Back out "[folly] more ConcurrentHashMap deletion tests"

Summary:
Original commit changeset: bee63b3f597d.

Original revision is breaking integration tests by failing with the SIGSEGV in operator++, please check D6993857 for more details.

Reviewed By: anshulverma

Differential Revision: D7051998

fbshipit-source-id: e5cfbb22aee5f5ec9871a9a34bb27eb5b0036d1b

folly/concurrency/ConcurrentHashMap.h

@@ -444,17 +444,13 @@ class ConcurrentHashMap {
     void next() {
       while (it_ == parent_->ensureSegment(segment_)->cend() &&
              segment_ < parent_->NumShards) {
-        SegmentT* seg{nullptr};
-        while (!seg) {
-          segment_++;
-          seg = parent_->segments_[segment_].load(std::memory_order_acquire);
-          if (segment_ < parent_->NumShards) {
-            if (!seg) {
-              continue;
-            }
-            it_ = seg->cbegin();
+        segment_++;
+        auto seg = parent_->segments_[segment_].load(std::memory_order_acquire);
+        if (segment_ < parent_->NumShards) {
+          if (!seg) {
+            continue;
           }
-          break;
+          it_ = seg->cbegin();
         }
       }
     }

folly/concurrency/detail/ConcurrentHashMap-detail.h

@@ -589,8 +589,6 @@ class alignas(64) ConcurrentHashMapSegment {
   // throw if hash or key_eq functions throw.
   void erase(Iterator& res, Iterator& pos) {
     erase_internal(pos->first, &res);
-    // Invalidate the iterator.
-    pos = cend();
   }
 
   void clear() {

folly/concurrency/test/ConcurrentHashMapTest.cpp

@@ -594,107 +594,25 @@ TEST(ConcurrentHashMap, RefcountTest) {
 }
 
 struct Wrapper {
-  explicit Wrapper(bool& del_) : del(del_) {}
+  Wrapper() = default;
   ~Wrapper() {
     del = true;
   }
 
-  bool& del;
+  static bool del;
 };
 
-TEST(ConcurrentHashMap, Deletion) {
-  bool del{false};
-
-  {
-    ConcurrentHashMap<int, std::shared_ptr<Wrapper>> map;
+bool Wrapper::del = false;
 
-    map.insert(0, std::make_shared<Wrapper>(del));
-  }
-
-  EXPECT_TRUE(del);
-}
-
-TEST(ConcurrentHashMap, DeletionWithErase) {
-  bool del{false};
+TEST(ConcurrentHashMap, Deletion) {
+  EXPECT_FALSE(Wrapper::del);
 
   {
     ConcurrentHashMap<int, std::shared_ptr<Wrapper>> map;
 
-    map.insert(0, std::make_shared<Wrapper>(del));
+    map.insert(0, std::make_shared<Wrapper>());
     map.erase(0);
   }
 
-  EXPECT_TRUE(del);
-}
-
-TEST(ConcurrentHashMap, DeletionWithIterator) {
-  bool del{false};
-
-  {
-    ConcurrentHashMap<int, std::shared_ptr<Wrapper>> map;
-
-    map.insert(0, std::make_shared<Wrapper>(del));
-    auto it = map.find(0);
-    map.erase(it);
-  }
-
-  EXPECT_TRUE(del);
-}
-
-TEST(ConcurrentHashMap, DeletionWithForLoop) {
-  bool del{false};
-
-  {
-    ConcurrentHashMap<int, std::shared_ptr<Wrapper>> map;
-
-    map.insert(0, std::make_shared<Wrapper>(del));
-    for (auto it = map.cbegin(); it != map.cend(); ++it) {
-      EXPECT_EQ(it->first, 0);
-    }
-  }
-
-  EXPECT_TRUE(del);
-}
-
-TEST(ConcurrentHashMap, DeletionMultiple) {
-  bool del1{false}, del2{false};
-
-  {
-    ConcurrentHashMap<int, std::shared_ptr<Wrapper>> map;
-
-    map.insert(0, std::make_shared<Wrapper>(del1));
-    map.insert(1, std::make_shared<Wrapper>(del2));
-  }
-
-  EXPECT_TRUE(del1);
-  EXPECT_TRUE(del2);
-}
-
-TEST(ConcurrentHashMap, DeletionAssigned) {
-  bool del1{false}, del2{false};
-
-  {
-    ConcurrentHashMap<int, std::shared_ptr<Wrapper>> map;
-
-    map.insert(0, std::make_shared<Wrapper>(del1));
-    map.insert_or_assign(0, std::make_shared<Wrapper>(del2));
-  }
-
-  EXPECT_TRUE(del1);
-  EXPECT_TRUE(del2);
-}
-
-TEST(ConcurrentHashMap, DeletionMultipleMaps) {
-  bool del1{false}, del2{false};
-
-  {
-    ConcurrentHashMap<int, std::shared_ptr<Wrapper>> map1;
-    ConcurrentHashMap<int, std::shared_ptr<Wrapper>> map2;
-
-    map1.insert(0, std::make_shared<Wrapper>(del1));
-    map2.insert(0, std::make_shared<Wrapper>(del2));
-  }
-
-  EXPECT_TRUE(del1);
-  EXPECT_TRUE(del2);
+  EXPECT_TRUE(Wrapper::del);
 }

folly/experimental/hazptr/hazptr-impl.h

@@ -702,7 +702,6 @@ FOLLY_ALWAYS_INLINE hazptr_array<M>::~hazptr_array() {
       auto count = tc.count();
       if ((M <= HAZPTR_TC_SIZE) && (count + M <= HAZPTR_TC_SIZE)) {
         for (size_t i = 0; i < M; ++i) {
-          h[i].reset();
           tc[count + i].hprec_ = h[i].hazptr_;
           HAZPTR_DEBUG_PRINT(i << " " << &h[i]);
           new (&h[i]) hazptr_holder(nullptr);