From fb9dbfed2a903fbf38f37db904c960d69973fb8b Mon Sep 17 00:00:00 2001
From: Maxime Coste <mawww@kakoune.org>
Date: Fri, 28 May 2021 20:15:56 +1000
Subject: [PATCH] Canonicalize <s-ascii> into uppercase in csi key parsing code

Fixes #4159
---
 src/ncurses_ui.cc | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/src/ncurses_ui.cc b/src/ncurses_ui.cc
index 18be7bd2..31c5269a 100644
--- a/src/ncurses_ui.cc
+++ b/src/ncurses_ui.cc
@@ -725,7 +725,13 @@ Optional<Key> NCursesUI::get_next_key()
 
         auto masked_key = [&](Codepoint key) {
             int mask = std::max(params[1] - 1, 0);
-            return Key{parse_mask(mask), key};
+            Key::Modifiers modifiers = parse_mask(mask);
+            if (is_basic_alpha(key) and (modifiers & Key::Modifiers::Shift))
+            {
+                modifiers &= ~Key::Modifiers::Shift;
+                key = to_upper(key);
+            }
+            return Key{modifiers, key};
         };
 
         switch (c)