[Fix] IOS Migrations (#164)

Author: stevensJourney

CHANGELOG.md

@@ -3,6 +3,10 @@
 ## 1.0.0-BETA29 (unreleased)
 
 * Fix potential race condition between jobs in `connect()` and `disconnect()`.
+* [iOS] Fixed issue where automatic driver migrations would fail with the error:
+```
+Sqlite operation failure database is locked attempted to run migration and failed. closing connection
+```
 
 ## 1.0.0-BETA28
 

core/src/iosMain/kotlin/com/powersync/DatabaseDriverFactory.ios.kt

@@ -1,8 +1,10 @@
 package com.powersync
 
+import app.cash.sqldelight.db.QueryResult
 import co.touchlab.sqliter.DatabaseConfiguration
 import co.touchlab.sqliter.DatabaseConfiguration.Logging
 import co.touchlab.sqliter.DatabaseConnection
+import co.touchlab.sqliter.NO_VERSION_CHECK
 import co.touchlab.sqliter.interop.Logger
 import co.touchlab.sqliter.interop.SqliteErrorType
 import co.touchlab.sqliter.sqlite3.sqlite3_commit_hook
@@ -68,7 +70,13 @@ public actual class DatabaseDriverFactory {
                         configuration =
                             DatabaseConfiguration(
                                 name = dbFilename,
-                                version = schema.version.toInt(),
+                                version =
+                                    if (!readOnly) {
+                                        schema.version.toInt()
+                                    } else {
+                                        // Don't do migrations on read only connections
+                                        NO_VERSION_CHECK
+                                    },
                                 create = { connection ->
                                     wrapConnection(connection) {
                                         schema.create(
@@ -106,6 +114,15 @@ public actual class DatabaseDriverFactory {
             driver.execute("PRAGMA query_only=true")
         }
 
+        // Ensure internal read pool has created a connection at this point. This makes connection
+        // initialization a bit more deterministic.
+        driver.executeQuery(
+            identifier = null,
+            sql = "SELECT 1",
+            mapper = { QueryResult.Value(it.getLong(0)) },
+            parameters = 0,
+        )
+
         deferredDriver.setDriver(driver)
 
         return driver