zcash_client_sqlite: Fix `WalletRead::get_address` return value

Previously it would return an error if the account identifier did not
correspond to a known account.

zcash_client_backend/src/data_api.rs

@@ -116,7 +116,6 @@ pub trait WalletRead {
     ///
     /// This will return `Ok(None)` if the account identifier does not correspond
     /// to a known account.
-    // TODO: This does not appear to be the case.
     fn get_address(&self, account: AccountId) -> Result<Option<UnifiedAddress>, Self::Error>;
 
     /// Returns all unified full viewing keys known to this wallet.

zcash_client_sqlite/CHANGELOG.md

@@ -66,6 +66,11 @@ and this library adheres to Rust's notion of
     `zcash_client_backend::data_api::WalletRead::get_unified_full_viewing_keys`
     instead).
 
+### Fixed
+- The `zcash_client_backend::data_api::WalletRead::get_address` implementation
+  for `zcash_client_sqlite::WalletDb` now correctly returns `Ok(None)` if the
+  account identifier does not correspond to a known account.
+
 ### Deprecated
 - A number of public API methods that are used internally to support the
   `zcash_client_backend::data_api::{WalletRead, WalletWrite}` interfaces have

zcash_client_sqlite/src/wallet.rs

@@ -178,11 +178,14 @@ pub(crate) fn get_address_ua<P: consensus::Parameters>(
     account: AccountId,
 ) -> Result<Option<UnifiedAddress>, SqliteClientError> {
     // This returns the first diversified address, which will be the default one.
-    let addr: Option<String> = wdb.conn.query_row_named(
-        "SELECT address FROM accounts WHERE account = :account",
-        &[(":account", &u32::from(account))],
-        |row| row.get(0),
-    )?;
+    let addr: Option<String> = wdb
+        .conn
+        .query_row_named(
+            "SELECT address FROM accounts WHERE account = :account",
+            &[(":account", &u32::from(account))],
+            |row| row.get(0),
+        )
+        .optional()?;
 
     addr.map(|addr_str| {
         RecipientAddress::decode(&wdb.params, &addr_str)