Use `NonZeroU32` for all `min_confirmations` values.

zcash_client_backend/CHANGELOG.md

@@ -30,6 +30,7 @@ and this library adheres to Rust's notion of
     wallet states where the full note plaintext is not available.
   - `WalletRead::get_nullifiers` has been renamed to `WalletRead::get_sapling_nullifiers`
     and its signature has changed; it now subsumes the removed `WalletRead::get_all_nullifiers`.
+  - `WalletRead::get_target_and_anchor_heights` now takes its argument as a `NonZeroU32`
   - `chain::scan_cached_blocks` now takes a `from_height` argument that
     permits the caller to control the starting position of the scan range.
   - A new `CommitmentTree` variant has been added to `data_api::error::Error`
@@ -38,6 +39,11 @@ and this library adheres to Rust's notion of
     implemented for the type passed to them for the `wallet_db` parameter.
   - `data_api::wallet::create_proposed_transaction` now takes an additional 
     `min_confirmations` argument.
+  - `data_api::wallet::{spend, create_spend_to_address, shield_transparent_funds, 
+    propose_transfer, propose_shielding, create_proposed_transaction}` now take their
+    respective `min_confirmations` arguments as `NonZeroU32`
+  - `data_api::wallet::input_selection::InputSelector::{propose_transaction, propose_shielding}`
+    now take their respective `min_confirmations` arguments as `NonZeroU32`
   - A new `Sync` variant has been added to `data_api::chain::error::Error`.
   - A new `SyncRequired` variant has been added to `data_api::wallet::input_selection::InputSelectorError`.
 - `zcash_client_backend::wallet`:

zcash_client_backend/src/data_api.rs

@@ -2,6 +2,7 @@
 
 use std::collections::HashMap;
 use std::fmt::Debug;
+use std::num::NonZeroU32;
 use std::{cmp, ops::Range};
 
 use incrementalmerkletree::Retention;
@@ -97,7 +98,7 @@ pub trait WalletRead {
     /// This will return `Ok(None)` if no block data is present in the database.
     fn get_target_and_anchor_heights(
         &self,
-        min_confirmations: u32,
+        min_confirmations: NonZeroU32,
     ) -> Result<Option<(BlockHeight, BlockHeight)>, Self::Error> {
         self.block_height_extrema().map(|heights| {
             heights.map(|(min_height, max_height)| {
@@ -106,7 +107,7 @@ pub trait WalletRead {
                 // Select an anchor min_confirmations back from the target block,
                 // unless that would be before the earliest block we have.
                 let anchor_height = BlockHeight::from(cmp::max(
-                    u32::from(target_height).saturating_sub(min_confirmations),
+                    u32::from(target_height).saturating_sub(min_confirmations.into()),
                     u32::from(min_height),
                 ));
 

zcash_client_backend/src/data_api/wallet.rs

@@ -1,4 +1,4 @@
-use std::convert::Infallible;
+use std::{convert::Infallible, num::NonZeroU32};
 use std::fmt::Debug;
 
