From 89454809c6e9b8586bdb5fc2289b7788541915ae Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ton=C4=87i=20Gali=C4=87?= <tuxified@gmail.com>
Date: Fri, 11 Feb 2022 11:36:24 +0100
Subject: [PATCH 1/4] POC for "rename" functionality

LSPs can offer a rename capability to rename a "symbol" across a workspace.
We're not there yet, but this is a starting point. In VS Code it can be used by
right clicking a symbol (currently variable or call to local function) and
selecting "Rename symbol". A dialog should pop up asking for a new name.

Official spec:
https://microsoft.github.io/language-server-protocol/specifications/specification-current/#textDocument_rename
---
 .../lib/language_server/protocol.ex           |  19 ++
 .../lib/language_server/providers/rename.ex   | 100 ++++++++
 .../lib/language_server/server.ex             |  22 ++
 .../test/providers/rename_test.exs            | 213 ++++++++++++++++++
 .../test/support/fixtures/rename_example.exs  |  67 ++++++
 5 files changed, 421 insertions(+)
 create mode 100644 apps/language_server/lib/language_server/providers/rename.ex
 create mode 100644 apps/language_server/test/providers/rename_test.exs
 create mode 100644 apps/language_server/test/support/fixtures/rename_example.exs

diff --git a/apps/language_server/lib/language_server/protocol.ex b/apps/language_server/lib/language_server/protocol.ex
index faf5af976..044f496d0 100644
--- a/apps/language_server/lib/language_server/protocol.ex
+++ b/apps/language_server/lib/language_server/protocol.ex
@@ -181,6 +181,25 @@ defmodule ElixirLS.LanguageServer.Protocol do
     end
   end
 
+  defmacro rename_req(id, uri, line, character, new_name) do
+    quote do
+      request(unquote(id), "textDocument/rename", %{
+        "textDocument" => %{"uri" => unquote(uri)},
+        "position" => %{"line" => unquote(line), "character" => unquote(character)},
+        "newName" => unquote(new_name)
+      })
+    end
+  end
+
+  defmacro prepare_rename_req(id, uri, line, character) do
+    quote do
+      request(unquote(id), "textDocument/prepareRename", %{
+        "textDocument" => %{"uri" => unquote(uri)},
+        "position" => %{"line" => unquote(line), "character" => unquote(character)}
+      })
+    end
+  end
+
   defmacro execute_command_req(id, command, arguments) do
     quote do
       request(unquote(id), "workspace/executeCommand", %{
diff --git a/apps/language_server/lib/language_server/providers/rename.ex b/apps/language_server/lib/language_server/providers/rename.ex
new file mode 100644
index 000000000..2c31af2bb
--- /dev/null
+++ b/apps/language_server/lib/language_server/providers/rename.ex
@@ -0,0 +1,100 @@
+defmodule ElixirLS.LanguageServer.Providers.Rename do
+  @moduledoc """
+  Provides functionality to rename a symbol inside a workspace
+
+  https://microsoft.github.io/language-server-protocol/specifications/specification-current/#textDocument_rename
+  """
+
+  alias ElixirLS.LanguageServer.SourceFile
+  #import ElixirLS.LanguageServer.Protocol
+
+  def rename(%SourceFile{} = source_file, start_uri, line, character, new_name) do
+    edits =
+      with %{context: {context, char_ident}} when context in [:local_or_var, :local_call] <-
+             Code.Fragment.surround_context(source_file.text, {line, character}),
+           %ElixirSense.Location{} = definition <-
+             ElixirSense.definition(source_file.text, line, character),
+           references <- ElixirSense.references(source_file.text, line, character) do
+ 
+
+        length_old = length(char_ident)
+
+        [
+          %{
+            uri: start_uri,
+            range:
+              adjust_range(
+                definition.line,
+                definition.column,
+                definition.line,
+                definition.column + length_old
+              )
+          }
+          | repack_references(references, start_uri)
+        ]
+      else
+        _ ->
+          []
+      end
+
+    changes =
+      edits
+      |> Enum.group_by(& &1.uri)
+      |> Enum.map(fn {uri, edits} ->
+        %{
+          "textDocument" => %{
+            "uri" => uri,
+            "version" => source_file.version + 1
+          },
+          "edits" =>
+            Enum.map(edits, fn edit ->
+              %{"range" => edit.range, "newText" => new_name}
+            end)
+        }
+      end)
+
+    {:ok, %{"documentChanges" => changes}}
+  end
+
+  def prepare(%SourceFile{} = source_file, _uri, line, character) do
+    result =
+      with %{
+             begin: {start_line, start_col},
+             end: {end_line, end_col},
+             context: {context, char_ident}
+           } when context in [:local_or_var, :local_call] <- Code.Fragment.surround_context(source_file.text, {line, character}) do
+        %{
+          range: adjust_range(start_line, start_col, end_line, end_col),
+          placeholder: to_string(char_ident)
+        }
+      else
+        _ ->
+          # Not a variable or local call, skipping for now
+          nil
+      end
+
+    {:ok, result}
+  end
+
+  defp repack_references(references, uri) do
+    for reference <- references do
+      %{
+        uri: uri,
+        range: %{
+          end: %{character: reference.range.end.column - 1, line: reference.range.end.line - 1},
+          start: %{
+            character: reference.range.start.column - 1,
+            line: reference.range.start.line - 1
+          }
+        }
+      }
+    end
+  end
+
+  defp adjust_range(start_line, start_character, end_line, end_character) do
+    %{
+      start: %{line: start_line - 1, character: start_character - 1},
+      end: %{line: end_line - 1, character: end_character - 1}
+    }
+  end
+end
diff --git a/apps/language_server/lib/language_server/server.ex b/apps/language_server/lib/language_server/server.ex
index 0f2d4c09b..4e16c0920 100644
--- a/apps/language_server/lib/language_server/server.ex
+++ b/apps/language_server/lib/language_server/server.ex
@@ -24,6 +24,7 @@ defmodule ElixirLS.LanguageServer.Server do
     Definition,
     Implementation,
     References,
+    Rename,
     Formatting,
     SignatureHelp,
     DocumentSymbols,
@@ -739,6 +740,26 @@ defmodule ElixirLS.LanguageServer.Server do
     {:async, fun, state}
   end
 
