From fd899803bf1297cf575b93bd59d1b189694114af Mon Sep 17 00:00:00 2001
From: Steve Cohen <scohen@scohen.org>
Date: Thu, 1 Dec 2022 22:04:52 -0800
Subject: [PATCH] The code action needs to fix up the line numbers

Code mods deal with snippets of code that need to have their line
numbers fixed up by the code actions.
---
 .../code_action/replace_with_underscore.ex         | 11 +++++++++++
 .../code_action/replace_with_underscore_test.exs   | 14 ++++++++++++++
 2 files changed, 25 insertions(+)

diff --git a/apps/language_server/lib/language_server/experimental/provider/code_action/replace_with_underscore.ex b/apps/language_server/lib/language_server/experimental/provider/code_action/replace_with_underscore.ex
index 5ce3a8e89..688619f53 100644
--- a/apps/language_server/lib/language_server/experimental/provider/code_action/replace_with_underscore.ex
+++ b/apps/language_server/lib/language_server/experimental/provider/code_action/replace_with_underscore.ex
@@ -2,11 +2,13 @@ defmodule ElixirLS.LanguageServer.Experimental.Provider.CodeAction.ReplaceWithUn
   @moduledoc """
   A code action that prefixes unused variables with an underscore
   """
+
   alias ElixirLS.LanguageServer.Experimental.CodeMod
   alias ElixirLS.LanguageServer.Experimental.CodeMod.Ast
   alias ElixirLS.LanguageServer.Experimental.Protocol.Requests.CodeAction
   alias ElixirLS.LanguageServer.Experimental.Protocol.Types.CodeAction, as: CodeActionResult
   alias ElixirLS.LanguageServer.Experimental.Protocol.Types.Diagnostic
+  alias ElixirLS.LanguageServer.Experimental.Protocol.Types.TextEdit
   alias ElixirLS.LanguageServer.Experimental.Protocol.Types.WorkspaceEdit
   alias ElixirLS.LanguageServer.Experimental.SourceFile
 
@@ -37,6 +39,8 @@ defmodule ElixirLS.LanguageServer.Experimental.Provider.CodeAction.ReplaceWithUn
           :error
 
         [_ | _] ->
+          text_edits = Enum.map(text_edits, &update_line(&1, one_based_line))
+
           reply =
             CodeActionResult.new(
               title: "Rename to _#{variable_name}",
@@ -49,6 +53,13 @@ defmodule ElixirLS.LanguageServer.Experimental.Provider.CodeAction.ReplaceWithUn
     end
   end
 
+  defp update_line(%TextEdit{} = text_edit, line_number) do
+    text_edit =
+      text_edit
+      |> put_in([:range, :start, :line], line_number - 1)
+      |> put_in([:range, :end, :line], line_number - 1)
+  end
+
   defp extract_variable_and_line(%Diagnostic{} = diagnostic) do
     with {:ok, variable_name} <- extract_variable_name(diagnostic.message),
          {:ok, line} <- extract_line(diagnostic) do
diff --git a/apps/language_server/test/experimental/provider/code_action/replace_with_underscore_test.exs b/apps/language_server/test/experimental/provider/code_action/replace_with_underscore_test.exs
index 71feb57bb..baa1195f0 100644
--- a/apps/language_server/test/experimental/provider/code_action/replace_with_underscore_test.exs
+++ b/apps/language_server/test/experimental/provider/code_action/replace_with_underscore_test.exs
@@ -131,4 +131,18 @@ defmodule ElixirLS.LanguageServer.Experimental.Provider.CodeAction.ReplaceWithUn
     assert [%CodeActionReply{edit: %{changes: %{^file_uri => [edit]}}}] = apply(code_action)
     assert edit.new_text == "_"
   end
+
+  test "works with multiple lines" do
+    {file_uri, code_action} = ~S[
+      defmodule MyModule do
+        def my_func(a) do
+        end
+      end
+    ] |> code_action("/project/file.ex", 1, "a")
+
+    assert [%CodeActionReply{edit: %{changes: %{^file_uri => [edit]}}}] = apply(code_action)
+    assert edit.new_text == "_"
+    assert edit.range.start.line == 1
+    assert edit.range.end.line == 1
+  end
 end