vim-patch:8.2.3748: giving an error for an empty sign argument breaks a plugin

Problem:    Giving an error for an empty sign argument breaks a plugin.
Solution:   Do not give an error.
https://github.com/vim/vim/commit/e5710a02cb78c2a0a868ea55740835c78ddecbb4

3 files changed, 0 insertions, 35 deletions

diff --git a/src/nvim/globals.h b/src/nvim/globals.h
index 46506a59cb..b2422fd531 100644
--- a/src/nvim/globals.h
+++ b/src/nvim/globals.h
@@ -997,8 +997,6 @@ EXTERN char e_non_empty_string_required[] INIT(= N_("E1142: Non-empty string req
 
 EXTERN char e_cannot_define_autocommands_for_all_events[] INIT(= N_("E1155: Cannot define autocommands for ALL events"));
 
-EXTERN char e_group_name_missing_for_str[] INIT(= N_("E1249: Group name missing for %s"));
-
 EXTERN char top_bot_msg[] INIT(= N_("search hit TOP, continuing at BOTTOM"));
 EXTERN char bot_top_msg[] INIT(= N_("search hit BOTTOM, continuing at TOP"));
 
diff --git a/src/nvim/sign.c b/src/nvim/sign.c
index 8409c07439..32be714184 100644
--- a/src/nvim/sign.c
+++ b/src/nvim/sign.c
@@ -1148,15 +1148,6 @@ linenr_T sign_jump(int sign_id, char_u *sign_group, buf_T *buf)
   return lnum;
 }
 
-static int check_empty_group(size_t len, char *name)
-{
-  if (len == 0) {
-    semsg(_(e_group_name_missing_for_str), name);
-    return FAIL;
-  }
-  return OK;
-}
-
 /// ":sign define {name} ..." command
 static void sign_define_cmd(char_u *sign_name, char_u *cmdline)
 {
@@ -1169,9 +1160,6 @@ static void sign_define_cmd(char_u *sign_name, char_u *cmdline)
   char_u *culhl = NULL;
   char_u *numhl = NULL;
   int failed = false;
-  sign_T *sp_prev;
-
-  bool exists = sign_find(sign_name, &sp_prev) != NULL;
 
   // set values for a defined sign.
   for (;;) {
@@ -1188,31 +1176,15 @@ static void sign_define_cmd(char_u *sign_name, char_u *cmdline)
       text = vim_strnsave(arg, (size_t)(p - arg));
     } else if (STRNCMP(arg, "linehl=", 7) == 0) {
       arg += 7;
-      if (!exists && check_empty_group(p - arg, "linehl") == FAIL) {
-        failed = true;
-        break;
-      }
       linehl = vim_strnsave(arg, (size_t)(p - arg));
     } else if (STRNCMP(arg, "texthl=", 7) == 0) {
       arg += 7;
-      if (!exists && check_empty_group(p - arg, "texthl") == FAIL) {
-        failed = true;
-        break;
-      }
       texthl = vim_strnsave(arg, (size_t)(p - arg));
     } else if (STRNCMP(arg, "culhl=", 6) == 0) {
       arg += 6;
-      if (!exists && check_empty_group(p - arg, "culhl") == FAIL) {
-        failed = true;
-        break;
-      }
       culhl = vim_strnsave(arg, (size_t)(p - arg));
     } else if (STRNCMP(arg, "numhl=", 6) == 0) {
       arg += 6;
-      if (!exists && check_empty_group(p - arg, "numhl") == FAIL) {
-        failed = true;
-        break;
-      }
       numhl = vim_strnsave(arg, (size_t)(p - arg));
     } else {
       semsg(_(e_invarg2), arg);
diff --git a/src/nvim/testdir/test_signs.vim b/src/nvim/testdir/test_signs.vim
index c570d2c37e..799e6cb57b 100644
--- a/src/nvim/testdir/test_signs.vim
+++ b/src/nvim/testdir/test_signs.vim
@@ -126,11 +126,6 @@ func Test_sign()
   " call assert_fails("sign define Sign4 text= linehl=Comment", 'E239:')
   call assert_fails("sign define Sign4 text=\\ ab  linehl=Comment", 'E239:')
 
-  " an empty highlight argument for a new sign is an error
-  call assert_fails("sign define SignX linehl=", 'E1249: Group name missing for linehl')
-  call assert_fails("sign define SignX culhl=", 'E1249: Group name missing for culhl')
-  call assert_fails("sign define SignX texthl=", 'E1249: Group name missing for texthl')
-
   " an empty highlight argument for an existing sign clears it
   sign define SignY texthl=TextHl culhl=CulHl linehl=LineHl
   let sl = sign_getdefined('SignY')[0]