From 554d7b98893b47faccfe35908de02e1ab4270ab5 Mon Sep 17 00:00:00 2001
From: Lukasz Samson <lukaszsamson@gmail.com>
Date: Thu, 8 Feb 2024 00:21:10 +0100
Subject: [PATCH] fix an edge case when reduced range may no longer contain
 cursor

---
 .../providers/selection_ranges.ex             | 25 ++++----
 .../lib/language_server/range_utils.ex        |  5 ++
 .../test/providers/selection_ranges_test.exs  | 64 +++++++++++++++++++
 3 files changed, 83 insertions(+), 11 deletions(-)

diff --git a/apps/language_server/lib/language_server/providers/selection_ranges.ex b/apps/language_server/lib/language_server/providers/selection_ranges.ex
index b4f3529b8..e2937ffe5 100644
--- a/apps/language_server/lib/language_server/providers/selection_ranges.ex
+++ b/apps/language_server/lib/language_server/providers/selection_ranges.ex
@@ -188,8 +188,9 @@ defmodule ElixirLS.LanguageServer.Providers.SelectionRanges do
           {_, {start_line, start_character, _}, _} = previous_token
           {_, {end_line, end_character, _}, _} = token
 
-          if (start_line < line or (start_line == line and start_character <= character)) and
-               (end_line > line or (end_line == line and end_character >= character)) do
+          range_between_stop_tokens = range(start_line, start_character, end_line, end_character)
+
+          if in?(range_between_stop_tokens, {line, character}) do
             # dbg({previous_token, after_previous, before_stop, token})
             {end_line, end_character} =
               case before_stop do
@@ -225,15 +226,17 @@ defmodule ElixirLS.LanguageServer.Providers.SelectionRanges do
                   {start_line, start_character}
               end
 
-            # TODO
-            {:halt,
-             {token_tuple,
-              [
-                intersection(
-                  range(start_line, start_character, end_line, end_character),
-                  inner_range
-                )
-              ]}}
+            trimmed_range =
+              intersection(
+                range(start_line, start_character, end_line, end_character),
+                inner_range
+              )
+
+            if in?(trimmed_range, {line, character}) do
+              {:halt, {token_tuple, [trimmed_range]}}
+            else
+              {:halt, {token_tuple, []}}
+            end
           else
             {:cont, {token_tuple, []}}
           end
diff --git a/apps/language_server/lib/language_server/range_utils.ex b/apps/language_server/lib/language_server/range_utils.ex
index b410b54a2..b99fec638 100644
--- a/apps/language_server/lib/language_server/range_utils.ex
+++ b/apps/language_server/lib/language_server/range_utils.ex
@@ -15,6 +15,11 @@ defmodule ElixirLS.LanguageServer.RangeUtils do
     range(0, 0, Enum.count(lines) - 1, utf8_size)
   end
 
+  def in?(range(start_line, start_character, end_line, end_character), {line, character}) do
+    (start_line < line or (start_line == line and start_character <= character)) and
+      (end_line > line or (end_line == line and end_character >= character))
+  end
+
   def valid?(range(start_line, start_character, end_line, end_character))
       when is_integer(start_line) and is_integer(end_line) and is_integer(start_character) and
              is_integer(end_character) do
diff --git a/apps/language_server/test/providers/selection_ranges_test.exs b/apps/language_server/test/providers/selection_ranges_test.exs
index d2b7dd0bb..fd1514c7e 100644
--- a/apps/language_server/test/providers/selection_ranges_test.exs
+++ b/apps/language_server/test/providers/selection_ranges_test.exs
@@ -996,4 +996,68 @@ defmodule ElixirLS.LanguageServer.Providers.SelectionRangesTest do
       assert_range(ranges, range(0, 6, 2, 6))
     end
   end
+
+  describe "map update" do
+    test "left side of |" do
+      text = """
+      %{asd | a: 1, b: x}
+      """
+
+      ranges = get_ranges(text, 0, 3)
+
+      # full range
+      assert_range(ranges, range(0, 0, 1, 0))
+      # full map
+      assert_range(ranges, range(0, 0, 0, 19))
+      # asd
+      assert_range(ranges, range(0, 2, 0, 5))
+    end
+
+    test "right side of |" do
+      text = """
+      %{asd | a: 1, b: x}
+      """
+
+      ranges = get_ranges(text, 0, 9)
+
+      # full range
+      assert_range(ranges, range(0, 0, 1, 0))
+      # full map
+      assert_range(ranges, range(0, 0, 0, 19))
+      # full keyword
+      assert_range(ranges, range(0, 8, 0, 18))
+      # a: 1
+      assert_range(ranges, range(0, 8, 0, 12))
+    end
+
+    test "left side of | near" do
+      text = """
+      %{state | 1 => 1, counter: counter + to_dispatch, demand: demand - to_dispatch}
+      """
+
+      ranges = get_ranges(text, 0, 8)
+
+      # full range
+      assert_range(ranges, range(0, 0, 1, 0))
+      # full map
+      assert_range(ranges, range(0, 0, 0, 79))
+      # |
+      assert_range(ranges, range(0, 8, 0, 9))
+    end
+
+    test "right side of | near" do
+      text = """
+      %{state | 1 => 1, counter: counter + to_dispatch, demand: demand - to_dispatch}
+      """
+
+      ranges = get_ranges(text, 0, 9)
+
+      # full range
+      assert_range(ranges, range(0, 0, 1, 0))
+      # full map
+      assert_range(ranges, range(0, 0, 0, 79))
+      # |
+      assert_range(ranges, range(0, 8, 0, 9))
+    end
+  end
 end