Check FRESH validity in CCoinsViewCache::BatchWrite

ryanofsky · random-zebra · commit 03031a5ff7be · 2020-08-12T12:00:32.000+02:00
diff --git a/src/coins.cpp b/src/coins.cpp
@@ -213,6 +213,13 @@ bool CCoinsViewCache::BatchWrite(CCoinsMap& mapCoins, const uint256& hashBlockIn
                         entry.flags |= CCoinsCacheEntry::FRESH;
                 }
             } else {
+                // Assert that the child cache entry was not marked FRESH if the
+                // parent cache entry has unspent outputs. If this ever happens,
+                // it means the FRESH flag was misapplied and there is a logic
+                // error in the calling code.
+                if ((it->second.flags & CCoinsCacheEntry::FRESH) && !itUs->second.coins.IsPruned())
+                    throw std::logic_error("FRESH flag misapplied to cache entry for base transaction with spendable outputs");
+
                 // Found the entry in the parent cache
                 if ((itUs->second.flags & CCoinsCacheEntry::FRESH) && it->second.coins.IsPruned()) {
                     // The grandparent does not have an entry, and the child is
diff --git a/src/test/coins_tests.cpp b/src/test/coins_tests.cpp
@@ -742,12 +742,18 @@ BOOST_AUTO_TEST_CASE(ccoins_modify_new)
 void CheckWriteCoins(CAmount parent_value, CAmount child_value, CAmount expected_value, char parent_flags, char child_flags, char expected_flags)
 {
     SingleEntryCacheTest test(ABSENT, parent_value, parent_flags);
-    WriteCoinsViewEntry(test.cache, child_value, child_flags);
-    test.cache.SelfTest();
 
     CAmount result_value;
     char result_flags;
-    GetCoinsMapEntry(test.cache.map(), result_value, result_flags);
+    try {
+        WriteCoinsViewEntry(test.cache, child_value, child_flags);
+        test.cache.SelfTest();
+        GetCoinsMapEntry(test.cache.map(), result_value, result_flags);
+    } catch (std::logic_error& e) {
+        result_value = FAIL;
+        result_flags = NO_ENTRY;
+    }
+
     BOOST_CHECK_EQUAL(result_value, expected_value);
     BOOST_CHECK_EQUAL(result_flags, expected_flags);
 }
@@ -791,21 +797,21 @@ BOOST_AUTO_TEST_CASE(ccoins_write)
     CheckWriteCoins(VALUE1, ABSENT, VALUE1, DIRTY      , NO_ENTRY   , DIRTY      );
     CheckWriteCoins(VALUE1, ABSENT, VALUE1, DIRTY|FRESH, NO_ENTRY   , DIRTY|FRESH);
     CheckWriteCoins(VALUE1, PRUNED, PRUNED, 0          , DIRTY      , DIRTY      );
-    CheckWriteCoins(VALUE1, PRUNED, PRUNED, 0          , DIRTY|FRESH, DIRTY      );
+    CheckWriteCoins(VALUE1, PRUNED, FAIL  , 0          , DIRTY|FRESH, NO_ENTRY   );
     CheckWriteCoins(VALUE1, PRUNED, ABSENT, FRESH      , DIRTY      , NO_ENTRY   );
-    CheckWriteCoins(VALUE1, PRUNED, ABSENT, FRESH      , DIRTY|FRESH, NO_ENTRY   );
+    CheckWriteCoins(VALUE1, PRUNED, FAIL  , FRESH      , DIRTY|FRESH, NO_ENTRY   );
     CheckWriteCoins(VALUE1, PRUNED, PRUNED, DIRTY      , DIRTY      , DIRTY      );
-    CheckWriteCoins(VALUE1, PRUNED, PRUNED, DIRTY      , DIRTY|FRESH, DIRTY      );
+    CheckWriteCoins(VALUE1, PRUNED, FAIL  , DIRTY      , DIRTY|FRESH, NO_ENTRY   );
     CheckWriteCoins(VALUE1, PRUNED, ABSENT, DIRTY|FRESH, DIRTY      , NO_ENTRY   );
-    CheckWriteCoins(VALUE1, PRUNED, ABSENT, DIRTY|FRESH, DIRTY|FRESH, NO_ENTRY   );
+    CheckWriteCoins(VALUE1, PRUNED, FAIL  , DIRTY|FRESH, DIRTY|FRESH, NO_ENTRY   );
     CheckWriteCoins(VALUE1, VALUE2, VALUE2, 0          , DIRTY      , DIRTY      );
-    CheckWriteCoins(VALUE1, VALUE2, VALUE2, 0          , DIRTY|FRESH, DIRTY      );
+    CheckWriteCoins(VALUE1, VALUE2, FAIL  , 0          , DIRTY|FRESH, NO_ENTRY   );
     CheckWriteCoins(VALUE1, VALUE2, VALUE2, FRESH      , DIRTY      , DIRTY|FRESH);
-    CheckWriteCoins(VALUE1, VALUE2, VALUE2, FRESH      , DIRTY|FRESH, DIRTY|FRESH);
+    CheckWriteCoins(VALUE1, VALUE2, FAIL  , FRESH      , DIRTY|FRESH, NO_ENTRY   );
     CheckWriteCoins(VALUE1, VALUE2, VALUE2, DIRTY      , DIRTY      , DIRTY      );
-    CheckWriteCoins(VALUE1, VALUE2, VALUE2, DIRTY      , DIRTY|FRESH, DIRTY      );
+    CheckWriteCoins(VALUE1, VALUE2, FAIL  , DIRTY      , DIRTY|FRESH, NO_ENTRY   );
     CheckWriteCoins(VALUE1, VALUE2, VALUE2, DIRTY|FRESH, DIRTY      , DIRTY|FRESH);
-    CheckWriteCoins(VALUE1, VALUE2, VALUE2, DIRTY|FRESH, DIRTY|FRESH, DIRTY|FRESH);
+    CheckWriteCoins(VALUE1, VALUE2, FAIL  , DIRTY|FRESH, DIRTY|FRESH, NO_ENTRY   );
 
     // The checks above omit cases where the child flags are not DIRTY, since
     // they would be too repetitive (the parent cache is never updated in these
