vim-patch:9.1.1340: cannot complete :filetype arguments (#33602)

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

fixes: vim/vim#17165
closes: vim/vim#17167

a3422aa317

Co-authored-by: Christian Brabandt <cb@256bit.org>

runtime/doc/builtin.txt

@@ -3401,6 +3401,7 @@ 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/lua/vim/_meta/vimfn.lua

@@ -3048,6 +3048,7 @@ function vim.fn.getcmdwintype() end
 --- 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

src/nvim/cmdexpand.c

@@ -110,6 +110,7 @@ static bool cmdline_fuzzy_completion_supported(const expand_T *const 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
@@ -1764,6 +1765,19 @@ static const char *set_context_in_lang_cmd(expand_T *xp, const char *arg)
   return NULL;
 }
 
+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;
+
+enum {
+  EXPAND_FILETYPECMD_PLUGIN = 0x01,
+  EXPAND_FILETYPECMD_INDENT = 0x02,
+  EXPAND_FILETYPECMD_ONOFF  = 0x04,
+};
+
 static enum {
   EXP_BREAKPT_ADD,  ///< expand ":breakadd" sub-commands
   EXP_BREAKPT_DEL,  ///< expand ":breakdel" sub-commands
@@ -1836,6 +1850,47 @@ static const char *set_context_in_scriptnames_cmd(expand_T *xp, const char *arg)
   return NULL;
 }
 
+/// Set the completion context for the :filetype command. Always returns NULL.
+static const char *set_context_in_filetype_cmd(expand_T *xp, const char *arg)
+{
+  xp->xp_context = EXPAND_FILETYPECMD;
+  xp->xp_pattern = (char *)arg;
+  filetype_expand_what = EXP_FILETYPECMD_ALL;
+
+  char *p = skipwhite(arg);
+  if (*p == NUL) {
+    return NULL;
+  }
+
+  int val = 0;
+
+  while (true) {
+    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".
 /// For user-defined commands and for environment variables, "context" has the
@@ -2198,6 +2253,9 @@ static const char *set_context_by_cmdname(const char *cmd, cmdidx_T cmdidx, expa
   case CMD_scriptnames:
     return set_context_in_scriptnames_cmd(xp, arg);
 
+  case CMD_filetype:
+    return set_context_in_filetype_cmd(xp, arg);
+
   case CMD_lua:
   case CMD_equal:
     xp->xp_context = EXPAND_LUA;
@@ -2565,6 +2623,30 @@ static int expand_files_and_dirs(expand_T *xp, char *pat, char ***matches, int *
   return ret;
 }
 
+/// Function given to ExpandGeneric() to obtain the possible arguments of the
+/// ":filetype {plugin,indent}" command.
+static char *get_filetypecmd_arg(expand_T *xp FUNC_ATTR_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 opts_all[idx];
+  }
+  if (filetype_expand_what == EXP_FILETYPECMD_PLUGIN && idx < 3) {
+    return opts_plugin[idx];
+  }
+  if (filetype_expand_what == EXP_FILETYPECMD_INDENT && idx < 3) {
+    return opts_indent[idx];
+  }
+  if (filetype_expand_what == EXP_FILETYPECMD_ONOFF && idx < 2) {
+    return opts_onoff[idx];
+  }
+  return NULL;
+}
+
 /// Function given to ExpandGeneric() to obtain the possible arguments of the
 /// ":breakadd {expr, file, func, here}" command.
 /// ":breakdel {func, file, here}" command.
@@ -2660,6 +2742,7 @@ static int ExpandOther(char *pat, expand_T *xp, regmatch_T *rmp, char ***matches
     int escaped;
   } tab[] = {
     { EXPAND_COMMANDS, get_command_name, false, 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 },
@@ -3643,6 +3726,9 @@ void f_getcompletion(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
     set_context_for_wildcard_arg(NULL, xpc.xp_pattern, false, &xpc, &context);
     xpc.xp_pattern_len = strlen(xpc.xp_pattern);
   }
+  if (xpc.xp_context == EXPAND_FILETYPECMD) {
+    filetype_expand_what = EXP_FILETYPECMD_ALL;
+  }
 
 theend:
   if (xpc.xp_context == EXPAND_LUA) {

src/nvim/cmdexpand_defs.h

@@ -108,6 +108,7 @@ enum {
   EXPAND_DIRS_IN_CDPATH,
   EXPAND_SHELLCMDLINE,
   EXPAND_FINDFUNC,
+  EXPAND_FILETYPECMD,
   EXPAND_CHECKHEALTH,
   EXPAND_LUA,
 };

src/nvim/eval.lua

@@ -3831,6 +3831,7 @@ M.funcs = {
       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

src/nvim/usercmd.c

@@ -72,6 +72,7 @@ static const char *command_complete[] = {
   [EXPAND_FILES] = "file",
   [EXPAND_FILES_IN_PATH] = "file_in_path",
   [EXPAND_FILETYPE] = "filetype",
+  [EXPAND_FILETYPECMD] = "filetypecmd",
   [EXPAND_FUNCTIONS] = "function",
   [EXPAND_HELP] = "help",
   [EXPAND_HIGHLIGHT] = "highlight",

test/old/testdir/test_cmdline.vim

@@ -548,6 +548,13 @@ 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')
@@ -3240,6 +3247,26 @@ 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