+  defp handle_request(rename_req(_id, uri, line, character, new_name), state = %__MODULE__{}) do
+    source_file = get_source_file(state, uri)
+
+    fun = fn ->
+      Rename.rename(source_file, uri, line + 1, character + 1, new_name)
+    end
+
+    {:async, fun, state}
+  end
+
+  defp handle_request(prepare_rename_req(_id, uri, line, character), state = %__MODULE__{}) do
+    source_file = get_source_file(state, uri)
+
+    fun = fn ->
+      Rename.prepare(source_file, uri, line + 1, character + 1)
+    end
+
+    {:async, fun, state}
+  end
+
   defp handle_request(execute_command_req(_id, command, args) = req, state = %__MODULE__{}) do
     {:async,
      fn ->
@@ -809,6 +830,7 @@ defmodule ElixirLS.LanguageServer.Server do
       "workspaceSymbolProvider" => true,
       "documentOnTypeFormattingProvider" => %{"firstTriggerCharacter" => "\n"},
       "codeLensProvider" => %{"resolveProvider" => false},
+      "renameProvider" => %{"prepareProvider" => true},
       "executeCommandProvider" => %{
         "commands" => ExecuteCommand.get_commands(server_instance_id)
       },
diff --git a/apps/language_server/test/providers/rename_test.exs b/apps/language_server/test/providers/rename_test.exs
new file mode 100644
index 000000000..ad3793c5b
--- /dev/null
+++ b/apps/language_server/test/providers/rename_test.exs
@@ -0,0 +1,213 @@
+defmodule ElixirLS.LanguageServer.Providers.RenameTest do
+  use ExUnit.Case, async: true
+
+  alias ElixirLS.LanguageServer.Providers.Rename
+  alias ElixirLS.LanguageServer.SourceFile
+  alias ElixirLS.LanguageServer.Test.FixtureHelpers
+  # mix cmd --app language_server mix test test/providers/rename_test.exs
+
+  @fake_uri "file:///World/Netherlands/Amsterdam/supercomputer/amazing.ex"
+
+  test "rename blank space" do
+    text = """
+    defmodule MyModule do
+      def hello() do
+        IO.inspect("hello world")
+      end
+    end
+    """
+
+    {line, char} = {2, 1}
+
+    assert {:ok, %{"documentChanges" => []}} =
+             Rename.rename(%SourceFile{text: text, version: 0}, @fake_uri, line, char, "test")
+  end
+
+  describe "renaming variable" do
+    test "a -> test" do
+      text = """
+      defmodule MyModule do
+        def add(a, b) do
+          a + b
+        end
+      end
+      """
+
+      # _a + b
+      {line, char} = {3, 5}
+
+      assert {:ok, %{"documentChanges" => changes}} =
+               Rename.rename(%SourceFile{text: text, version: 0}, @fake_uri, line, char, "test")
+
+      assert %{
+               "textDocument" => %{
+                 "uri" => @fake_uri,
+                 "version" => 1
+               },
+               "edits" => [
+                 %{
+                   "range" => %{end: %{character: 11, line: 1}, start: %{character: 10, line: 1}},
+                   "newText" => "test"
+                 },
+                 %{
+                   "range" => %{end: %{character: 5, line: 2}, start: %{character: 4, line: 2}},
+                   "newText" => "test"
+                 }
+               ]
+             } == List.first(changes)
+    end
+
+    test "nema -> name" do
+      text = """
+      defmodule MyModule do
+        def hello(nema) do
+          "Hello " <> nema
+        end
+      end
+      """
+
+      # "Hello " <> ne_ma
+      {line, char} = {3, 19}
+
+      assert {:ok, %{"documentChanges" => [changes]}} =
+               Rename.rename(
+                 %SourceFile{text: text, version: 0},
+                 @fake_uri,
+                 line,
+                 char,
+                 "name"
+               )
+
+      assert %{
+               "textDocument" => %{
+                 "uri" => @fake_uri,
+                 "version" => 1
+               },
+               "edits" => [
+                 %{
+                   "range" => %{end: %{character: 16, line: 1}, start: %{character: 12, line: 1}},
+                   "newText" => "name"
+                 },
+                 %{
+                   "range" => %{end: %{character: 20, line: 2}, start: %{character: 16, line: 2}},
+                   "newText" => "name"
+                 }
+               ]
+             } == changes
+    end
+  end
+
+  describe "renaming local function" do
+    test "create_message -> store_message" do
+      file_path = FixtureHelpers.get_path("rename_example.exs")
+      text = File.read!(file_path)
+      uri = SourceFile.path_to_uri(file_path)
+
+      # |> _create_message
+      {line, char} = {28, 8}
+
+      assert {:ok, %{"documentChanges" => [changes]}} =
+               Rename.rename(
+                 %SourceFile{text: text, version: 0},
+                 uri,
+                 line,
+                 char,
+                 "store_message"
+               )
+
+      assert %{
+               "textDocument" => %{
+                 "uri" => uri,
+                 "version" => 1
+               },
