Do not create the wallet struct directly; instead, call new.

The bug comes with the SQLx-sqlite pool bug, where several connections are
created by default, but the `new` function takes care of that, fixing that bug
by making a single instance of the database.

If constructed directly, the pool would create several connections to the
database, which in most instances is fine, but with SQLite :memory: each
connection is entirely independent.

Author: crodas

crates/cdk-sqlite/src/common.rs

@@ -31,5 +31,13 @@ pub async fn create_sqlite_pool(
         .connect_with(db_options)
         .await?;
 
+    if path.contains(":memory:") {
+        // Ensure that the pool has the minimum number of connections open
+        // This makes sure the pool initializes with exactly one connection.
+        // This is necessary because `min_connections` does not guarantee
+        // an immediate connection unless it is actively used or explicitly initialized.
+        pool.acquire().await?;
+    }
+
     Ok(pool)
 }

crates/cdk-sqlite/src/wallet/memory.rs

@@ -6,11 +6,10 @@ use super::WalletSqliteDatabase;
 
 /// Creates a new in-memory [`WalletSqliteDatabase`] instance
 pub async fn empty() -> Result<WalletSqliteDatabase, Error> {
-    let db = WalletSqliteDatabase {
-        pool: sqlx::sqlite::SqlitePool::connect(":memory:")
-            .await
-            .map_err(|e| Error::Database(Box::new(e)))?,
-    };
+    #[cfg(not(feature = "sqlcipher"))]
+    let db = WalletSqliteDatabase::new(":memory:").await?;
+    #[cfg(feature = "sqlcipher")]
+    let db = WalletSqliteDatabase::new(":memory:", "memory".to_owned()).await?;
     db.migrate().await;
     Ok(db)
 }