 use shardtree::{ShardStore, ShardTree, ShardTreeError};
@@ -122,10 +122,6 @@ where
 ///   spent. A value of 10 confirmations is recommended and 0-conf transactions are
 ///   not supported.
 ///
-/// # Panics
-///
-/// Panics if `min_confirmations == 0`; 0-conf transactions are not supported.
-///
 /// # Examples
 ///
 /// ```
@@ -203,7 +199,7 @@ pub fn create_spend_to_address<DbT, ParamsT>(
     amount: Amount,
     memo: Option<MemoBytes>,
     ovk_policy: OvkPolicy,
-    min_confirmations: u32,
+    min_confirmations: NonZeroU32,
 ) -> Result<
     DbT::TxRef,
     Error<
@@ -292,7 +288,8 @@ where
 ///   can allow the sender to view the resulting notes on the blockchain.
 /// * `min_confirmations`: The minimum number of confirmations that a previously
 ///   received note must have in the blockchain in order to be considered for being
-///   spent. A value of 10 confirmations is recommended.
+///   spent. A value of 10 confirmations is recommended and 0-conf transactions are
+///   not supported.
 ///
 /// [`sapling::TxProver`]: zcash_primitives::sapling::prover::TxProver
 #[allow(clippy::too_many_arguments)]
@@ -305,7 +302,7 @@ pub fn spend<DbT, ParamsT, InputsT>(
     usk: &UnifiedSpendingKey,
     request: zip321::TransactionRequest,
     ovk_policy: OvkPolicy,
-    min_confirmations: u32,
+    min_confirmations: NonZeroU32,
 ) -> Result<
     DbT::TxRef,
     Error<
@@ -323,10 +320,6 @@ where
     ParamsT: consensus::Parameters + Clone,
     InputsT: InputSelector<DataSource = DbT>,
 {
-    assert!(
-        min_confirmations > 0,
-        "zero-conf transactions are not supported"
-    );
     let account = wallet_db
         .get_account_for_ufvk(&usk.to_unified_full_viewing_key())
         .map_err(Error::DataSource)?
@@ -364,7 +357,7 @@ pub fn propose_transfer<DbT, ParamsT, InputsT, CommitmentTreeErrT>(
     spend_from_account: AccountId,
     input_selector: &InputsT,
     request: zip321::TransactionRequest,
-    min_confirmations: u32,
+    min_confirmations: NonZeroU32,
 ) -> Result<
     Proposal<InputsT::FeeRule, DbT::NoteRef>,
     Error<
@@ -381,10 +374,6 @@ where
     ParamsT: consensus::Parameters + Clone,
     InputsT: InputSelector<DataSource = DbT>,
 {
-    assert!(
-        min_confirmations > 0,
-        "zero-conf transactions are not supported"
-    );
     input_selector
         .propose_transaction(
             params,
@@ -405,7 +394,7 @@ pub fn propose_shielding<DbT, ParamsT, InputsT, CommitmentTreeErrT>(
     input_selector: &InputsT,
     shielding_threshold: NonNegativeAmount,
     from_addrs: &[TransparentAddress],
-    min_confirmations: u32,
+    min_confirmations: NonZeroU32
 ) -> Result<
     Proposal<InputsT::FeeRule, DbT::NoteRef>,
     Error<
@@ -422,10 +411,6 @@ where
     DbT::NoteRef: Copy + Eq + Ord,
     InputsT: InputSelector<DataSource = DbT>,
 {
-    assert!(
-        min_confirmations > 0,
-        "zero-conf transactions are not supported"
-    );
     input_selector
         .propose_shielding(
             params,
@@ -451,7 +436,7 @@ pub fn create_proposed_transaction<DbT, ParamsT, InputsErrT, FeeRuleT>(
     usk: &UnifiedSpendingKey,
     ovk_policy: OvkPolicy,
     proposal: Proposal<FeeRuleT, DbT::NoteRef>,
-    min_confirmations: u32,
+    min_confirmations: NonZeroU32,
     change_memo: Option<MemoBytes>,
 ) -> Result<
     DbT::TxRef,
@@ -470,10 +455,6 @@ where
     ParamsT: consensus::Parameters + Clone,
     FeeRuleT: FeeRule,
 {
-    assert!(
-        min_confirmations > 0,
-        "zero-conf transactions are not supported"
-    );
     let account = wallet_db
         .get_account_for_ufvk(&usk.to_unified_full_viewing_key())
         .map_err(Error::DataSource)?
@@ -516,8 +497,7 @@ where
                 selected,
                 usk.sapling(),
                 &dfvk,
-                usize::try_from(min_confirmations - 1)
+                usize::try_from(u32::from(min_confirmations) - 1).unwrap()
-                    .expect("min_confirmations should never be anywhere close to usize::MAX"),
             )?
             .ok_or(Error::NoteMismatch(selected.note_id))?;
 
