copy_tester
-                    .WithInvariants(CheckInvariants,
-                                    [](ThrowingVariant* lhs) {
-                                      return !lhs->valueless_by_exception();
-                                    })
+                    .WithContracts(VariantInvariants,
+                                   [](ThrowingVariant* lhs) {
+                                     return !lhs->valueless_by_exception();
+                                   })
                     .Test());
-    EXPECT_FALSE(copy_tester.WithInvariants(strong_guarantee).Test());
+    EXPECT_FALSE(copy_tester.WithContracts(strong_guarantee).Test());
     // move assign
     auto move_tester = MakeExceptionSafetyTester()
                            .WithInitialValue(WithThrower())
@@ -361,13 +361,13 @@ TEST(VariantExceptionSafetyTest, ValueAssign) {
                              *lhs = std::move(copy);
                            });
     EXPECT_TRUE(move_tester
-                    .WithInvariants(CheckInvariants,
-                                    [](ThrowingVariant* lhs) {
-                                      return !lhs->valueless_by_exception();
-                                    })
+                    .WithContracts(VariantInvariants,
+                                   [](ThrowingVariant* lhs) {
+                                     return !lhs->valueless_by_exception();
+                                   })
                     .Test());
 
-    EXPECT_FALSE(move_tester.WithInvariants(strong_guarantee).Test());
+    EXPECT_FALSE(move_tester.WithContracts(strong_guarantee).Test());
   }
   // Otherwise (*this holds something else), if is_nothrow_constructible_v<Tj,
   // T> || !is_nothrow_move_constructible_v<Tj> is true, equivalent to
@@ -400,12 +400,12 @@ TEST(VariantExceptionSafetyTest, ValueAssign) {
             .WithInitialValue(WithCopyNoThrow())
             .WithOperation([&rhs](ThrowingVariant* lhs) { *lhs = rhs; });
     EXPECT_TRUE(copy_tester
-                    .WithInvariants(CheckInvariants,
-                                    [](ThrowingVariant* lhs) {
-                                      return lhs->valueless_by_exception();
-                                    })
+                    .WithContracts(VariantInvariants,
+                                   [](ThrowingVariant* lhs) {
+                                     return lhs->valueless_by_exception();
+                                   })
                     .Test());
-    EXPECT_FALSE(copy_tester.WithInvariants(strong_guarantee).Test());
+    EXPECT_FALSE(copy_tester.WithContracts(strong_guarantee).Test());
     // move
     auto move_tester = MakeExceptionSafetyTester()
                            .WithInitialValue(WithCopyNoThrow())
@@ -413,12 +413,12 @@ TEST(VariantExceptionSafetyTest, ValueAssign) {
                              *lhs = ExpectedThrower(testing::nothrow_ctor);
                            });
     EXPECT_TRUE(move_tester
-                    .WithInvariants(CheckInvariants,
-                                    [](ThrowingVariant* lhs) {
-                                      return lhs->valueless_by_exception();
-                                    })
+                    .WithContracts(VariantInvariants,
+                                   [](ThrowingVariant* lhs) {
+                                     return lhs->valueless_by_exception();
+                                   })
                     .Test());
-    EXPECT_FALSE(move_tester.WithInvariants(strong_guarantee).Test());
+    EXPECT_FALSE(move_tester.WithContracts(strong_guarantee).Test());
   }
   // Otherwise (if is_nothrow_constructible_v<Tj, T> == false &&
   // is_nothrow_move_constructible<Tj> == true),
@@ -432,7 +432,7 @@ TEST(VariantExceptionSafetyTest, ValueAssign) {
     MoveNothrow rhs;
     EXPECT_TRUE(MakeExceptionSafetyTester()
                     .WithInitialValue(WithThrower())
-                    .WithInvariants(CheckInvariants, strong_guarantee)
+                    .WithContracts(VariantInvariants, strong_guarantee)
                     .Test([&rhs](ThrowingVariant* lhs) { *lhs = rhs; }));
   }
 #endif  // !(defined(ABSL_HAVE_STD_VARIANT) && defined(__GLIBCXX__))
@@ -450,12 +450,12 @@ TEST(VariantExceptionSafetyTest, Emplace) {
                         v->emplace<Thrower>(args);
                       });
     EXPECT_TRUE(tester
-                    .WithInvariants(CheckInvariants,
-                                    [](ThrowingVariant* v) {
-                                      return v->valueless_by_exception();
-                                    })
+                    .WithContracts(VariantInvariants,
+                                   [](ThrowingVariant* v) {
+                                     return v->valueless_by_exception();
+                                   })
                     .Test());
-    EXPECT_FALSE(tester.WithInvariants(strong_guarantee).Test());
+    EXPECT_FALSE(tester.WithContracts(strong_guarantee).Test());
   }
 }
 
@@ -472,7 +472,7 @@ TEST(VariantExceptionSafetyTest, Swap) {
     ThrowingVariant rhs = ExpectedThrower();
     EXPECT_TRUE(MakeExceptionSafetyTester()
                     .WithInitialValue(WithThrower())
-                    .WithInvariants(CheckInvariants)
+                    .WithContracts(VariantInvariants)
                     .Test([&](ThrowingVariant* lhs) {
                       auto copy = rhs;
                       lhs->swap(copy);
@@ -486,7 +486,7 @@ TEST(VariantExceptionSafetyTest, Swap) {
     ThrowingVariant rhs = ExpectedThrower();
     EXPECT_TRUE(MakeExceptionSafetyTester()
                     .WithInitialValue(WithCopyNoThrow())
-                    .WithInvariants(CheckInvariants)
+                    .WithContracts(VariantInvariants)
                     .Test([&](ThrowingVariant* lhs) {
                       auto copy = rhs;
                       lhs->swap(copy);
@@ -496,7 +496,7 @@ TEST(VariantExceptionSafetyTest, Swap) {
     ThrowingVariant rhs = ExpectedThrower();
     EXPECT_TRUE(MakeExceptionSafetyTester()
                     .WithInitialValue(WithCopyNoThrow())
-                    .WithInvariants(CheckInvariants)
+                    .WithContracts(VariantInvariants)
                     .Test([&](ThrowingVariant* lhs) {
                       auto copy = rhs;
                       copy.swap(*lhs);