+               "edits" => [
+                 %{
+                   "newText" => "store_message",
+                   "range" => %{end: %{character: 21, line: 43}, start: %{character: 7, line: 43}}
+                 },
+                 %{
+                   "newText" => "store_message",
+                   "range" => %{end: %{character: 21, line: 27}, start: %{character: 7, line: 27}}
+                 }
+               ]
+             } == changes
+    end
+  end
+
+  describe "not yet (fully) supported/working renaming cases" do
+    test "rename started with cursor at function definition" do
+      file_path = FixtureHelpers.get_path("rename_example.exs")
+      text = File.read!(file_path)
+      uri = SourceFile.path_to_uri(file_path)
+
+      # defp _handle_error({:ok, message})
+      {line, char} = {4, 8}
+
+      assert {:ok, %{"documentChanges" => changes}} =
+               Rename.rename(
+                 %SourceFile{text: text, version: 0},
+                 uri,
+                 line,
+                 char,
+                 "handle_errors"
+               )
+
+      refute %{
+               "textDocument" => %{
+                 "uri" => uri,
+                 "version" => 1
+               },
+               "edits" => [
+                 %{
+                   "newText" => "handle_errors",
+                   "range" => %{end: %{character: 19, line: 37}, start: %{character: 7, line: 37}}
+                 },
+                 %{
+                   "newText" => "handle_errors",
+                   "range" => %{end: %{character: 19, line: 39}, start: %{character: 7, line: 39}}
+                 },
+                 %{
+                   "newText" => "handle_errors",
+                   "range" => %{end: %{character: 19, line: 28}, start: %{character: 7, line: 28}}
+                 }
+               ]
+             } == List.first(changes)
+    end
+
+    test "rename function with multiple heads" do
+      file_path = FixtureHelpers.get_path("rename_example.exs")
+      text = File.read!(file_path)
+      uri = SourceFile.path_to_uri(file_path)
+
+      # |> _handle_error
+      {line, char} = {29, 8}
+
+      assert {:ok, %{"documentChanges" => [changes]}} =
+               Rename.rename(
+                 %SourceFile{text: text, version: 0},
+                 uri,
+                 line,
+                 char,
+                 "handle_errors"
+               )
+
+      # missed second function head on line 40: handle_error({:error, changeset})
+      assert %{
+               "textDocument" => %{
+                 "uri" => uri,
+                 "version" => 1
+               },
+               "edits" => [
+                 %{
+                   "newText" => "handle_errors",
+                   "range" => %{end: %{character: 19, line: 37}, start: %{character: 7, line: 37}}
+                 },
+                 %{
+                   "newText" => "handle_errors",
+                   "range" => %{end: %{character: 19, line: 28}, start: %{character: 7, line: 28}}
+                 }
+               ]
+             } == changes
+    end
+  end
+end
diff --git a/apps/language_server/test/support/fixtures/rename_example.exs b/apps/language_server/test/support/fixtures/rename_example.exs
new file mode 100644
index 000000000..35c3a57be
--- /dev/null
+++ b/apps/language_server/test/support/fixtures/rename_example.exs
@@ -0,0 +1,67 @@
+defmodule Example.Pipeline do
+  use Broadway
+
+  alias Broadway.Message
+
+  def start_link(_) do
+    {module, opts} = Application.get_env(:broadway_sqs, :producer_module)
+
+    Broadway.start_link(__MODULE__,
+      name: __MODULE__,
+      producer: [
+        module: {module, opts}
+      ],
+      processors: [
+        default: []
+      ],
+      batchers: [
+        default: [
+          batch_size: 10,
+          batch_timeout: 2000
+        ]
+      ]
+    )
+  end
+
+  def handle_message(_, %Message{data: data} = message, _) do
+    info
+    |> create_message
+    |> handle_error
+
+    message
+  end
+
+  def handle_batch(_, messages, _, _) do
+    messages
+  end
+
+  defp handle_error({:ok, message}), do: message
+
+  defp handle_error({:error, changeset}) do
+    raise Example.SqsPipelineException, message: changeset.errors
+  end
+
+  defp create_message(data) do
+    data
+    |> Jason.decode(save_message)
+    |> prepare_params
+    |> save_message
+  end
+
+  defp save_message({:ok, params}) do
+    %Collector.Message{}
+    |> Collector.Message.changeset(params)
+    |> Collector.Repo.insert()
+  end
+
+  defp prepare_params({:ok, %{"action" => _, "payload" => _}} = params),
+    do: params
+
+  defp prepare_params(_) do
+    raise Example.PipelineException, message: "Message does not contain all necessary keys."
+  end
+end
+
+defmodule Example.PipelineException do
+  defexception [:message]
+end
\ No newline at end of file

