patch 9.1.1340: cannot complete :filetype arguments

Problem:  cannot complete :filetype arguments (Phạm Bình An)
Solution: add :filetype ex command completion, add "filetypecmd"
          completion type for getcompletion()

fixes: #17165
closes: #17167

Co-authored-by: zeertzjq <zeertzjq@outlook.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>

runtime/doc/builtin.txt

@@ -4270,6 +4270,7 @@ getcompletion({pat}, {type} [, {filtered}])		*getcompletion()*
 		file		file and directory names
 		file_in_path	file and directory names in |'path'|
 		filetype	filetype names |'filetype'|
+		filetypecmd	|:filetype| suboptions
 		function	function name
 		help		help subjects
 		highlight	highlight groups

runtime/doc/version9.txt

@@ -1,4 +1,4 @@
-*version9.txt*  For Vim version 9.1.  Last change: 2025 Apr 21
+*version9.txt*  For Vim version 9.1.  Last change: 2025 Apr 23
 
 
 		  VIM REFERENCE MANUAL    by Bram Moolenaar
@@ -41624,6 +41624,8 @@ Completion: ~
 	"o"		- complete using 'omnifunc'
 - allow to limit matches for the 'complete' sources by using the
   "{flag}^<limit>" notation
+- add ":filetype" command completion
+- add "filetypecmd" completion type for |getcompletion()|
 
 Options: ~
 - the default for 'commentstring' contains whitespace padding to have

src/cmdexpand.c

@@ -53,6 +53,7 @@ cmdline_fuzzy_completion_supported(expand_T *xp)
 	    && xp->xp_context != EXPAND_FILES
 	    && xp->xp_context != EXPAND_FILES_IN_PATH
 	    && xp->xp_context != EXPAND_FILETYPE
+	    && xp->xp_context != EXPAND_FILETYPECMD
 	    && xp->xp_context != EXPAND_FINDFUNC
 	    && xp->xp_context != EXPAND_HELP
 	    && xp->xp_context != EXPAND_KEYMAP
@@ -2058,6 +2059,18 @@ set_context_in_lang_cmd(expand_T *xp, char_u *arg)
 }
 #endif
 
+static enum
+{
+    EXP_FILETYPECMD_ALL,	// expand all :filetype values
+    EXP_FILETYPECMD_PLUGIN,	// expand plugin on off
+    EXP_FILETYPECMD_INDENT,	// expand indent on off
+    EXP_FILETYPECMD_ONOFF,	// expand on off
+} filetype_expand_what;
+
+#define EXPAND_FILETYPECMD_PLUGIN 0x01
+#define EXPAND_FILETYPECMD_INDENT 0x02
+#define EXPAND_FILETYPECMD_ONOFF  0x04
+
 #ifdef FEAT_EVAL
 static enum
 {
@@ -2143,6 +2156,53 @@ set_context_in_scriptnames_cmd(expand_T *xp, char_u *arg)
 }
 #endif
 
+/*
+ * Set the completion context for the :filetype command. Always returns NULL.
+ */
+    static char_u *
+set_context_in_filetype_cmd(expand_T *xp, char_u *arg)
+{
+    char_u *p;
+    int    val = 0;
+
+    xp->xp_context = EXPAND_FILETYPECMD;
+    xp->xp_pattern = arg;
+    filetype_expand_what = EXP_FILETYPECMD_ALL;
+
+    p = skipwhite(arg);
+    if (*p == NUL)
+	return NULL;
+
+    for (;;)
+    {
+	if (STRNCMP(p, "plugin", 6) == 0)
+	{
+	    val |= EXPAND_FILETYPECMD_PLUGIN;
+	    p = skipwhite(p + 6);
+	    continue;
+	}
+	if (STRNCMP(p, "indent", 6) == 0)
+	{
+	    val |= EXPAND_FILETYPECMD_INDENT;
+	    p = skipwhite(p + 6);
+	    continue;
+	}
+	break;
+    }
+
+    if ((val & EXPAND_FILETYPECMD_PLUGIN) && (val & EXPAND_FILETYPECMD_INDENT))
+	filetype_expand_what = EXP_FILETYPECMD_ONOFF;
+    else if ((val & EXPAND_FILETYPECMD_PLUGIN))
+	filetype_expand_what = EXP_FILETYPECMD_INDENT;
+    else if ((val & EXPAND_FILETYPECMD_INDENT))
+	filetype_expand_what = EXP_FILETYPECMD_PLUGIN;
+
+    xp->xp_pattern = p;
+
+    return NULL;
+}
+
+
 /*
  * Set the completion context in 'xp' for command 'cmd' with index 'cmdidx'.
  * The argument to the command is 'arg' and the argument flags is 'argt'.
@@ -2515,6 +2575,8 @@ set_context_by_cmdname(
 	case CMD_scriptnames:
 	    return set_context_in_scriptnames_cmd(xp, arg);
 #endif
+	case CMD_filetype:
+	    return set_context_in_filetype_cmd(xp, arg);
 
 	default:
 	    break;
@@ -2949,6 +3011,29 @@ get_behave_arg(expand_T *xp UNUSED, int idx)
     return NULL;
 }
 
