vim-patch:8.2.4160: cannot change the register used for Select mode delete

Problem:    Cannot change the register used for Select mode delete.
Solution:   Make CTRL-R set the register to be used when deleting text for
            Select mode. (Shougo Matsushita, closes vim/vim#9531)
https://github.com/vim/vim/commit/4ede01f18884961f2e008880b4964e5d61ea5c36

1 files changed, 23 insertions, 5 deletions

diff --git a/src/nvim/normal.c b/src/nvim/normal.c
index 2b5b47c0b3..2fce3e10b8 100644
--- a/src/nvim/normal.c
+++ b/src/nvim/normal.c
@@ -164,7 +164,7 @@ static const struct nv_cmd {
   { Ctrl_O,    nv_ctrlo,       0,                      0 },
   { Ctrl_P,    nv_up,          NV_STS,                 false },
   { Ctrl_Q,    nv_visual,      0,                      false },
-  { Ctrl_R,    nv_redo,        0,                      0 },
+  { Ctrl_R,    nv_redo_or_register, 0,                      0 },
   { Ctrl_S,    nv_ignore,      0,                      0 },
   { Ctrl_T,    nv_tagpop,      NV_NCW,                 0 },
   { Ctrl_U,    nv_halfpage,    0,                      0 },
@@ -961,6 +961,7 @@ normal_end:
       && s->oa.regname == 0) {
     if (restart_VIsual_select == 1) {
       VIsual_select = true;
+      VIsual_select_reg = 0;
       trigger_modechanged();
       showmode();
       restart_VIsual_select = 0;
@@ -6186,6 +6187,7 @@ static void nv_g_cmd(cmdarg_T *cap)
       // start Select mode.
       if (cap->arg) {
         VIsual_select = true;
+        VIsual_select_reg = 0;
       } else {
         may_start_select('c');
       }
@@ -6698,11 +6700,26 @@ static void nv_dot(cmdarg_T *cap)
   }
 }
 
-/*
- * CTRL-R: undo undo
- */
-static void nv_redo(cmdarg_T *cap)
+// CTRL-R: undo undo or specify register in select mode
+static void nv_redo_or_register(cmdarg_T *cap)
 {
+  if (VIsual_select && VIsual_active) {
+    int reg;
+    // Get register name
+    no_mapping++;
+    reg = plain_vgetc();
+    LANGMAP_ADJUST(reg, true);
+    no_mapping--;
+
+    if (reg == '"') {
+      // the unnamed register is 0
+      reg = 0;
+    }
+
+    VIsual_select_reg = valid_yank_reg(reg, true) ? reg : 0;
+    return;
+  }
+
   if (!checkclearopq(cap->oap)) {
     u_redo((int)cap->count1);
     curwin->w_set_curswant = true;
@@ -7023,6 +7040,7 @@ static void nv_select(cmdarg_T *cap)
 {
   if (VIsual_active) {
     VIsual_select = true;
+    VIsual_select_reg = 0;
   } else if (VIsual_reselect) {
     cap->nchar = 'v';               // fake "gv" command
     cap->arg = true;