From 2e769851d3fc62638225c0399c17f250981deb5d Mon Sep 17 00:00:00 2001
From: Tim Gent <tim.gent@multiverse.io>
Date: Thu, 20 Oct 2022 16:50:13 +0100
Subject: [PATCH 2/4] Fix renaming functions with multiple headers

---
 .../lib/language_server/providers/rename.ex   | 64 ++++++++++++++-----
 .../test/providers/rename_test.exs            | 36 ++++++-----
 2 files changed, 67 insertions(+), 33 deletions(-)

diff --git a/apps/language_server/lib/language_server/providers/rename.ex b/apps/language_server/lib/language_server/providers/rename.ex
index 2c31af2bb..5f524fe12 100644
--- a/apps/language_server/lib/language_server/providers/rename.ex
+++ b/apps/language_server/lib/language_server/providers/rename.ex
@@ -6,7 +6,6 @@ defmodule ElixirLS.LanguageServer.Providers.Rename do
   """
 
   alias ElixirLS.LanguageServer.SourceFile
-  #import ElixirLS.LanguageServer.Protocol
 
   def rename(%SourceFile{} = source_file, start_uri, line, character, new_name) do
     edits =
@@ -15,23 +14,24 @@ defmodule ElixirLS.LanguageServer.Providers.Rename do
            %ElixirSense.Location{} = definition <-
              ElixirSense.definition(source_file.text, line, character),
            references <- ElixirSense.references(source_file.text, line, character) do
- 
-
         length_old = length(char_ident)
 
-        [
-          %{
-            uri: start_uri,
-            range:
-              adjust_range(
-                definition.line,
-                definition.column,
-                definition.line,
-                definition.column + length_old
+        definition_references =
+          case definition do
+            %{type: :function} ->
+              parse_definition_source_code(definition, source_file.text)
+              |> get_all_fn_header_positions(char_ident)
+              |> positions_to_references(start_uri, length_old)
+
+            _ ->
+              positions_to_references(
+                [{definition.line, definition.column}],
+                start_uri,
+                length_old
               )
-          }
-          | repack_references(references, start_uri)
-        ]
+          end
+
+        definition_references ++ repack_references(references, start_uri)
       else
         _ ->
           []
@@ -62,7 +62,9 @@ defmodule ElixirLS.LanguageServer.Providers.Rename do
              begin: {start_line, start_col},
              end: {end_line, end_col},
              context: {context, char_ident}
-           } when context in [:local_or_var, :local_call] <- Code.Fragment.surround_context(source_file.text, {line, character}) do
+           }
+           when context in [:local_or_var, :local_call] <-
+             Code.Fragment.surround_context(source_file.text, {line, character}) do
         %{
           range: adjust_range(start_line, start_col, end_line, end_col),
           placeholder: to_string(char_ident)
@@ -91,6 +93,36 @@ defmodule ElixirLS.LanguageServer.Providers.Rename do
     end
   end
 
+  defp parse_definition_source_code(definition, source_text)
+
+  defp parse_definition_source_code(%{file: nil}, source_text) do
+    ElixirSense.Core.Parser.parse_string(source_text, true, true, 0)
+  end
+
+  defp parse_definition_source_code(%{file: file}, _) do
+    ElixirSense.Core.Parser.parse_file(file, true, true, 0)
+  end
+
+  defp get_all_fn_header_positions(parsed_source, char_ident) do
+    parsed_source.mods_funs_to_positions
+    |> Map.filter(fn
+      {{_, fn_name, _}, _} -> Atom.to_charlist(fn_name) == char_ident
+    end)
+    |> Enum.flat_map(fn {_, %{positions: positions}} -> positions end)
+    |> Enum.uniq()
+  end
+
+  defp positions_to_references(header_positions, start_uri, length_old)
+       when is_list(header_positions) do
+    header_positions
+    |> Enum.map(fn {line, column} ->
+      %{
+        uri: start_uri,
+        range: adjust_range(line, column, line, column + length_old)
+      }
+    end)
+  end
+
   defp adjust_range(start_line, start_character, end_line, end_character) do
     %{
       start: %{line: start_line - 1, character: start_character - 1},
diff --git a/apps/language_server/test/providers/rename_test.exs b/apps/language_server/test/providers/rename_test.exs
index ad3793c5b..ffe51b1c5 100644
--- a/apps/language_server/test/providers/rename_test.exs
+++ b/apps/language_server/test/providers/rename_test.exs
@@ -132,18 +132,15 @@ defmodule ElixirLS.LanguageServer.Providers.RenameTest do
                ]
              } == changes
     end
-  end
 
-  describe "not yet (fully) supported/working renaming cases" do
-    test "rename started with cursor at function definition" do
+    test "rename function with multiple heads: handle_error -> handle_errors" do
       file_path = FixtureHelpers.get_path("rename_example.exs")
       text = File.read!(file_path)
       uri = SourceFile.path_to_uri(file_path)
 
-      # defp _handle_error({:ok, message})
-      {line, char} = {4, 8}
+      {line, char} = {29, 8}
 
-      assert {:ok, %{"documentChanges" => changes}} =
+      assert {:ok, %{"documentChanges" => [changes]}} =
                Rename.rename(
                  %SourceFile{text: text, version: 0},
                  uri,
@@ -152,7 +149,7 @@ defmodule ElixirLS.LanguageServer.Providers.RenameTest do
                  "handle_errors"
                )
 
