vim-patch:9.1.1509: patch 9.1.1505 was not good

Problem:  Patch 9.1.1505 was not good
Solution: Revert "patch 9.1.1505: not possible to return completion type
          for :ex command" and instead add the getcompletiontype()
          function (Hirohito Higashi).

related: vim/vim#17606
closes: vim/vim#17662

96b3ef2389

Cherry-pick Test_multibyte_expression() from Vim, as it passes.

Co-authored-by: Hirohito Higashi <h.east.727@gmail.com>
Co-authored-by: Shougo Matsushita <Shougo.Matsu@gmail.com>

src/nvim/cmdexpand.c

@@ -3838,6 +3838,30 @@ theend:
   ExpandCleanup(&xpc);
 }
 
+/// "getcompletiontype()" function
+void f_getcompletiontype(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
+{
+  rettv->v_type = VAR_STRING;
+  rettv->vval.v_string = NULL;
+
+  if (tv_check_for_string_arg(argvars, 0) == FAIL) {
+    return;
+  }
+
+  const char *pat = tv_get_string(&argvars[0]);
+  expand_T xpc;
+  ExpandInit(&xpc);
+
+  int cmdline_len = (int)strlen(pat);
+  set_cmd_context(&xpc, (char *)pat, cmdline_len, cmdline_len, false);
+  xpc.xp_pattern_len = strlen(xpc.xp_pattern);
+  xpc.xp_col = cmdline_len;
+
+  rettv->vval.v_string = get_cmdline_completion(&xpc);
+
+  ExpandCleanup(&xpc);
+}
+
 /// "cmdcomplete_info()" function
 void f_cmdcomplete_info(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 {

src/nvim/eval.lua

@@ -3751,22 +3751,22 @@ M.funcs = {
     signature = 'getcmdcomplpat()',
   },
   getcmdcompltype = {
-    args = { 0, 1 },
-    base = 1,
     desc = [=[
-      Return the type of command-line completion using {pat}.
-      If {pat} is omited, only works when the command line is being
-      edited, thus requires use of |c_CTRL-\_e| or |c_CTRL-R_=|.
-
+      Return the type of the current command-line completion.
+      Only works when the command line is being edited, thus
+      requires use of |c_CTRL-\_e| or |c_CTRL-R_=|.
       See |:command-completion| for the return string.
       Also see |getcmdtype()|, |setcmdpos()|, |getcmdline()|,
       |getcmdprompt()|, |getcmdcomplpat()| and |setcmdline()|.
       Returns an empty string when completion is not defined.
+
+      To get the type of the command-line completion for the
+      specified string, use |getcompletiontype()|.
     ]=],
     name = 'getcmdcompltype',
-    params = { { 'pat', 'string' } },
+    params = {},
     returns = 'string',
-    signature = 'getcmdcompltype([{pat}])',
+    signature = 'getcmdcompltype()',
   },
   getcmdline = {
     desc = [=[
@@ -3943,6 +3943,21 @@ M.funcs = {
     returns = 'string[]',
     signature = 'getcompletion({pat}, {type} [, {filtered}])',
   },
+  getcompletiontype = {
+    args = 1,
+    base = 1,
+    desc = [=[
+      Return the type of the command-line completion using {pat}.
+      When no corresponding completion type is found, an empty
+      string is returned.
+      To get the current command-line completion type, use
+      |getcmdcompltype()|.
+    ]=],
+    name = 'getcompletiontype',
+    params = { { 'pat', 'string' } },
+    returns = 'string',
+    signature = 'getcompletiontype({pat})',
+  },
   getcurpos = {
     args = { 0, 1 },
     base = 1,

src/nvim/ex_getln.c

@@ -4197,8 +4197,8 @@ static char *get_cmdline_completion_pattern(void)
   return xstrdup(compl_pat);
 }
 
-/// Get the current command-line completion type.
-static char *get_cmdline_completion(expand_T *xpc)
+/// Get the command-line completion type.
+char *get_cmdline_completion(expand_T *xpc)
 {
   int xp_context = xpc->xp_context;
   if (xp_context == EXPAND_NOTHING) {
@@ -4235,34 +4235,15 @@ void f_getcmdcomplpat(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 /// "getcmdcompltype()" function
 void f_getcmdcompltype(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 {
-  if (tv_check_for_opt_string_arg(argvars, 0) == FAIL) {
+  rettv->v_type = VAR_STRING;
+  rettv->vval.v_string = NULL;
+
+  CmdlineInfo *p = get_ccline_ptr();
+  if (cmdline_star > 0 || p == NULL || p->xpc == NULL) {
     return;
   }
 
-  rettv->v_type = VAR_STRING;
-
-  if (argvars[0].v_type != VAR_UNKNOWN) {
-    char *pat = (char *)tv_get_string(&argvars[0]);
-    expand_T xpc;
-    ExpandInit(&xpc);
-
-    int cmdline_len = (int)strlen(pat);
-    set_cmd_context(&xpc, pat, cmdline_len, cmdline_len, false);
-    xpc.xp_pattern_len = strlen(xpc.xp_pattern);
-    xpc.xp_col = cmdline_len;
-
-    rettv->v_type = VAR_STRING;
-    rettv->vval.v_string = get_cmdline_completion(&xpc);
-
-    ExpandCleanup(&xpc);
-  } else {
-    CmdlineInfo *p = get_ccline_ptr();
-    if (cmdline_star > 0 || p == NULL || p->xpc == NULL) {
-      return;
-    }
-
-    rettv->vval.v_string = get_cmdline_completion(p->xpc);
-  }
+  rettv->vval.v_string = get_cmdline_completion(p->xpc);
 }
 
 /// "getcmdline()" function