+/*
+ * Function given to ExpandGeneric() to obtain the possible arguments of the
+ * ":filetype {plugin,indent}" command.
+ */
+    static char_u *
+get_filetypecmd_arg(expand_T *xp UNUSED, int idx)
+{
+    char *opts_all[] = {"indent", "plugin", "on", "off"};
+    char *opts_plugin[] = {"plugin", "on", "off"};
+    char *opts_indent[] = {"indent", "on", "off"};
+    char *opts_onoff[] = {"on", "off"};
+
+    if (filetype_expand_what == EXP_FILETYPECMD_ALL && idx < 4)
+	return (char_u *)opts_all[idx];
+    if (filetype_expand_what == EXP_FILETYPECMD_PLUGIN && idx < 3)
+	return (char_u *)opts_plugin[idx];
+    if (filetype_expand_what == EXP_FILETYPECMD_INDENT && idx < 3)
+	return (char_u *)opts_indent[idx];
+    if (filetype_expand_what == EXP_FILETYPECMD_ONOFF && idx < 2)
+	return (char_u *)opts_onoff[idx];
+    return NULL;
+}
+
 #ifdef FEAT_EVAL
 /*
  * Function given to ExpandGeneric() to obtain the possible arguments of the
@@ -3040,6 +3125,7 @@ ExpandOther(
     {
 	{EXPAND_COMMANDS, get_command_name, FALSE, TRUE},
 	{EXPAND_BEHAVE, get_behave_arg, TRUE, TRUE},
+	{EXPAND_FILETYPECMD, get_filetypecmd_arg, TRUE, TRUE},
 	{EXPAND_MAPCLEAR, get_mapclear_arg, TRUE, TRUE},
 	{EXPAND_MESSAGES, get_messages_arg, TRUE, TRUE},
 	{EXPAND_HISTORY, get_history_arg, TRUE, TRUE},
@@ -4295,6 +4381,8 @@ f_getcompletion(typval_T *argvars, typval_T *rettv)
 								     &context);
 	    xpc.xp_pattern_len = (int)STRLEN(xpc.xp_pattern);
 	}
+	if (xpc.xp_context == EXPAND_FILETYPECMD)
+	    filetype_expand_what = EXP_FILETYPECMD_ALL;
     }
 
     if (cmdline_fuzzy_completion_supported(&xpc))

src/testdir/test_cmdline.vim

@@ -684,6 +684,13 @@ func Test_getcompletion()
   let l = getcompletion('kill', 'expression')
   call assert_equal([], l)
 
+  let l = getcompletion('', 'filetypecmd')
+  call assert_equal(["indent", "off", "on", "plugin"], l)
+  let l = getcompletion('not', 'filetypecmd')
+  call assert_equal([], l)
+  let l = getcompletion('o', 'filetypecmd')
+  call assert_equal(['off', 'on'], l)
+
   let l = getcompletion('tag', 'function')
   call assert_true(index(l, 'taglist(') >= 0)
   let l = getcompletion('paint', 'function')
@@ -3209,6 +3216,26 @@ func Test_fuzzy_completion_behave()
   set wildoptions&
 endfunc
 
+" :filetype suboptions completion
+func Test_completion_filetypecmd()
+  set wildoptions&
+  call feedkeys(":filetype \<C-A>\<C-B>\"\<CR>", 'tx')
+  call assert_equal('"filetype indent off on plugin', @:)
+  call feedkeys(":filetype plugin \<C-A>\<C-B>\"\<CR>", 'tx')
+  call assert_equal('"filetype plugin indent off on', @:)
+  call feedkeys(":filetype indent \<C-A>\<C-B>\"\<CR>", 'tx')
+  call assert_equal('"filetype indent off on plugin', @:)
+  call feedkeys(":filetype i\<C-A>\<C-B>\"\<CR>", 'tx')
+  call assert_equal('"filetype indent', @:)
+  call feedkeys(":filetype p\<C-A>\<C-B>\"\<CR>", 'tx')
+  call assert_equal('"filetype plugin', @:)
+  call feedkeys(":filetype o\<C-A>\<C-B>\"\<CR>", 'tx')
+  call assert_equal('"filetype off on', @:)
+  call feedkeys(":filetype indent of\<C-A>\<C-B>\"\<CR>", 'tx')
+  call assert_equal('"filetype indent off', @:)
+  set wildoptions&
+endfunc
+
 " " colorscheme name fuzzy completion - NOT supported
 " func Test_fuzzy_completion_colorscheme()
 " endfunc

src/usercmd.c

@@ -71,6 +71,7 @@ static keyvalue_T command_complete_tab[] =
     KEYVALUE_ENTRY(EXPAND_FILES, "file"),
     KEYVALUE_ENTRY(EXPAND_FILES_IN_PATH, "file_in_path"),
     KEYVALUE_ENTRY(EXPAND_FILETYPE, "filetype"),
+    KEYVALUE_ENTRY(EXPAND_FILETYPECMD, "filetypecmd"),
     KEYVALUE_ENTRY(EXPAND_FUNCTIONS, "function"),
     KEYVALUE_ENTRY(EXPAND_HELP, "help"),
     KEYVALUE_ENTRY(EXPAND_HIGHLIGHT, "highlight"),

src/version.c

@@ -704,6 +704,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1340,
 /**/
     1339,
 /**/

src/vim.h

@@ -854,6 +854,7 @@ extern int (*dyn_libintl_wputenv)(const wchar_t *envstring);
 #define EXPAND_SHELLCMDLINE	60
 #define EXPAND_FINDFUNC		61
 #define EXPAND_HIGHLIGHT_GROUP  62
+#define EXPAND_FILETYPECMD	63
 
 
 // Values for exmode_active (0 is no exmode)