-      refute %{
+      assert %{
                "textDocument" => %{
                  "uri" => uri,
                  "version" => 1
@@ -160,29 +157,31 @@ defmodule ElixirLS.LanguageServer.Providers.RenameTest do
                "edits" => [
                  %{
                    "newText" => "handle_errors",
-                   "range" => %{end: %{character: 19, line: 37}, start: %{character: 7, line: 37}}
+                   "range" => %{end: %{character: 19, line: 39}, start: %{character: 7, line: 39}}
                  },
                  %{
                    "newText" => "handle_errors",
-                   "range" => %{end: %{character: 19, line: 39}, start: %{character: 7, line: 39}}
+                   "range" => %{end: %{character: 19, line: 37}, start: %{character: 7, line: 37}}
                  },
                  %{
                    "newText" => "handle_errors",
                    "range" => %{end: %{character: 19, line: 28}, start: %{character: 7, line: 28}}
                  }
                ]
-             } == List.first(changes)
+             } == changes
     end
+  end
 
-    test "rename function with multiple heads" do
+  describe "not yet (fully) supported/working renaming cases" do
+    test "rename started with cursor at function definition" do
       file_path = FixtureHelpers.get_path("rename_example.exs")
       text = File.read!(file_path)
       uri = SourceFile.path_to_uri(file_path)
 
-      # |> _handle_error
-      {line, char} = {29, 8}
+      # defp _handle_error({:ok, message})
+      {line, char} = {4, 8}
 
-      assert {:ok, %{"documentChanges" => [changes]}} =
+      assert {:ok, %{"documentChanges" => changes}} =
                Rename.rename(
                  %SourceFile{text: text, version: 0},
                  uri,
@@ -191,8 +190,7 @@ defmodule ElixirLS.LanguageServer.Providers.RenameTest do
                  "handle_errors"
                )
 
-      # missed second function head on line 40: handle_error({:error, changeset})
-      assert %{
+      refute %{
                "textDocument" => %{
                  "uri" => uri,
                  "version" => 1
@@ -202,12 +200,16 @@ defmodule ElixirLS.LanguageServer.Providers.RenameTest do
                    "newText" => "handle_errors",
                    "range" => %{end: %{character: 19, line: 37}, start: %{character: 7, line: 37}}
                  },
+                 %{
+                   "newText" => "handle_errors",
+                   "range" => %{end: %{character: 19, line: 39}, start: %{character: 7, line: 39}}
+                 },
                  %{
                    "newText" => "handle_errors",
                    "range" => %{end: %{character: 19, line: 28}, start: %{character: 7, line: 28}}
                  }
                ]
-             } == changes
+             } == List.first(changes)
     end
   end
 end

From 1daf1c8ef52ff1486ce9384aa75e3c0fc7bcbfce Mon Sep 17 00:00:00 2001
From: Tim Gent <tim.gent@multiverse.io>
Date: Fri, 21 Oct 2022 10:47:26 +0100
Subject: [PATCH 3/4] Simplify tests with rename_example - Make rename_example
 a `.ex` file so we can later test multi-file   refactors - Simplify
 rename_example to make it easier to follow - Extract some common patterns out
 in the tests

---
 .../test/providers/rename_test.exs            | 220 +++++++++---------
 .../test/support/fixtures/rename_example.ex   |  15 ++
 .../test/support/fixtures/rename_example.exs  |  67 ------
 3 files changed, 128 insertions(+), 174 deletions(-)
 create mode 100644 apps/language_server/test/support/fixtures/rename_example.ex
 delete mode 100644 apps/language_server/test/support/fixtures/rename_example.exs

diff --git a/apps/language_server/test/providers/rename_test.exs b/apps/language_server/test/providers/rename_test.exs
index ffe51b1c5..c20a9b563 100644
--- a/apps/language_server/test/providers/rename_test.exs
+++ b/apps/language_server/test/providers/rename_test.exs
@@ -36,25 +36,18 @@ defmodule ElixirLS.LanguageServer.Providers.RenameTest do
       # _a + b
       {line, char} = {3, 5}
 
-      assert {:ok, %{"documentChanges" => changes}} =
-               Rename.rename(%SourceFile{text: text, version: 0}, @fake_uri, line, char, "test")
-
-      assert %{
-               "textDocument" => %{
-                 "uri" => @fake_uri,
-                 "version" => 1
-               },
-               "edits" => [
-                 %{
-                   "range" => %{end: %{character: 11, line: 1}, start: %{character: 10, line: 1}},
-                   "newText" => "test"
-                 },
-                 %{
-                   "range" => %{end: %{character: 5, line: 2}, start: %{character: 4, line: 2}},
-                   "newText" => "test"
-                 }
-               ]
-             } == List.first(changes)
+      edits =
+        Rename.rename(%SourceFile{text: text, version: 0}, @fake_uri, line, char, "test")
+        |> assert_return_structure_and_get_edits(@fake_uri, 1)
+
+      expected_edits =
+        [
+          %{line: 1, start_char: 10, end_char: 11},
+          %{line: 2, start_char: 4, end_char: 5}
+        ]
+        |> get_expected_edits("test")
+
+      assert sort_edit_by_start_line(edits) == expected_edits
     end
 
     test "nema -> name" do
@@ -69,112 +62,91 @@ defmodule ElixirLS.LanguageServer.Providers.RenameTest do
       # "Hello " <> ne_ma
       {line, char} = {3, 19}
 
