[packages] add sanity checks for package vs mempool limits

Author: glozow

src/validation.h

@@ -60,6 +60,16 @@ static const unsigned int DEFAULT_ANCESTOR_SIZE_LIMIT = 101;
 static const unsigned int DEFAULT_DESCENDANT_LIMIT = 25;
 /** Default for -limitdescendantsize, maximum kilobytes of in-mempool descendants */
 static const unsigned int DEFAULT_DESCENDANT_SIZE_LIMIT = 101;
+
+// If a package is submitted, it must be within the mempool's ancestor/descendant limits. Since a
+// submitted package must be child-with-unconfirmed-parents (all of the transactions are an ancestor
+// of the child), package limits are ultimately bounded by mempool package limits. Ensure that the
+// defaults reflect this constraint.
+static_assert(DEFAULT_DESCENDANT_LIMIT >= MAX_PACKAGE_COUNT);
+static_assert(DEFAULT_ANCESTOR_LIMIT >= MAX_PACKAGE_COUNT);
+static_assert(DEFAULT_ANCESTOR_SIZE_LIMIT >= MAX_PACKAGE_SIZE);
+static_assert(DEFAULT_DESCENDANT_SIZE_LIMIT >= MAX_PACKAGE_SIZE);
+
 /** Default for -mempoolexpiry, expiration time for mempool transactions in hours */
 static const unsigned int DEFAULT_MEMPOOL_EXPIRY = 336;
 /** Maximum number of dedicated script-checking threads allowed */