Merge remote-tracking branch 'namada/tiago/main/hotfix-prepare-propos…

…al' (#952) into maint-0.12

* namada/tiago/main/hotfix-prepare-proposal:
  changelog: add #952
  prepare_proposal: update comment to reflect hotfix
  prepare_proposal: use TxRecord struct on ABCI++ build
  Prioritize wrapper txs during proposal construction
  Hot fix PrepareProposal

.changelog/unreleased/bug-fixes/952-hotfix-prepare-proposal.md

@@ -0,0 +1,2 @@
+- Limit block space to under Tendermint's limit, and limit transactions included
+  in a block by their size. ([#952](https://github.com/anoma/namada/pull/952))

apps/src/lib/node/ledger/shell/prepare_proposal.rs

@@ -13,16 +13,24 @@ use crate::facade::tendermint_proto::abci::{tx_record::TxAction, TxRecord};
 use crate::node::ledger::shell::{process_tx, ShellMode};
 use crate::node::ledger::shims::abcipp_shim_types::shim::TxBytes;
 
+// TODO: remove this hard-coded value; Tendermint, and thus
+// Namada uses 20 MiB max block sizes by default; 16 MiB leaves
+// plenty of room for header data, evidence and protobuf serialization
+// overhead
+const MAX_PROPOSAL_SIZE: usize = 16 << 20;
+const HALF_MAX_PROPOSAL_SIZE: usize = MAX_PROPOSAL_SIZE / 2;
+
 impl<D, H> Shell<D, H>
 where
     D: DB + for<'iter> DBIter<'iter> + Sync + 'static,
     H: StorageHasher + Sync + 'static,
 {
     /// Begin a new block.
     ///
-    /// We include half of the new wrapper txs given to us from the mempool
-    /// by tendermint. The rest of the block is filled with decryptions
-    /// of the wrapper txs from the previously committed block.
+    /// We fill half the block space with new wrapper txs given to us
+    /// from the mempool by tendermint. The rest of the block is filled
+    /// with decryptions of the wrapper txs from the previously
+    /// committed block.
     ///
     /// INVARIANT: Any changes applied in this method must be reverted if
     /// the proposal is rejected (unless we can simply overwrite
@@ -38,12 +46,11 @@ where
             // TODO: Craft the Ethereum state update tx
             // filter in half of the new txs from Tendermint, only keeping
             // wrappers
-            let number_of_new_txs = 1 + req.txs.len() / 2;
+            let mut total_proposal_size = 0;
             #[cfg(feature = "abcipp")]
             let mut txs: Vec<TxRecord> = req
                 .txs
                 .into_iter()
-                .take(number_of_new_txs)
                 .map(|tx_bytes| {
                     if let Ok(Ok(TxType::Wrapper(_))) =
                         Tx::try_from(tx_bytes.as_slice()).map(process_tx)
@@ -53,12 +60,22 @@ where
                         record::remove(tx_bytes)
                     }
                 })
+                .take_while(|tx_record| {
+                    let new_size = total_proposal_size + tx_record.tx.len();
+                    if new_size > HALF_MAX_PROPOSAL_SIZE
+                        || tx_record.action != TxAction::Unmodified as i32
+                    {
+                        false
+                    } else {
+                        total_proposal_size = new_size;
+                        true
+                    }
+                })
                 .collect();
             #[cfg(not(feature = "abcipp"))]
             let mut txs: Vec<TxBytes> = req
                 .txs
                 .into_iter()
-                .take(number_of_new_txs)
                 .filter_map(|tx_bytes| {
                     if let Ok(Ok(TxType::Wrapper(_))) =
                         Tx::try_from(tx_bytes.as_slice()).map(process_tx)
@@ -68,6 +85,15 @@ where
                         None
                     }
                 })
+                .take_while(|tx_bytes| {
+                    let new_size = total_proposal_size + tx_bytes.len();
+                    if new_size > HALF_MAX_PROPOSAL_SIZE {
+                        false
+                    } else {
+                        total_proposal_size = new_size;
+                        true
+                    }
+                })
                 .collect();
 
             // decrypt the wrapper txs included in the previous block