-      assert {:ok, %{"documentChanges" => [changes]}} =
-               Rename.rename(
-                 %SourceFile{text: text, version: 0},
-                 @fake_uri,
-                 line,
-                 char,
-                 "name"
-               )
-
-      assert %{
-               "textDocument" => %{
-                 "uri" => @fake_uri,
-                 "version" => 1
-               },
-               "edits" => [
-                 %{
-                   "range" => %{end: %{character: 16, line: 1}, start: %{character: 12, line: 1}},
-                   "newText" => "name"
-                 },
-                 %{
-                   "range" => %{end: %{character: 20, line: 2}, start: %{character: 16, line: 2}},
-                   "newText" => "name"
-                 }
-               ]
-             } == changes
+      edits =
+        Rename.rename(
+          %SourceFile{text: text, version: 0},
+          @fake_uri,
+          line,
+          char,
+          "name"
+        )
+        |> assert_return_structure_and_get_edits(@fake_uri, 1)
+
+      expected_edits =
+        [
+          %{line: 1, start_char: 12, end_char: 16},
+          %{line: 2, start_char: 16, end_char: 20}
+        ]
+        |> get_expected_edits("name")
+
+      assert sort_edit_by_start_line(edits) == expected_edits
     end
   end
 
   describe "renaming local function" do
-    test "create_message -> store_message" do
-      file_path = FixtureHelpers.get_path("rename_example.exs")
+    test "subtract -> new_subtract" do
+      file_path = FixtureHelpers.get_path("rename_example.ex")
       text = File.read!(file_path)
       uri = SourceFile.path_to_uri(file_path)
 
-      # |> _create_message
-      {line, char} = {28, 8}
-
-      assert {:ok, %{"documentChanges" => [changes]}} =
-               Rename.rename(
-                 %SourceFile{text: text, version: 0},
-                 uri,
-                 line,
-                 char,
-                 "store_message"
-               )
-
-      assert %{
-               "textDocument" => %{
-                 "uri" => uri,
-                 "version" => 1
-               },
-               "edits" => [
-                 %{
-                   "newText" => "store_message",
-                   "range" => %{end: %{character: 21, line: 43}, start: %{character: 7, line: 43}}
-                 },
-                 %{
-                   "newText" => "store_message",
-                   "range" => %{end: %{character: 21, line: 27}, start: %{character: 7, line: 27}}
-                 }
-               ]
-             } == changes
+      #     d = subtract(a, b)
+      {line, char} = {6, 10}
+
+      edits =
+        Rename.rename(
+          %SourceFile{text: text, version: 0},
+          uri,
+          line,
+          char,
+          "new_subtract"
+        )
+        |> assert_return_structure_and_get_edits(uri, 1)
+
+      expected_edits =
+        [
+          %{line: 5, start_char: 8, end_char: 16},
+          %{line: 13, start_char: 7, end_char: 15}
+        ]
+        |> get_expected_edits("new_subtract")
+
+      assert sort_edit_by_start_line(edits) == expected_edits
     end
 
     test "rename function with multiple heads: handle_error -> handle_errors" do
-      file_path = FixtureHelpers.get_path("rename_example.exs")
+      file_path = FixtureHelpers.get_path("rename_example.ex")
       text = File.read!(file_path)
       uri = SourceFile.path_to_uri(file_path)
 
-      {line, char} = {29, 8}
-
-      assert {:ok, %{"documentChanges" => [changes]}} =
-               Rename.rename(
-                 %SourceFile{text: text, version: 0},
-                 uri,
-                 line,
-                 char,
-                 "handle_errors"
-               )
-
-      assert %{
-               "textDocument" => %{
-                 "uri" => uri,
-                 "version" => 1
-               },
-               "edits" => [
-                 %{
-                   "newText" => "handle_errors",
-                   "range" => %{end: %{character: 19, line: 39}, start: %{character: 7, line: 39}}
-                 },
-                 %{
-                   "newText" => "handle_errors",
-                   "range" => %{end: %{character: 19, line: 37}, start: %{character: 7, line: 37}}
-                 },
-                 %{
-                   "newText" => "handle_errors",
-                   "range" => %{end: %{character: 19, line: 28}, start: %{character: 7, line: 28}}
-                 }
-               ]
-             } == changes
+      #     c = add(a, b)
+      {line, char} = {5, 9}
+
+      edits =
+        Rename.rename(
+          %SourceFile{text: text, version: 0},
+          uri,
+          line,
+          char,
+          "new_add"
+        )
+        |> assert_return_structure_and_get_edits(uri, 1)
+
+      expected_edits =
+        [
+          %{line: 4, start_char: 8, end_char: 11},
+          %{line: 6, start_char: 4, end_char: 7},
+          %{line: 9, start_char: 7, end_char: 10},
+          %{line: 10, start_char: 7, end_char: 10},
+          %{line: 11, start_char: 7, end_char: 10}
+        ]
+        |> get_expected_edits("new_add")
+
+      assert sort_edit_by_start_line(edits) == expected_edits
     end
   end
 
   describe "not yet (fully) supported/working renaming cases" do
     test "rename started with cursor at function definition" do
-      file_path = FixtureHelpers.get_path("rename_example.exs")
+      file_path = FixtureHelpers.get_path("rename_example.ex")
       text = File.read!(file_path)
       uri = SourceFile.path_to_uri(file_path)
 
