Normalize newlines in initial smart cell editor content (#1400)

lib/livebook/session.ex

@@ -1072,6 +1072,15 @@ defmodule Livebook.Session do
   end
 
   def handle_info({:runtime_smart_cell_started, id, info}, state) do
+    info =
+      if info.editor do
+        normalize_newlines = &String.replace(&1, "\r\n", "\n")
+        info = update_in(info.source, normalize_newlines)
+        update_in(info.editor.source, normalize_newlines)
+      else
+        info
+      end
+
     case Notebook.fetch_cell_and_section(state.data.notebook, id) do
       {:ok, cell, _section} ->
         delta = Livebook.JSInterop.diff(cell.source, info.source)

test/livebook/live_markdown/import_test.exs

@@ -736,7 +736,7 @@ defmodule Livebook.LiveMarkdown.ImportTest do
     end
 
     test "imports snippets with output info string" do
-      # We now explicitly mark every output sinppet with <!-- livebook:{"output":true} -->
+      # We now explicitly mark every output snippet with <!-- livebook:{"output":true} -->
       # and use empty snippets for textual outputs, however previously
       # we supported ```output too, so let's ensure they still work
 

test/livebook/session_test.exs

@@ -694,6 +694,48 @@ defmodule Livebook.SessionTest do
       assert_receive {:editor_source, "content!"}
     end
 
+    test "normalizes line endings in smart cells having an editor" do
+      # Prior to Livebook 0.7.0 the editor would use system line endings,
+      # hence smart cells having editor may have CRLF in their persisted
+      # source, so we want to normalize it upfront
+
+      smart_cell = %{Notebook.Cell.new(:smart) | kind: "text", source: ""}
+      notebook = %{Notebook.new() | sections: [%{Notebook.Section.new() | cells: [smart_cell]}]}
+      session = start_session(notebook: notebook)
+
+      runtime = connected_noop_runtime()
+      Session.set_runtime(session.pid, runtime)
+
+      send(
+        session.pid,
+        {:runtime_smart_cell_definitions, [%{kind: "text", name: "Text", requirement: nil}]}
+      )
+
+      server_pid = self()
+
+      send(
+        session.pid,
+        {:runtime_smart_cell_started, smart_cell.id,
+         %{
+           source: "content\r\nmultiline",
+           js_view: %{ref: smart_cell.id, pid: server_pid, assets: %{}},
+           editor: %{language: nil, placement: :bottom, source: "content\r\nmultiline"}
+         }}
+      )
+
+      assert %{
+               notebook: %{
+                 sections: [
+                   %{
+                     cells: [
+                       %{source: "content\nmultiline", editor: %{source: "content\nmultiline"}}
+                     ]
+                   }
+                 ]
+               }
+             } = Session.get_data(session.pid)
+    end
+
     test "pings the smart cell before evaluation to await all incoming messages" do
       smart_cell = %{Notebook.Cell.new(:smart) | kind: "text", source: "1"}
       notebook = %{Notebook.new() | sections: [%{Notebook.Section.new() | cells: [smart_cell]}]}