fix: oban lifeline plugin errors

lib/ecto_libsql/native.ex

@@ -704,13 +704,17 @@ defmodule EctoLibSql.Native do
             num_rows
           end
 
-        # For INSERT/UPDATE/DELETE without RETURNING, columns and rows will be empty
-        # Set them to nil to match Ecto's expectations
-        {columns, rows} =
-          if command in [:insert, :update, :delete] and columns == [] and rows == [] do
-            {nil, nil}
-          else
-            {columns, rows}
+        # Normalize: columns MUST be a list, rows nil only for successful writes without RETURNING
+        columns = columns || []
+
+        rows =
+          cond do
+            command in [:insert, :update, :delete] and columns == [] and rows == [] and actual_num_rows > 0 ->
+              nil
+            rows == nil ->
+              []
+            true ->
+              rows
           end
 
         result = %EctoLibSql.Result{
@@ -767,13 +771,17 @@ defmodule EctoLibSql.Native do
           "rows" => rows,
           "num_rows" => num_rows
         } ->
-          # For INSERT/UPDATE/DELETE without actual returned rows, normalise empty lists to nil
-          # This ensures consistency with non-transactional path
-          {columns, rows} =
-            if command in [:insert, :update, :delete] and columns == [] and rows == [] do
-              {nil, nil}
-            else
-              {columns, rows}
+          # Normalize: columns MUST be a list, rows nil only for successful writes without RETURNING
+          columns = columns || []
+
+          rows =
+            cond do
+              command in [:insert, :update, :delete] and columns == [] and rows == [] and num_rows > 0 ->
+                nil
+              rows == nil ->
+                []
+              true ->
+                rows
             end
 
           result = %EctoLibSql.Result{
@@ -790,10 +798,13 @@ defmodule EctoLibSql.Native do
       end
     else
       # Use execute_with_transaction for INSERT/UPDATE/DELETE without RETURNING
+      # columns MUST be [] (not nil), rows should be nil
       case execute_with_transaction(trx_id, conn_id, statement, args_for_execution) do
         num_rows when is_integer(num_rows) ->
           result = %EctoLibSql.Result{
             command: command,
+            columns: [],
+            rows: nil,
             num_rows: num_rows
           }
 

lib/ecto_libsql/query.ex

@@ -38,7 +38,49 @@ defmodule EctoLibSql.Query do
 
     def describe(query, _opts), do: query
 
-    def encode(_query, params, _opts), do: params
+    # Convert Elixir types to SQLite-compatible values before sending to NIF
+    def encode(_query, params, _opts) do
+      Enum.map(params, &encode_param/1)
+    end
+
+    defp encode_param(%DateTime{} = dt), do: DateTime.to_iso8601(dt)
+    defp encode_param(%NaiveDateTime{} = dt), do: NaiveDateTime.to_iso8601(dt)
+    defp encode_param(%Date{} = d), do: Date.to_iso8601(d)
+    defp encode_param(%Time{} = t), do: Time.to_iso8601(t)
+    defp encode_param(%Decimal{} = d), do: Decimal.to_string(d)
+    defp encode_param(value), do: value
+
+    # Normalize results for ecto_sql compatibility.
+    # Rules:
+    # 1. columns MUST ALWAYS be a list (even empty []), NEVER nil
+    # 2. rows should be nil only for write commands without RETURNING that affected rows
+    # 3. For all other cases (SELECT, RETURNING queries), rows must be a list
+    def decode(_query, result, _opts) when is_map(result) do
+      columns = case Map.get(result, :columns) do
+        nil -> []
+        cols when is_list(cols) -> cols
+        _ -> []
+      end
+
+      cmd = Map.get(result, :command)
+      rows = Map.get(result, :rows)
+      num_rows = Map.get(result, :num_rows, 0)
+
+      rows = cond do
+        # Write commands that affected rows but have no RETURNING -> rows should be nil
+        cmd in [:insert, :update, :delete] and rows == [] and num_rows > 0 and columns == [] ->
+          nil
+        # All other cases: rows must be a list
+        rows == nil ->
+          []
+        true ->
+          rows
+      end
+
+      result
+      |> Map.put(:columns, columns)
+      |> Map.put(:rows, rows)
+    end
 
     def decode(_query, result, _opts), do: result
   end