zcash_client_backend: remove `WalletRead::is_valid_account_extfvk`

zcash_client_backend/CHANGELOG.md

@@ -64,6 +64,11 @@ and this library adheres to Rust's notion of
 - Almost all uses of `Amount` in `zcash_client_backend::zip321` have been replaced
   with `NonNegativeAmount`.
 
+### Removed
+- `zcash_client_backend::data_api::WalletRead::is_valid_account_extfvk` has been
+  removed; it was unused in the ECC mobile wallet SDKs and has been superseded by 
+  `get_account_for_ufvk`.
+
 ## [0.10.0] - 2023-09-25
 
 ### Notable Changes

zcash_client_backend/src/data_api.rs

@@ -23,7 +23,7 @@ use zcash_primitives::{
         },
         Transaction, TxId,
     },
-    zip32::{AccountId, ExtendedFullViewingKey},
+    zip32::AccountId,
 };
 
 use crate::{
@@ -326,13 +326,6 @@ pub trait WalletRead {
         ufvk: &UnifiedFullViewingKey,
     ) -> Result<Option<AccountId>, Self::Error>;
 
-    /// Checks whether the specified extended full viewing key is associated with the account.
-    fn is_valid_account_extfvk(
-        &self,
-        account: AccountId,
-        extfvk: &ExtendedFullViewingKey,
-    ) -> Result<bool, Self::Error>;
-
     /// Returns the wallet balances and sync status for an account given the specified minimum
     /// number of confirmations, or `Ok(None)` if the wallet has no balance data available.
     fn get_wallet_summary(
@@ -950,7 +943,7 @@ pub mod testing {
             components::{Amount, OutPoint},
             Transaction, TxId,
         },
-        zip32::{AccountId, ExtendedFullViewingKey},
+        zip32::AccountId,
     };
 
     use crate::{
@@ -1064,14 +1057,6 @@ pub mod testing {
             Ok(None)
         }
 
-        fn is_valid_account_extfvk(
-            &self,
-            _account: AccountId,
-            _extfvk: &ExtendedFullViewingKey,
-        ) -> Result<bool, Self::Error> {
-            Ok(false)
-        }
-
         fn get_wallet_summary(
             &self,
             _min_confirmations: u32,

zcash_client_sqlite/src/lib.rs

@@ -61,7 +61,7 @@ use zcash_primitives::{
         },
         Transaction, TxId,
     },
-    zip32::{AccountId, DiversifierIndex, ExtendedFullViewingKey},
+    zip32::{AccountId, DiversifierIndex},
 };
 
 use zcash_client_backend::{
@@ -247,14 +247,6 @@ impl<C: Borrow<rusqlite::Connection>, P: consensus::Parameters> WalletRead for W
         wallet::get_account_for_ufvk(self.conn.borrow(), &self.params, ufvk)
     }
 
-    fn is_valid_account_extfvk(
-        &self,
-        account: AccountId,
-        extfvk: &ExtendedFullViewingKey,
-    ) -> Result<bool, Self::Error> {
-        wallet::is_valid_account_extfvk(self.conn.borrow(), &self.params, account, extfvk)
-    }
-
     fn get_wallet_summary(
         &self,
         min_confirmations: u32,

zcash_client_sqlite/src/wallet.rs

@@ -65,7 +65,7 @@
 //! - `memo` the shielded memo associated with the output, if any.
 
 use incrementalmerkletree::Retention;
-use rusqlite::{self, named_params, OptionalExtension, ToSql};
+use rusqlite::{self, named_params, OptionalExtension};
 use shardtree::ShardTree;
 use std::cmp;
 use std::collections::{BTreeMap, HashMap};
@@ -89,10 +89,7 @@ use zcash_primitives::{
     memo::{Memo, MemoBytes},
     merkle_tree::read_commitment_tree,
     transaction::{components::Amount, Transaction, TxId},
-    zip32::{
-        sapling::{DiversifiableFullViewingKey, ExtendedFullViewingKey},
-        AccountId, DiversifierIndex,
-    },
+    zip32::{AccountId, DiversifierIndex},
 };
 
 use zcash_client_backend::{
@@ -461,37 +458,6 @@ pub(crate) fn get_account_for_ufvk<P: consensus::Parameters>(
     .map_err(SqliteClientError::from)
 }
 
-/// Checks whether the specified [`ExtendedFullViewingKey`] is valid and corresponds to the
-/// specified account.
-///
-/// [`ExtendedFullViewingKey`]: zcash_primitives::zip32::ExtendedFullViewingKey
-pub(crate) fn is_valid_account_extfvk<P: consensus::Parameters>(
-    conn: &rusqlite::Connection,
-    params: &P,
-    account: AccountId,
-    extfvk: &ExtendedFullViewingKey,
-) -> Result<bool, SqliteClientError> {
-    conn.prepare("SELECT ufvk FROM accounts WHERE account = ?")?
-        .query_row([u32::from(account).to_sql()?], |row| {
-            row.get(0).map(|ufvk_str: String| {
-                UnifiedFullViewingKey::decode(params, &ufvk_str)
-                    .map_err(SqliteClientError::CorruptedData)
-            })
-        })
-        .optional()
-        .map_err(SqliteClientError::from)
-        .and_then(|row| {
-            if let Some(ufvk) = row {
-                ufvk.map(|ufvk| {
-                    ufvk.sapling().map(|dfvk| dfvk.to_bytes())
-                        == Some(DiversifiableFullViewingKey::from(extfvk.clone()).to_bytes())
-                })
-            } else {
-                Ok(false)
-            }
-        })
-}
-
 pub(crate) trait ScanProgress {
     fn sapling_scan_progress(
         &self,