@@ -212,4 +184,38 @@ defmodule ElixirLS.LanguageServer.Providers.RenameTest do
              } == List.first(changes)
     end
   end
+
+  defp get_expected_edits(edits, new_text) when is_list(edits),
+    do: Enum.map(edits, &get_expected_edits(&1, new_text))
+
+  defp get_expected_edits(%{line: line, start_char: start_char, end_char: end_char}, new_text) do
+    %{
+      "newText" => new_text,
+      "range" => %{
+        start: %{line: line, character: start_char},
+        end: %{line: line, character: end_char}
+      }
+    }
+  end
+
+  defp assert_return_structure_and_get_edits(rename_result, uri, version) do
+    assert {:ok,
+            %{
+              "documentChanges" => [
+                %{
+                  "textDocument" => %{
+                    "uri" => ^uri,
+                    "version" => ^version
+                  },
+                  "edits" => edits
+                }
+              ]
+            }} = rename_result
+
+    edits
+  end
+
+  defp sort_edit_by_start_line(edits) do
+    Enum.sort(edits, &(&1["range"].start.line < &2["range"].start.line))
+  end
 end
diff --git a/apps/language_server/test/support/fixtures/rename_example.ex b/apps/language_server/test/support/fixtures/rename_example.ex
new file mode 100644
index 000000000..df86abea5
--- /dev/null
+++ b/apps/language_server/test/support/fixtures/rename_example.ex
@@ -0,0 +1,15 @@
+defmodule ElixirLS.Test.RenameExample do
+  def main do
+    a = 5
+    b = 10
+    c = add(a, b)
+    d = subtract(a, b)
+    add(c, d)
+  end
+
+  defp add(a, b)
+  defp add(a, b) when is_integer(a) and is_integer(b), do: a + b
+  defp add(a, b) when is_binary(a) and is_binary(b), do: a <> b
+
+  defp subtract(a, b), do: a - b
+end
diff --git a/apps/language_server/test/support/fixtures/rename_example.exs b/apps/language_server/test/support/fixtures/rename_example.exs
deleted file mode 100644
index 35c3a57be..000000000
--- a/apps/language_server/test/support/fixtures/rename_example.exs
+++ /dev/null
@@ -1,67 +0,0 @@
-defmodule Example.Pipeline do
-  use Broadway
-
-  alias Broadway.Message
-
-  def start_link(_) do
-    {module, opts} = Application.get_env(:broadway_sqs, :producer_module)
-
-    Broadway.start_link(__MODULE__,
-      name: __MODULE__,
-      producer: [
-        module: {module, opts}
-      ],
-      processors: [
-        default: []
-      ],
-      batchers: [
-        default: [
-          batch_size: 10,
-          batch_timeout: 2000
-        ]
-      ]
-    )
-  end
-
-  def handle_message(_, %Message{data: data} = message, _) do
-    info
-    |> create_message
-    |> handle_error
-
-    message
-  end
-
-  def handle_batch(_, messages, _, _) do
-    messages
-  end
-
-  defp handle_error({:ok, message}), do: message
-
-  defp handle_error({:error, changeset}) do
-    raise Example.SqsPipelineException, message: changeset.errors
-  end
-
-  defp create_message(data) do
-    data
-    |> Jason.decode(save_message)
-    |> prepare_params
-    |> save_message
-  end
-
-  defp save_message({:ok, params}) do
-    %Collector.Message{}
-    |> Collector.Message.changeset(params)
-    |> Collector.Repo.insert()
-  end
-
-  defp prepare_params({:ok, %{"action" => _, "payload" => _}} = params),
-    do: params
-
-  defp prepare_params(_) do
-    raise Example.PipelineException, message: "Message does not contain all necessary keys."
-  end
-end
-
-defmodule Example.PipelineException do
-  defexception [:message]
-end
\ No newline at end of file

From 987456e9db68280103840d31588ad04897fd2f4c Mon Sep 17 00:00:00 2001
From: Tim Gent <tim.gent@multiverse.io>
Date: Fri, 21 Oct 2022 12:22:22 +0100
Subject: [PATCH 4/4] Implement rename across multiple files

---
 .../lib/language_server/providers/rename.ex   | 31 +++++++----
 .../test/providers/rename_test.exs            | 52 ++++++++++++++++++-
 .../test/support/fixtures/rename_example.ex   |  2 +-
 .../test/support/fixtures/rename_example_b.ex |  3 ++
 4 files changed, 76 insertions(+), 12 deletions(-)
 create mode 100644 apps/language_server/test/support/fixtures/rename_example_b.ex

diff --git a/apps/language_server/lib/language_server/providers/rename.ex b/apps/language_server/lib/language_server/providers/rename.ex
index 5f524fe12..2897e9d9b 100644
--- a/apps/language_server/lib/language_server/providers/rename.ex
+++ b/apps/language_server/lib/language_server/providers/rename.ex
@@ -9,8 +9,8 @@ defmodule ElixirLS.LanguageServer.Providers.Rename do
 
   def rename(%SourceFile{} = source_file, start_uri, line, character, new_name) do
     edits =
-      with %{context: {context, char_ident}} when context in [:local_or_var, :local_call] <-
-             Code.Fragment.surround_context(source_file.text, {line, character}),
+      with char_ident when not is_nil(char_ident) <-
+             get_char_ident(source_file.text, line, character),
            %ElixirSense.Location{} = definition <-
              ElixirSense.definition(source_file.text, line, character),
            references <- ElixirSense.references(source_file.text, line, character) do
@@ -18,11 +18,16 @@ defmodule ElixirLS.LanguageServer.Providers.Rename do
 
         definition_references =
           case definition do
-            %{type: :function} ->
-              parse_definition_source_code(definition, source_file.text)
+            %{file: nil, type: :function} ->
+              parse_definition_source_code(source_file.text)
               |> get_all_fn_header_positions(char_ident)
               |> positions_to_references(start_uri, length_old)
 
