Fix long line formatting part 1

Author: scottming

apps/language_server/lib/language_server/experimental/code_mod/diff.ex

@@ -70,7 +70,21 @@ defmodule ElixirLS.LanguageServer.Experimental.CodeMod.Diff do
 
   defp apply_diff(:ins, {line, code_unit} = position, change, {current_line, prev_lines}) do
     current_line = [edit(change, line, code_unit, line, code_unit) | current_line]
-    advance(change, position, {current_line, prev_lines})
+    advance(:ins, change, position, {current_line, prev_lines})
+  end
+
+  defp advance(:ins, <<>>, position, edits) do
+    {position, edits}
+  end
+
+  for ending <- ["\r\n", "\r", "\n"] do
+    defp advance(:ins, <<unquote(ending), rest::binary>>, position, edits) do
+      advance(rest, position, edits)
+    end
+  end
+
+  defp advance(:ins, <<_c::utf8, rest::binary>>, position, edits) do
+    advance(rest, position, edits)
   end
 
   defp advance(<<>>, position, edits) do

apps/language_server/test/experimental/code_mod/format_test.exs

@@ -71,6 +71,76 @@ defmodule ElixirLS.Experimental.FormatTest do
       ]t == result
     end
 
+    test "it can handles long lines" do
+      unformatted = ~q[
+        defmodule Unformatted do
+          def foo1(s) do
+            s = very_loooooooooooooooooooooooooooooooooooooooooooooooooooooooooooonooooong(s) |> IO.inputs()
+            s
+          end
+
+          def very_loooooooooooooooooooooooooooooooooooooooooooooooooooooooooooonooooong(s) do
+            s
+          end
+        end
+      ]t
+
+      formatted = ~q[
+        defmodule Unformatted do
+          def foo1(s) do
+            s =
+              very_loooooooooooooooooooooooooooooooooooooooooooooooooooooooooooonooooong(s) |> IO.inputs()
+
+            s
+          end
+
+          def very_loooooooooooooooooooooooooooooooooooooooooooooooooooooooooooonooooong(s) do
+            s
+          end
+        end
+      ]t
+
+      assert {:ok, formatted} == modify(unformatted)
+    end
+
+    test "it can handles the case of long line split into multiple lines" do
+      unformatted = ~q[
+        defmodule Unformatted do
+          def foo(foo1, foo2, foo3, foo4, foo5, foo6, foo7, foo8, foo9, foo10, foo11, foo12, foo13, foo14, foo15, foo16) do
+            foo = foo14 <> foo15 <> foo16
+            {foo1, foo2, foo3, foo4, foo5, foo6, foo7, foo8, foo9, foo10, foo11, foo12, foo13, foo}
+          end
+        end
+      ]t
+      formatted = ~q[
+        defmodule Unformatted do
+          def foo(
+                foo1,
+                foo2,
+                foo3,
+                foo4,
+                foo5,
+                foo6,
+                foo7,
+                foo8,
+                foo9,
+                foo10,
+                foo11,
+                foo12,
+                foo13,
+                foo14,
+                foo15,
+                foo16
+              ) do
+            foo = foo14 <> foo15 <> foo16
+            {foo1, foo2, foo3, foo4, foo5, foo6, foo7, foo8, foo9, foo10, foo11, foo12, foo13, foo}
+          end
+        end
+      ]t
+
+      assert {:ok, formatted} == modify(unformatted)
+    end
+
     test "it handles extra lines" do
       assert {:ok, result} = ~q[
         defmodule  Unformatted do