fix(keycodes): simplify S- properly when D- is present (#27316)

2 files changed, 21 insertions, 4 deletions

diff --git a/src/nvim/keycodes.c b/src/nvim/keycodes.c
index c45ad83204..c910d0955a 100644
--- a/src/nvim/keycodes.c
+++ b/src/nvim/keycodes.c
@@ -758,17 +758,20 @@ static int extract_modifiers(int key, int *modp, const bool simplify, bool *cons
 {
   int modifiers = *modp;
 
-  // Command-key and ctrl are special
-  if (!(modifiers & MOD_MASK_CMD) && !(modifiers & MOD_MASK_CTRL)) {
-    if ((modifiers & MOD_MASK_SHIFT) && ASCII_ISALPHA(key)) {
-      key = TOUPPER_ASC(key);
+  if ((modifiers & MOD_MASK_SHIFT) && ASCII_ISALPHA(key)) {
+    key = TOUPPER_ASC(key);
+    // With <C-S-a> we keep the shift modifier.
+    // With <S-a>, <A-S-a> and <S-A> we don't keep the shift modifier.
+    if (!(modifiers & MOD_MASK_CTRL)) {
       modifiers &= ~MOD_MASK_SHIFT;
     }
   }
+
   // <C-H> and <C-h> mean the same thing, always use "H"
   if ((modifiers & MOD_MASK_CTRL) && ASCII_ISALPHA(key)) {
     key = TOUPPER_ASC(key);
   }
+
   if (simplify && (modifiers & MOD_MASK_CTRL)
       && ((key >= '?' && key <= '_') || ASCII_ISALPHA(key))) {
     key = CTRL_CHR(key);
diff --git a/test/functional/ui/input_spec.lua b/test/functional/ui/input_spec.lua
index 80862b668f..b2899bf82d 100644
--- a/test/functional/ui/input_spec.lua
+++ b/test/functional/ui/input_spec.lua
@@ -29,6 +29,10 @@ describe('mappings', function()
   end
 
   before_each(function()
+    add_mapping('<A-l>', '<A-l>')
+    add_mapping('<A-L>', '<A-L>')
+    add_mapping('<D-l>', '<D-l>')
+    add_mapping('<D-L>', '<D-L>')
     add_mapping('<C-L>', '<C-L>')
     add_mapping('<C-S-L>', '<C-S-L>')
     add_mapping('<s-up>', '<s-up>')
@@ -61,7 +65,17 @@ describe('mappings', function()
   end)
 
   it('ok', function()
+    check_mapping('<A-l>', '<A-l>')
+    check_mapping('<A-L>', '<A-L>')
+    check_mapping('<A-S-l>', '<A-L>')
+    check_mapping('<A-S-L>', '<A-L>')
+    check_mapping('<D-l>', '<D-l>')
+    check_mapping('<D-L>', '<D-L>')
+    check_mapping('<D-S-l>', '<D-L>')
+    check_mapping('<D-S-L>', '<D-L>')
+    check_mapping('<C-l>', '<C-L>')
     check_mapping('<C-L>', '<C-L>')
+    check_mapping('<C-S-l>', '<C-S-L>')
     check_mapping('<C-S-L>', '<C-S-L>')
     check_mapping('<s-up>', '<s-up>')
     check_mapping('<c-s-up>', '<c-s-up>')