+            %{file: separate_file_path, type: :function} ->
+              parse_definition_source_code(definition)
+              |> get_all_fn_header_positions(char_ident)
+              |> positions_to_references(SourceFile.path_to_uri(separate_file_path), length_old)
+
             _ ->
               positions_to_references(
                 [{definition.line, definition.column}],
@@ -93,14 +98,12 @@ defmodule ElixirLS.LanguageServer.Providers.Rename do
     end
   end
 
-  defp parse_definition_source_code(definition, source_text)
-
-  defp parse_definition_source_code(%{file: nil}, source_text) do
-    ElixirSense.Core.Parser.parse_string(source_text, true, true, 0)
+  defp parse_definition_source_code(%{file: file}) do
+    ElixirSense.Core.Parser.parse_file(file, true, true, 0)
   end
 
-  defp parse_definition_source_code(%{file: file}, _) do
-    ElixirSense.Core.Parser.parse_file(file, true, true, 0)
+  defp parse_definition_source_code(source_text) when is_binary(source_text) do
+    ElixirSense.Core.Parser.parse_string(source_text, true, true, 0)
   end
 
   defp get_all_fn_header_positions(parsed_source, char_ident) do
@@ -129,4 +132,12 @@ defmodule ElixirLS.LanguageServer.Providers.Rename do
       end: %{line: end_line - 1, character: end_character - 1}
     }
   end
+
+  defp get_char_ident(text, line, character) do
+    case Code.Fragment.surround_context(text, {line, character}) do
+      %{context: {context, char_ident}} when context in [:local_or_var, :local_call] -> char_ident
+      %{context: {:dot, _, char_ident}} -> char_ident
+      _ -> nil
+    end
+  end
 end
diff --git a/apps/language_server/test/providers/rename_test.exs b/apps/language_server/test/providers/rename_test.exs
index c20a9b563..934ac38a3 100644
--- a/apps/language_server/test/providers/rename_test.exs
+++ b/apps/language_server/test/providers/rename_test.exs
@@ -112,7 +112,7 @@ defmodule ElixirLS.LanguageServer.Providers.RenameTest do
       assert sort_edit_by_start_line(edits) == expected_edits
     end
 
-    test "rename function with multiple heads: handle_error -> handle_errors" do
+    test "rename function with multiple heads: add -> new_add" do
       file_path = FixtureHelpers.get_path("rename_example.ex")
       text = File.read!(file_path)
       uri = SourceFile.path_to_uri(file_path)
@@ -142,6 +142,56 @@ defmodule ElixirLS.LanguageServer.Providers.RenameTest do
 
       assert sort_edit_by_start_line(edits) == expected_edits
     end
+
+    test "rename function defined in a different file ten -> new_ten" do
+      file_path = FixtureHelpers.get_path("rename_example.ex")
+      text = File.read!(file_path)
+      uri = SourceFile.path_to_uri(file_path)
+
+      fn_definition_file_uri =
+        FixtureHelpers.get_path("rename_example_b.ex") |> SourceFile.path_to_uri()
+
+      #     b = ElixirLS.Test.RenameExampleB.ten()
+      {line, char} = {4, 38}
+
+      assert {:ok,
+              %{
+                "documentChanges" => [
+                  %{
+                    "textDocument" => %{
+                      "uri" => ^uri,
+                      "version" => 1
+                    },
+                    "edits" => file_edits
+                  },
+                  %{
+                    "textDocument" => %{
+                      "uri" => ^fn_definition_file_uri,
+                      "version" => 1
+                    },
+                    "edits" => fn_definition_file_edits
+                  }
+                ]
+              }} =
+               Rename.rename(
+                 %SourceFile{text: text, version: 0},
+                 uri,
+                 line,
+                 char,
+                 "new_ten"
+               )
+
+      expected_edits_fn_definition_file =
+        [%{line: 1, start_char: 6, end_char: 9}] |> get_expected_edits("new_ten")
+
+      assert sort_edit_by_start_line(fn_definition_file_edits) ==
+               expected_edits_fn_definition_file
+
+      expected_edits = [%{line: 3, start_char: 37, end_char: 40}] |> get_expected_edits("new_ten")
+
+      assert sort_edit_by_start_line(file_edits) ==
+               expected_edits
+    end
   end
 
   describe "not yet (fully) supported/working renaming cases" do
diff --git a/apps/language_server/test/support/fixtures/rename_example.ex b/apps/language_server/test/support/fixtures/rename_example.ex
index df86abea5..2110e22a3 100644
--- a/apps/language_server/test/support/fixtures/rename_example.ex
+++ b/apps/language_server/test/support/fixtures/rename_example.ex
@@ -1,7 +1,7 @@
 defmodule ElixirLS.Test.RenameExample do
   def main do
     a = 5
-    b = 10
+    b = ElixirLS.Test.RenameExampleB.ten()
     c = add(a, b)
     d = subtract(a, b)
     add(c, d)
diff --git a/apps/language_server/test/support/fixtures/rename_example_b.ex b/apps/language_server/test/support/fixtures/rename_example_b.ex
new file mode 100644
index 000000000..06839db1d
--- /dev/null
+++ b/apps/language_server/test/support/fixtures/rename_example_b.ex
@@ -0,0 +1,3 @@
+defmodule ElixirLS.Test.RenameExampleB do
+  def ten, do: 10
+end