Remove a check from setOldestVersion

ConflictSet.cpp

@@ -1554,15 +1554,14 @@ struct __attribute__((visibility("hidden"))) ConflictSet::Impl {
         // Any transaction prev would have prevented from committing is
         // going to fail with TooOld anyway.
 
-        // We still need to make sure that we don't introduce false positives by
-        // just removing it though.
-        if (n->entry.rangeVersion <= oldestVersion) {
+        // There's no way to insert a range such that range version of the right
+        // node is greater than the point version of the left node
+        assert(n->entry.rangeVersion <= oldestVersion);
         prev->entryPresent = false;
         if (prev->numChildren == 0 && prev->parent != nullptr) {
           eraseChild(prev->parent, prev->parentsIndex);
         }
       }
-      }
 
       prev = n;
     }

Internal.h

@@ -427,6 +427,7 @@ struct ReferenceImpl {
   }
 
   void setOldestVersion(int64_t oldestVersion) {
+    assert(oldestVersion >= oldestVersion);
     this->oldestVersion = oldestVersion;
   }
 
@@ -569,6 +570,11 @@ template <class ConflictSetImpl> struct TestDriver {
       CALLGRIND_STOP_INSTRUMENTATION;
 #endif
       refImpl.addWrites(writes, numPointWrites + numRangeWrites);
+
+      oldestVersion = std::max<int64_t>(writeVersion - arbitrary.bounded(10),
+                                        oldestVersion);
+      cs.setOldestVersion(oldestVersion);
+      refImpl.setOldestVersion(oldestVersion);
     }
     {
       int numPointReads = arbitrary.bounded(100);
@@ -659,9 +665,6 @@ template <class ConflictSetImpl> struct TestDriver {
         }
       }
     }
-    oldestVersion += arbitrary.bounded(2);
-    cs.setOldestVersion(oldestVersion);
-    refImpl.setOldestVersion(oldestVersion);
     return false;
   }
 };