@@ -711,8 +691,9 @@ where
 ///   to the wallet that the wallet can use to improve how it represents those
 ///   shielding transactions to the user.
 /// * `min_confirmations`: The minimum number of confirmations that a previously
-///   received UTXO must have in the blockchain in order to be considered for being
+///   received note must have in the blockchain in order to be considered for being
-///   spent.
+///   spent. A value of 10 confirmations is recommended and 0-conf transactions are
+///   not supported.
 ///
 /// [`sapling::TxProver`]: zcash_primitives::sapling::prover::TxProver
 #[cfg(feature = "transparent-inputs")]
@@ -727,7 +708,7 @@ pub fn shield_transparent_funds<DbT, ParamsT, InputsT>(
     usk: &UnifiedSpendingKey,
     from_addrs: &[TransparentAddress],
     memo: &MemoBytes,
-    min_confirmations: u32,
+    min_confirmations: NonZeroU32,
 ) -> Result<
     DbT::TxRef,
     Error<

zcash_client_backend/src/data_api/wallet/input_selection.rs

@@ -2,6 +2,7 @@
 
 use core::marker::PhantomData;
 use std::fmt;
+use std::num::NonZeroU32;
 use std::{collections::BTreeSet, fmt::Debug};
 
 use zcash_primitives::{
@@ -180,7 +181,7 @@ pub trait InputSelector {
         wallet_db: &Self::DataSource,
         account: AccountId,
         transaction_request: TransactionRequest,
-        min_confirmations: u32,
+        min_confirmations: NonZeroU32,
     ) -> Result<
         Proposal<Self::FeeRule, <<Self as InputSelector>::DataSource as WalletRead>::NoteRef>,
         InputSelectorError<<<Self as InputSelector>::DataSource as WalletRead>::Error, Self::Error>,
@@ -204,7 +205,7 @@ pub trait InputSelector {
         wallet_db: &Self::DataSource,
         shielding_threshold: NonNegativeAmount,
         source_addrs: &[TransparentAddress],
-        min_confirmations: u32,
+        min_confirmations: NonZeroU32,
     ) -> Result<
         Proposal<Self::FeeRule, <<Self as InputSelector>::DataSource as WalletRead>::NoteRef>,
         InputSelectorError<<<Self as InputSelector>::DataSource as WalletRead>::Error, Self::Error>,
@@ -324,7 +325,7 @@ where
         wallet_db: &Self::DataSource,
         account: AccountId,
         transaction_request: TransactionRequest,
-        min_confirmations: u32,
+        min_confirmations: NonZeroU32,
     ) -> Result<Proposal<Self::FeeRule, DbT::NoteRef>, InputSelectorError<DbT::Error, Self::Error>>
     where
         ParamsT: consensus::Parameters,
@@ -442,7 +443,7 @@ where
         wallet_db: &Self::DataSource,
         shielding_threshold: NonNegativeAmount,
         source_addrs: &[TransparentAddress],
-        min_confirmations: u32,
+        min_confirmations: NonZeroU32,
     ) -> Result<Proposal<Self::FeeRule, DbT::NoteRef>, InputSelectorError<DbT::Error, Self::Error>>
     where
         ParamsT: consensus::Parameters,

zcash_client_sqlite/src/chain.rs

@@ -265,6 +265,8 @@ where
 #[cfg(test)]
 #[allow(deprecated)]
 mod tests {
+    use std::num::NonZeroU32;
+
     use secrecy::Secret;
     use tempfile::NamedTempFile;
 
@@ -681,7 +683,7 @@ mod tests {
                 &usk,
                 req,
                 OvkPolicy::Sender,
-                1,
+                NonZeroU32::new(1).unwrap(),
             ),
             Ok(_)
         );

zcash_client_sqlite/src/wallet.rs

@@ -544,6 +544,8 @@ pub(crate) fn block_height_extrema(
 pub(crate) fn fully_scanned_height(
     conn: &rusqlite::Connection,
 ) -> Result<Option<(BlockHeight, CommitmentTreeMeta)>, SqliteClientError> {
+    // FIXME: this will need to be rewritten once out-of-order scan range suggestion
+    // is implemented.
     let res_opt = conn
         .query_row(
             "SELECT height, sapling_commitment_tree_size, sapling_tree
@@ -1155,6 +1157,8 @@ pub(crate) fn put_sent_output<P: consensus::Parameters>(
 
 #[cfg(test)]
 mod tests {
+    use std::num::NonZeroU32;
+
     use secrecy::Secret;
     use tempfile::NamedTempFile;
 
@@ -1197,7 +1201,12 @@ mod tests {
         );
 
