Support older sqlite versions.

The `FALSE` constant was introduced in sqlite version 3.23.0,
but Android does not support this version of sqlite until API
level 30; we support back to Android API 27 so we have to use
`0` as the constant for `FALSE` instead.

zcash_client_sqlite/CHANGELOG.md

@@ -7,6 +7,11 @@ and this library adheres to Rust's notion of
 
 ## [Unreleased]
 
+### Changed
+- The `v_tx_outputs` view was modified slightly to support older versions of
+  `sqlite`.
+
+
 ## [0.11.1] - 2024-08-21
 
 ### Fixed

zcash_client_sqlite/src/wallet/db.rs

@@ -883,7 +883,7 @@ SELECT transactions.txid            AS txid,
        NULL                         AS to_account_id,
        sent_notes.to_address        AS to_address,
        sent_notes.value             AS value,
-       FALSE                        AS is_change,
+       0                            AS is_change,
        sent_notes.memo              AS memo
 FROM sent_notes
 JOIN transactions

zcash_client_sqlite/src/wallet/init/migrations.rs

@@ -15,6 +15,7 @@ mod sapling_memo_consistency;
 mod sent_notes_to_internal;
 mod shardtree_support;
 mod spend_key_available;
+mod support_legacy_sqlite;
 mod tx_retrieval_queue;
 mod ufvk_support;
 mod utxos_table;
@@ -74,6 +75,8 @@ pub(super) fn all_migrations<P: consensus::Parameters + 'static>(
     //            \                          \     ephemeral_addresses     /                       /
     //             \                          \            |              /                       /
     //              ------------------------------ tx_retrieval_queue ----------------------------
+    //                                                     |
+    //                                            support_legacy_sqlite
     vec![
         Box::new(initial_setup::Migration {}),
         Box::new(utxos_table::Migration {}),
@@ -131,6 +134,7 @@ pub(super) fn all_migrations<P: consensus::Parameters + 'static>(
         Box::new(tx_retrieval_queue::Migration {
             params: params.clone(),
         }),
+        Box::new(support_legacy_sqlite::Migration),
     ]
 }
 

zcash_client_sqlite/src/wallet/init/migrations/support_legacy_sqlite.rs

@@ -0,0 +1,91 @@
+//! A migration that removes the use of `FALSE` in sqlite view definitions.
+//! This is necessary to support older
+use std::collections::HashSet;
+
+use rusqlite;
+use schemer;
+use schemer_rusqlite::RusqliteMigration;
+use uuid::Uuid;
+
+use crate::wallet::init::{migrations::tx_retrieval_queue, WalletMigrationError};
+
+pub(super) const MIGRATION_ID: Uuid = Uuid::from_u128(0xc9ed1fb5_b2c3_467f_89dc_2591dcca5562);
+
+const DEPENDENCIES: &[Uuid] = &[tx_retrieval_queue::MIGRATION_ID];
+
+pub(super) struct Migration;
+
+impl schemer::Migration for Migration {
+    fn id(&self) -> Uuid {
+        MIGRATION_ID
+    }
+
+    fn dependencies(&self) -> HashSet<Uuid> {
+        DEPENDENCIES.iter().copied().collect()
+    }
+
+    fn description(&self) -> &'static str {
+        "Removes the FALSE keyword from the v_tx_outputs view definition"
+    }
+}
+
+impl RusqliteMigration for Migration {
+    type Error = WalletMigrationError;
+
+    fn up(&self, transaction: &rusqlite::Transaction) -> Result<(), WalletMigrationError> {
+        transaction.execute_batch(
+            r#"
+            DROP VIEW v_tx_outputs;
+            CREATE VIEW v_tx_outputs AS
+            -- select all outputs received by the wallet
+            SELECT transactions.txid            AS txid,
+                   ro.pool                      AS output_pool,
+                   ro.output_index              AS output_index,
+                   sent_notes.from_account_id   AS from_account_id,
+                   ro.account_id                AS to_account_id,
+                   NULL                         AS to_address,
+                   ro.value                     AS value,
+                   ro.is_change                 AS is_change,
+                   ro.memo                      AS memo
+            FROM v_received_outputs ro
+            JOIN transactions
+                ON transactions.id_tx = ro.transaction_id
+            -- join to the sent_notes table to obtain `from_account_id`
+            LEFT JOIN sent_notes ON sent_notes.id = ro.sent_note_id
+            UNION
+            -- select all outputs sent from the wallet to external recipients
+            SELECT transactions.txid            AS txid,
+                   sent_notes.output_pool       AS output_pool,
+                   sent_notes.output_index      AS output_index,
+                   sent_notes.from_account_id   AS from_account_id,
+                   NULL                         AS to_account_id,
+                   sent_notes.to_address        AS to_address,
+                   sent_notes.value             AS value,
+                   0                            AS is_change,
+                   sent_notes.memo              AS memo
+            FROM sent_notes
+            JOIN transactions
+                ON transactions.id_tx = sent_notes.tx
+            LEFT JOIN v_received_outputs ro ON ro.sent_note_id = sent_notes.id
+            -- exclude any sent notes for which a row exists in the v_received_outputs view
+            WHERE ro.account_id IS NULL
+        "#,
+        )?;
+
+        Ok(())
+    }
+
+    fn down(&self, _: &rusqlite::Transaction) -> Result<(), WalletMigrationError> {
+        Err(WalletMigrationError::CannotRevert(MIGRATION_ID))
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::wallet::init::migrations::tests::test_migrate;
+
+    #[test]
+    fn migrate() {
+        test_migrate(&[super::MIGRATION_ID]);
+    }
+}