patch 8.2.0925: getcompletion() does not return command line arguments

Problem:    Getcompletion() does not return command line arguments.
Solution:   Add the "cmdline" option. (Shougo, closes #1140)

runtime/doc/eval.txt

@@ -5112,6 +5112,7 @@ getcompletion({pat}, {type} [, {filtered}])		*getcompletion()*
 		behave		:behave suboptions
 		color		color schemes
 		command		Ex command (and arguments)
+		cmdline		|cmdline-completion| result
 		compiler	compilers
 		cscope		|:cscope| suboptions
 		diff_buffer     |:diffget| and |:diffput| completion
@@ -5142,14 +5143,19 @@ getcompletion({pat}, {type} [, {filtered}])		*getcompletion()*
 		user		user names
 		var		user variables
 
-		If {pat} is an empty string, then all the matches are returned.
+		If {pat} is an empty string, then all the matches are
-		Otherwise only items matching {pat} are returned. See
+		returned.  Otherwise only items matching {pat} are returned.
-		|wildcards| for the use of special characters in {pat}.
+		See |wildcards| for the use of special characters in {pat}.
 
 		If the optional {filtered} flag is set to 1, then 'wildignore'
 		is applied to filter the results.  Otherwise all the matches
 		are returned. The 'wildignorecase' option always applies.
 
+		If {type} is "cmdline", then the |cmdline-completion| result is
+		returned.  For example, to complete the possible values after
+		a ":call" command: >
+                	echo getcompletion('call ', 'cmdline')
+<
 		If there are no matches, an empty list is returned.  An
 		invalid value for {type} produces an error.
 

src/cmdexpand.c

@@ -2675,10 +2675,18 @@ globpath(
 f_getcompletion(typval_T *argvars, typval_T *rettv)
 {
     char_u	*pat;
+    char_u	*type;
     expand_T	xpc;
     int		filtered = FALSE;
     int		options = WILD_SILENT | WILD_USE_NL | WILD_ADD_SLASH
-					| WILD_NO_BEEP;
+								| WILD_NO_BEEP;
+
+    if (argvars[1].v_type != VAR_STRING)
+    {
+	semsg(_(e_invarg2), "type must be a string");
+	return;
+    }
+    type = tv_get_string(&argvars[1]);
 
     if (argvars[2].v_type != VAR_UNKNOWN)
 	filtered = tv_get_number_chk(&argvars[2], NULL);
@@ -2691,39 +2699,45 @@ f_getcompletion(typval_T *argvars, typval_T *rettv)
 	options |= WILD_KEEP_ALL;
 
     ExpandInit(&xpc);
-    xpc.xp_pattern = tv_get_string(&argvars[0]);
+    if (STRCMP(type, "cmdline") == 0)
-    xpc.xp_pattern_len = (int)STRLEN(xpc.xp_pattern);
-    xpc.xp_context = cmdcomplete_str_to_type(tv_get_string(&argvars[1]));
-    if (xpc.xp_context == EXPAND_NOTHING)
     {
-	if (argvars[1].v_type == VAR_STRING)
+	set_one_cmd_context(&xpc, tv_get_string(&argvars[0]));
-	    semsg(_(e_invarg2), argvars[1].vval.v_string);
+	xpc.xp_pattern_len = (int)STRLEN(xpc.xp_pattern);
-	else
-	    emsg(_(e_invarg));
-	return;
     }
+    else
+    {
+	xpc.xp_pattern = tv_get_string(&argvars[0]);
+	xpc.xp_pattern_len = (int)STRLEN(xpc.xp_pattern);
+
+	xpc.xp_context = cmdcomplete_str_to_type(type);
+	if (xpc.xp_context == EXPAND_NOTHING)
+	{
+	    semsg(_(e_invarg2), type);
+	    return;
+	}
 
 # if defined(FEAT_MENU)
-    if (xpc.xp_context == EXPAND_MENUS)
+	if (xpc.xp_context == EXPAND_MENUS)
-    {
+	{
-	set_context_in_menu_cmd(&xpc, (char_u *)"menu", xpc.xp_pattern, FALSE);
+	    set_context_in_menu_cmd(&xpc, (char_u *)"menu", xpc.xp_pattern, FALSE);
-	xpc.xp_pattern_len = (int)STRLEN(xpc.xp_pattern);
+	    xpc.xp_pattern_len = (int)STRLEN(xpc.xp_pattern);
-    }
+	}
 # endif
 # ifdef FEAT_CSCOPE
-    if (xpc.xp_context == EXPAND_CSCOPE)
+	if (xpc.xp_context == EXPAND_CSCOPE)
-    {
+	{
-	set_context_in_cscope_cmd(&xpc, xpc.xp_pattern, CMD_cscope);
+	    set_context_in_cscope_cmd(&xpc, xpc.xp_pattern, CMD_cscope);
-	xpc.xp_pattern_len = (int)STRLEN(xpc.xp_pattern);
+	    xpc.xp_pattern_len = (int)STRLEN(xpc.xp_pattern);
-    }
+	}
 # endif
 # ifdef FEAT_SIGNS
-    if (xpc.xp_context == EXPAND_SIGN)
+	if (xpc.xp_context == EXPAND_SIGN)
-    {
+	{
-	set_context_in_sign_cmd(&xpc, xpc.xp_pattern);
+	    set_context_in_sign_cmd(&xpc, xpc.xp_pattern);
-	xpc.xp_pattern_len = (int)STRLEN(xpc.xp_pattern);
+	    xpc.xp_pattern_len = (int)STRLEN(xpc.xp_pattern);
-    }
+	}
 # endif
+    }
 
     pat = addstar(xpc.xp_pattern, xpc.xp_pattern_len, xpc.xp_context);
     if ((rettv_list_alloc(rettv) != FAIL) && (pat != NULL))

src/testdir/test_cmdline.vim

@@ -355,6 +355,20 @@ func Test_getcompletion()
     call assert_equal(['Testing'], l)
   endif
 
+  " Command line completion tests
+  let l = getcompletion('cd ', 'cmdline')
+  call assert_true(index(l, 'samples/') >= 0)
+  let l = getcompletion('cd NoMatch', 'cmdline')
+  call assert_equal([], l)
+  let l = getcompletion('let v:n', 'cmdline')
+  call assert_true(index(l, 'v:null') >= 0)
+  let l = getcompletion('let v:notexists', 'cmdline')
+  call assert_equal([], l)
+  let l = getcompletion('call tag', 'cmdline')
+  call assert_true(index(l, 'taglist(') >= 0)
+  let l = getcompletion('call paint', 'cmdline')
+  call assert_equal([], l)
+
   " For others test if the name is recognized.
   let names = ['buffer', 'environment', 'file_in_path', 'mapping', 'tag', 'tag_listfiles', 'user']
   if has('cmdline_hist')
@@ -379,7 +393,7 @@ func Test_getcompletion()
   set tags&
 
   call assert_fails('call getcompletion("", "burp")', 'E475:')
-  call assert_fails('call getcompletion("abc", [])', 'E474:')
+  call assert_fails('call getcompletion("abc", [])', 'E475:')
 endfunc
 
 func Test_shellcmd_completion()

src/version.c

@@ -754,6 +754,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    925,
 /**/
     924,
 /**/