         // We can't get an anchor height, as we have not scanned any blocks.
-        assert_eq!(db_data.get_target_and_anchor_heights(10).unwrap(), None);
+        assert_eq!(
+            db_data
+                .get_target_and_anchor_heights(NonZeroU32::new(10).unwrap())
+                .unwrap(),
+            None
+        );
 
         // An invalid account has zero balance
         assert_matches!(

zcash_client_sqlite/src/wallet/sapling.rs

@@ -367,6 +367,8 @@ pub(crate) fn put_received_note<T: ReceivedSaplingOutput>(
 #[cfg(test)]
 #[allow(deprecated)]
 pub(crate) mod tests {
+    use std::num::NonZeroU32;
+
     use rusqlite::Connection;
     use secrecy::Secret;
     use tempfile::NamedTempFile;
@@ -461,7 +463,7 @@ pub(crate) mod tests {
                 Amount::from_u64(1).unwrap(),
                 None,
                 OvkPolicy::Sender,
-                1,
+                NonZeroU32::new(1).unwrap(),
             ),
             Err(data_api::error::Error::KeyNotRecognized)
         );
@@ -490,7 +492,7 @@ pub(crate) mod tests {
                 Amount::from_u64(1).unwrap(),
                 None,
                 OvkPolicy::Sender,
-                1,
+                NonZeroU32::new(1).unwrap(),
             ),
             Err(data_api::error::Error::ScanRequired)
         );
@@ -533,7 +535,7 @@ pub(crate) mod tests {
                 Amount::from_u64(1).unwrap(),
                 None,
                 OvkPolicy::Sender,
-                1,
+                NonZeroU32::new(1).unwrap(),
             ),
             Err(data_api::error::Error::InsufficientFunds {
                 available,
@@ -572,7 +574,10 @@ pub(crate) mod tests {
         scan_cached_blocks(&tests::network(), &db_cache, &mut db_data, None, None).unwrap();
 
         // Verified balance matches total balance
-        let (_, anchor_height) = db_data.get_target_and_anchor_heights(10).unwrap().unwrap();
+        let (_, anchor_height) = db_data
+            .get_target_and_anchor_heights(NonZeroU32::new(10).unwrap())
+            .unwrap()
+            .unwrap();
         assert_eq!(
             get_balance(&db_data.conn, AccountId::from(0)).unwrap(),
             value
@@ -595,7 +600,10 @@ pub(crate) mod tests {
         scan_cached_blocks(&tests::network(), &db_cache, &mut db_data, None, None).unwrap();
 
         // Verified balance does not include the second note
-        let (_, anchor_height2) = db_data.get_target_and_anchor_heights(10).unwrap().unwrap();
+        let (_, anchor_height2) = db_data
+            .get_target_and_anchor_heights(NonZeroU32::new(10).unwrap())
+            .unwrap()
+            .unwrap();
         assert_eq!(
             get_balance(&db_data.conn, AccountId::from(0)).unwrap(),
             (value + value).unwrap()
@@ -618,7 +626,7 @@ pub(crate) mod tests {
                 Amount::from_u64(70000).unwrap(),
                 None,
                 OvkPolicy::Sender,
-                10,
+                NonZeroU32::new(10).unwrap(),
             ),
             Err(data_api::error::Error::InsufficientFunds {
                 available,
@@ -654,7 +662,7 @@ pub(crate) mod tests {
                 Amount::from_u64(70000).unwrap(),
                 None,
                 OvkPolicy::Sender,
-                10,
+                NonZeroU32::new(10).unwrap(),
             ),
             Err(data_api::error::Error::InsufficientFunds {
                 available,
@@ -687,7 +695,7 @@ pub(crate) mod tests {
                 Amount::from_u64(70000).unwrap(),
                 None,
                 OvkPolicy::Sender,
-                10,
+                NonZeroU32::new(10).unwrap(),
             ),
             Ok(_)
         );
@@ -738,7 +746,7 @@ pub(crate) mod tests {
                 Amount::from_u64(15000).unwrap(),
                 None,
                 OvkPolicy::Sender,
-                1,
+                NonZeroU32::new(1).unwrap(),
             ),
             Ok(_)
         );
@@ -754,7 +762,7 @@ pub(crate) mod tests {
                 Amount::from_u64(2000).unwrap(),
                 None,
                 OvkPolicy::Sender,
-                1,
+                NonZeroU32::new(1).unwrap(),
             ),
             Err(data_api::error::Error::InsufficientFunds {
                 available,
@@ -789,7 +797,7 @@ pub(crate) mod tests {
                 Amount::from_u64(2000).unwrap(),
                 None,
                 OvkPolicy::Sender,
-                1,
+                NonZeroU32::new(1).unwrap(),
             ),
             Err(data_api::error::Error::InsufficientFunds {
                 available,
@@ -820,7 +828,7 @@ pub(crate) mod tests {
             Amount::from_u64(2000).unwrap(),
             None,
             OvkPolicy::Sender,
-            1,
+            NonZeroU32::new(1).unwrap(),
         )
         .unwrap();
     }
@@ -872,7 +880,7 @@ pub(crate) mod tests {
                 Amount::from_u64(15000).unwrap(),
                 None,
                 ovk_policy,
-                1,
+                NonZeroU32::new(1).unwrap(),
             )
             .unwrap();
 
