zcash_client_sqlite: Return a balance for every account from `get_wallet_summary`

Fixes #948

zcash_client_backend/src/data_api.rs

@@ -102,6 +102,12 @@ pub struct AccountBalance {
 }
 
 impl AccountBalance {
+    /// The [`Balance`] value having zero values for all its fields.
+    pub const ZERO: Self = Self {
+        sapling_balance: Balance::ZERO,
+        unshielded: NonNegativeAmount::ZERO,
+    };
+
     /// Returns the total value of funds belonging to the account.
     pub fn total(&self) -> NonNegativeAmount {
         (self.sapling_balance.total() + self.unshielded)

zcash_client_sqlite/src/wallet.rs

@@ -73,7 +73,7 @@ use std::convert::TryFrom;
 use std::io::{self, Cursor};
 use std::num::NonZeroU32;
 use tracing::debug;
-use zcash_client_backend::data_api::{AccountBalance, Balance, Ratio, WalletSummary};
+use zcash_client_backend::data_api::{AccountBalance, Ratio, WalletSummary};
 use zcash_primitives::transaction::components::amount::NonNegativeAmount;
 
 use zcash_client_backend::data_api::{
@@ -626,6 +626,15 @@ pub(crate) fn get_wallet_summary(
         |row| row.get::<_, bool>(0),
     )?;
 
+    let mut stmt_accounts = conn.prepare_cached("SELECT account FROM accounts")?;
+    let mut account_balances = stmt_accounts
+        .query([])?
+        .mapped(|row| {
+            row.get::<_, u32>(0)
+                .map(|a| (AccountId::from(a), AccountBalance::ZERO))
+        })
+        .collect::<Result<BTreeMap<AccountId, AccountBalance>, _>>()?;
+
     let mut stmt_select_notes = conn.prepare_cached(
         "SELECT n.account, n.value, n.is_change, scan_state.max_priority, t.block
          FROM sapling_received_notes n
@@ -641,7 +650,6 @@ pub(crate) fn get_wallet_summary(
          )",
     )?;
 
-    let mut account_balances: BTreeMap<AccountId, AccountBalance> = BTreeMap::new();
     let mut rows =
         stmt_select_notes.query(named_params![":summary_height": u32::from(summary_height)])?;
     while let Some(row) = rows.next()? {
@@ -689,9 +697,7 @@ pub(crate) fn get_wallet_summary(
             }
         };
 
-        account_balances
-            .entry(account)
-            .and_modify(|bal| {
+        account_balances.entry(account).and_modify(|bal| {
             bal.sapling_balance.spendable_value = (bal.sapling_balance.spendable_value
                 + spendable_value)
                 .expect("Spendable value cannot overflow");
@@ -701,14 +707,6 @@ pub(crate) fn get_wallet_summary(
             bal.sapling_balance.value_pending_spendability =
                 (bal.sapling_balance.value_pending_spendability + value_pending_spendability)
                     .expect("Value pending spendability cannot overflow");
-            })
-            .or_insert(AccountBalance {
-                sapling_balance: Balance {
-                    spendable_value,
-                    change_pending_confirmation,
-                    value_pending_spendability,
-                },
-                unshielded: NonNegativeAmount::ZERO,
         });
     }
 
@@ -734,15 +732,8 @@ pub(crate) fn get_wallet_summary(
                 SqliteClientError::CorruptedData(format!("Negative UTXO value {:?}", raw_value))
             })?;
 
-            account_balances
-                .entry(account)
-                .and_modify(|bal| {
-                    bal.unshielded =
-                        (bal.unshielded + value).expect("Unshielded value cannot overflow")
-                })
-                .or_insert(AccountBalance {
-                    sapling_balance: Balance::ZERO,
-                    unshielded: value,
+            account_balances.entry(account).and_modify(|bal| {
+                bal.unshielded = (bal.unshielded + value).expect("Unshielded value cannot overflow")
             });
         }
     }