Fix dialyzer warnings

lib/livebook/config.ex

@@ -310,6 +310,7 @@ defmodule Livebook.Config do
   @doc """
   Aborts booting due to a configuration error.
   """
+  @spec abort!(String.t()) :: no_return()
   def abort!(message) do
     IO.puts("\nERROR!!! [Livebook] " <> message)
     System.halt(1)

lib/livebook/evaluator/io_proxy.ex

@@ -357,7 +357,6 @@ defmodule Livebook.Evaluator.IOProxy do
     end
   end
 
-  defp binary_to_list(data, _) when is_list(data), do: data
   defp binary_to_list(data, :unicode) when is_binary(data), do: String.to_charlist(data)
   defp binary_to_list(data, :latin1) when is_binary(data), do: :erlang.binary_to_list(data)
 

lib/livebook/file_system/file.ex

@@ -160,7 +160,7 @@ defmodule Livebook.FileSystem.File do
   @doc """
   Creates the given directory unless it already exists.
   """
-  @spec create_dir(t()) :: {:ok, FileSystem.access()} | {:error, FileSystem.error()}
+  @spec create_dir(t()) :: :ok | {:error, FileSystem.error()}
   def create_dir(file) do
     FileSystem.create_dir(file.file_system, file.path)
   end

lib/livebook/file_system/local.ex

@@ -110,7 +110,7 @@ defimpl Livebook.FileSystem, for: Livebook.FileSystem.Local do
   def remove(_file_system, path) do
     case File.rm_rf(path) do
       {:ok, _paths} -> :ok
-      {:error, error} -> FileSystem.Utils.posix_error(error)
+      {:error, error, _paths} -> FileSystem.Utils.posix_error(error)
     end
   end
 

lib/livebook/runtime/erl_dist/logger_gl_backend.ex

@@ -105,16 +105,6 @@ defmodule Livebook.Runtime.ErlDist.LoggerGLBackend do
     info[:dictionary][:"$initial_call"] == {Livebook.Evaluator.IOProxy, :init, 1}
   end
 
-  defp async_io(name, output) when is_atom(name) do
-    case Process.whereis(name) do
-      device when is_pid(device) ->
-        async_io(device, output)
-
-      nil ->
-        raise "no device registered with the name #{inspect(name)}"
-    end
-  end
-
   defp async_io(device, output) when is_pid(device) do
     send(device, {:io_request, self(), make_ref(), {:put_chars, :unicode, output}})
   end

lib/livebook/session/data.ex

@@ -1106,7 +1106,8 @@ defmodule Livebook.Session.Data do
 
     # Note: the session LV drops cell's source once it's no longer needed
     new_source =
-      cell.source && JSInterop.apply_delta_to_string(transformed_new_delta, cell.source)
+      Map.get(cell, :source) &&
+        JSInterop.apply_delta_to_string(transformed_new_delta, cell.source)
 
     data_actions
     |> set!(notebook: Notebook.update_cell(data.notebook, cell.id, &%{&1 | source: new_source}))

lib/livebook/users/user.ex

@@ -41,7 +41,8 @@ defmodule Livebook.Users.User do
   is returned, where `user` is partially updated by using
   only the valid attributes.
   """
-  @spec change(t(), %{binary() => any()}) :: {:ok, t()} | {:error, list(String.t()), t()}
+  @spec change(t(), %{binary() => any()}) ::
+          {:ok, t()} | {:error, list({atom(), String.t()}), t()}
   def change(user, attrs \\ %{}) do
     {user, []}
     |> change_name(attrs)

test/support/noop_runtime.ex

@@ -9,7 +9,7 @@ defmodule Livebook.Runtime.NoopRuntime do
   def new(), do: %__MODULE__{}
 
   defimpl Livebook.Runtime do
-    def connect(_), do: :ok
+    def connect(_), do: make_ref()
     def disconnect(_), do: :ok
     def evaluate_code(_, _, _, _, _ \\ []), do: :ok
     def forget_evaluation(_, _), do: :ok