address review comments

Author: arvidn

chia/full_node/weight_proof.py

@@ -1367,14 +1367,17 @@ def __validate_pospace(
     # validate proof of space
     assert sub_slot_data.proof_of_space is not None
 
+    # when sampling blocks as part of weight proof validation, the previous
+    # transaction height is a conservative estimate, since we don't have direct
+    # access to it.
     required_iters = validate_pospace_and_get_required_iters(
         constants,
         sub_slot_data.proof_of_space,
         challenge,
         cc_sp_hash,
         height,
         curr_diff,
-        uint32(0),  # prev_tx_block(blocks, prev_b), todo need to get height of prev tx block somehow here
+        uint32(max(0, height - constants.MAX_SUB_SLOT_BLOCKS)),
     )
     if required_iters is None:
         log.error("could not verify proof of space")

chia/types/blockchain_format/proof_of_space.py

@@ -109,8 +109,6 @@ def is_v1_phased_out(
     return proof_value > epoch_counter
 
 
-# TODO: the "height" parameter is a bit suspect. It can probably be removed in
-# favor of prev_transaction_block_height
 def verify_and_get_quality_string(
     pos: ProofOfSpace,
     constants: ConsensusConstants,
@@ -123,6 +121,7 @@ def verify_and_get_quality_string(
     plot_size = pos.size()
 
     if plot_size.size_v1 is not None and is_v1_phased_out(pos.proof, prev_transaction_block_height, constants):
+        log.info("v1 proof has been phased-out and is no longer valid")
         return None
 
     # Exactly one of (pool_public_key, pool_contract_puzzle_hash) must not be None