fix: address review — disambiguate nil driver from empty DB, explicit @mainactor

Author: datlechin

TablePro/Core/Autocomplete/SQLSchemaProvider.swift

@@ -109,8 +109,8 @@ actor SQLSchemaProvider {
         tables = newTables
     }
 
-    func fetchFreshTables() async throws -> [TableInfo] {
-        guard let driver = cachedDriver else { return [] }
+    func fetchFreshTables() async throws -> [TableInfo]? {
+        guard let driver = cachedDriver else { return nil }
         let fresh = try await driver.fetchTables()
         tables = fresh
         return fresh

TablePro/ViewModels/SidebarViewModel.swift

@@ -29,8 +29,7 @@ struct LiveTableFetcher: TableFetcher {
     func fetchTables(force: Bool) async throws -> [TableInfo] {
         if let provider = schemaProvider {
             if force {
-                let fresh = try await provider.fetchFreshTables()
-                if !fresh.isEmpty { return fresh }
+                if let fresh = try await provider.fetchFreshTables() { return fresh }
             } else {
                 let cached = await provider.getTables()
                 if !cached.isEmpty { return cached }

TablePro/Views/Main/MainContentCoordinator.swift

@@ -313,7 +313,7 @@ final class MainContentCoordinator {
     }
 
     func reloadSidebar() {
-        Task {
+        Task { @MainActor in
             await schemaProvider.invalidateTables()
             sidebarViewModel?.forceLoadTables()
         }

TableProTests/ViewModels/LiveTableFetcherTests.swift

@@ -179,7 +179,6 @@ struct LiveTableFetcherTests {
         let provider = SQLSchemaProvider()
         await provider.loadSchema(using: mockDriver)
 
-        await provider.invalidateTables()
         let freshTables = [
             TestFixtures.makeTableInfo(name: "alpha"),
             TestFixtures.makeTableInfo(name: "beta")