@@ -960,7 +968,10 @@ pub(crate) mod tests {
         scan_cached_blocks(&tests::network(), &db_cache, &mut db_data, None, None).unwrap();
 
         // Verified balance matches total balance
-        let (_, anchor_height) = db_data.get_target_and_anchor_heights(1).unwrap().unwrap();
+        let (_, anchor_height) = db_data
+            .get_target_and_anchor_heights(NonZeroU32::new(1).unwrap())
+            .unwrap()
+            .unwrap();
         assert_eq!(
             get_balance(&db_data.conn, AccountId::from(0)).unwrap(),
             value
@@ -981,7 +992,7 @@ pub(crate) mod tests {
                 Amount::from_u64(50000).unwrap(),
                 None,
                 OvkPolicy::Sender,
-                1,
+                NonZeroU32::new(1).unwrap(),
             ),
             Ok(_)
         );
@@ -1016,7 +1027,10 @@ pub(crate) mod tests {
         scan_cached_blocks(&tests::network(), &db_cache, &mut db_data, None, None).unwrap();
 
         // Verified balance matches total balance
-        let (_, anchor_height) = db_data.get_target_and_anchor_heights(10).unwrap().unwrap();
+        let (_, anchor_height) = db_data
+            .get_target_and_anchor_heights(NonZeroU32::new(10).unwrap())
+            .unwrap()
+            .unwrap();
         assert_eq!(
             get_balance(&db_data.conn, AccountId::from(0)).unwrap(),
             value
@@ -1037,7 +1051,7 @@ pub(crate) mod tests {
                 Amount::from_u64(50000).unwrap(),
                 None,
                 OvkPolicy::Sender,
-                1,
+                NonZeroU32::new(1).unwrap(),
             ),
             Ok(_)
         );
@@ -1086,7 +1100,10 @@ pub(crate) mod tests {
 
         // Verified balance matches total balance
         let total = Amount::from_u64(60000).unwrap();
-        let (_, anchor_height) = db_data.get_target_and_anchor_heights(1).unwrap().unwrap();
+        let (_, anchor_height) = db_data
+            .get_target_and_anchor_heights(NonZeroU32::new(1).unwrap())
+            .unwrap()
+            .unwrap();
         assert_eq!(
             get_balance(&db_data.conn, AccountId::from(0)).unwrap(),
             total
@@ -1121,7 +1138,7 @@ pub(crate) mod tests {
                 &usk,
                 req,
                 OvkPolicy::Sender,
-                1,
+                NonZeroU32::new(1).unwrap(),
             ),
             Err(Error::InsufficientFunds { available, required })
                 if available == Amount::from_u64(51000).unwrap()
@@ -1149,7 +1166,7 @@ pub(crate) mod tests {
                 &usk,
                 req,
                 OvkPolicy::Sender,
-                1,
+                NonZeroU32::new(1).unwrap(),
             ),
             Ok(_)
         );
@@ -1213,7 +1230,7 @@ pub(crate) mod tests {
                 &usk,
                 &[*taddr],
                 &MemoBytes::empty(),
-                1
+                NonZeroU32::new(1).unwrap()
             ),
             Ok(_)
         );