Merge #806: Ensure there are no duplicated script_pubkeys in sqlite

b5fcddc Add sqlite migration to drop duplicated script_pubkeys rows (Steve Myers)
21c96c9 Add test for issue #801 (Alekos Filini)
c51d544 [wip] Ensure there are no duplicated script_pubkeys in sqlite (Alekos Filini)

Pull request description:

  ### Description

  Add a `UNIQUE` constraint on the script_pubkeys table so that it doesn't grow constantly when caching new addresses.

  Fixes #801

  ### Notes to the reviewers

  Adding it to the 0.25 milestone since it's just a bugfix.

  Still in draft because I need to add extra migration queries to clean up existing dbs.

  ### Checklists

  #### All Submissions:

  * [x] I've signed all my commits
  * [x] I followed the [contribution guidelines](https://github.com/bitcoindevkit/bdk/blob/master/CONTRIBUTING.md)
  * [x] I ran `cargo fmt` and `cargo clippy` before committing

  #### Bugfixes:

  * [ ] This pull request breaks the existing API
  * [x] I've added tests to reproduce the issue which are now passing
  * [x] I'm linking the issue being fixed by this PR

ACKs for top commit:
  notmandatory:
    ACK b5fcddc

Tree-SHA512: 7b10e453bb38af5c4f80f77692a56e37259680e50f9c2c9e554a0e5f04fb9cab897da6476c6c9930f1c501b455472984a1c92c4f137cff49acdc390d2e705107

src/database/sqlite.rs

@@ -57,7 +57,17 @@ static MIGRATIONS: &[&str] = &[
     "CREATE TABLE utxos (value INTEGER, keychain TEXT, vout INTEGER, txid BLOB, script BLOB, is_spent BOOLEAN DEFAULT 0);",
     "INSERT INTO utxos SELECT value, keychain, vout, txid, script, is_spent FROM utxos_old;",
     "DROP TABLE utxos_old;",
-    "CREATE UNIQUE INDEX idx_utxos_txid_vout ON utxos(txid, vout);"
+    "CREATE UNIQUE INDEX idx_utxos_txid_vout ON utxos(txid, vout);",
+    // Fix issue https://github.com/bitcoindevkit/bdk/issues/801: drop duplicated script_pubkeys
+    "ALTER TABLE script_pubkeys RENAME TO script_pubkeys_old;",
+    "DROP INDEX idx_keychain_child;",
+    "DROP INDEX idx_script;",
+    "CREATE TABLE script_pubkeys (keychain TEXT, child INTEGER, script BLOB);",
+    "CREATE INDEX idx_keychain_child ON script_pubkeys(keychain, child);",
+    "CREATE INDEX idx_script ON script_pubkeys(script);",
+    "CREATE UNIQUE INDEX idx_script_pks_unique ON script_pubkeys(keychain, child);",
+    "INSERT OR REPLACE INTO script_pubkeys SELECT keychain, child, script FROM script_pubkeys_old;",
+    "DROP TABLE script_pubkeys_old;"
 ];
 
 /// Sqlite database stored on filesystem
@@ -88,7 +98,7 @@ impl SqliteDatabase {
         child: u32,
         script: &[u8],
     ) -> Result<i64, Error> {
-        let mut statement = self.connection.prepare_cached("INSERT INTO script_pubkeys (keychain, child, script) VALUES (:keychain, :child, :script)")?;
+        let mut statement = self.connection.prepare_cached("INSERT OR REPLACE INTO script_pubkeys (keychain, child, script) VALUES (:keychain, :child, :script)")?;
         statement.execute(named_params! {
             ":keychain": keychain,
             ":child": child,
@@ -1096,4 +1106,44 @@ pub mod test {
     fn test_check_descriptor_checksum() {
         crate::database::test::test_check_descriptor_checksum(get_database());
     }
+
+    // Issue 801: https://github.com/bitcoindevkit/bdk/issues/801
+    #[test]
+    fn test_unique_spks() {
+        use crate::bitcoin::hashes::hex::FromHex;
+        use crate::database::*;
+
+        let mut db = get_database();
+
+        let script = Script::from(
+            Vec::<u8>::from_hex("76a91402306a7c23f3e8010de41e9e591348bb83f11daa88ac").unwrap(),
+        );
+        let path = 42;
+        let keychain = KeychainKind::External;
+
+        for _ in 0..100 {
+            db.set_script_pubkey(&script, keychain, path).unwrap();
+        }
+
+        let mut statement = db
+            .connection
+            .prepare_cached(
+                "select keychain,child,count(child) from script_pubkeys group by keychain,child;",
+            )
+            .unwrap();
+        let mut rows = statement.query([]).unwrap();
+        while let Some(row) = rows.next().unwrap() {
+            let keychain: String = row.get(0).unwrap();
+            let child: u32 = row.get(1).unwrap();
+            let count: usize = row.get(2).unwrap();
+
+            assert!(
+                count == 1,
+                "keychain={}, child={}, count={}",
+                keychain,
+                child,
+                count
+            );
+        }
+    }
 }