after the hard fork, disallow block references

Author: arvidn

chia/consensus/block_body_validation.py

@@ -341,10 +341,14 @@ async def validate_block_body(
     #     the generator ref list for this block (or 'one' bytes [0x01] if no generator)
     # 8b. The generator ref list length must be less than or equal to MAX_GENERATOR_REF_LIST_SIZE entries
     # 8c. The generator ref list must not point to a height >= this block's height
-    if block.transactions_generator_ref_list in (None, []):
+    if block.transactions_generator_ref_list == []:
         if block.transactions_info.generator_refs_root != bytes([1] * 32):
             return Err.INVALID_TRANSACTIONS_GENERATOR_REFS_ROOT
     else:
+        # With hard fork 2 we ban transactions_generator_ref_list.
+        if prev_transaction_block_height >= constants.HARD_FORK2_HEIGHT:
+            return Err.TOO_MANY_GENERATOR_REFS
+
         # If we have a generator reference list, we must have a generator
         if block.transactions_generator is None:
             return Err.INVALID_TRANSACTIONS_GENERATOR_REFS_ROOT

chia/simulator/block_tools.py

@@ -385,6 +385,10 @@ def setup_new_gen(
         transaction_data: Optional[SpendBundle],
         block_refs: list[uint32],
     ) -> Optional[NewBlockGenerator]:
+        if prev_tx_height >= self.constants.HARD_FORK2_HEIGHT:
+            assert block_refs == [], "block references are not allowed after hard fork 2"
+            dummy_block_references = False
+
         # we don't know if the new block will be a transaction
         # block or not, so even though we prepare a block
         # generator, we can't update our state (like,