patch 9.0.1227: no cmdline completion for :runtime

Problem:    No cmdline completion for :runtime.
Solution:   Add completion for :runtime. (closes #11853, closes #11447)
            Improve the resulting matches.

src/cmdexpand.c

@@ -56,6 +56,7 @@ cmdline_fuzzy_completion_supported(expand_T *xp)
 	    && xp->xp_context != EXPAND_OLD_SETTING
 	    && xp->xp_context != EXPAND_OWNSYNTAX
 	    && xp->xp_context != EXPAND_PACKADD
+	    && xp->xp_context != EXPAND_RUNTIME
 	    && xp->xp_context != EXPAND_SHELLCMD
 	    && xp->xp_context != EXPAND_TAGS
 	    && xp->xp_context != EXPAND_TAGS_LISTFILES
@@ -1362,6 +1363,7 @@ addstar(
 	// For a tag pattern starting with "/" no translation is needed.
 	if (context == EXPAND_HELP
 		|| context == EXPAND_COLORS
+		|| context == EXPAND_RUNTIME
 		|| context == EXPAND_COMPILER
 		|| context == EXPAND_OWNSYNTAX
 		|| context == EXPAND_FILETYPE
@@ -2312,6 +2314,11 @@ set_context_by_cmdname(
 	    xp->xp_pattern = arg;
 	    break;
 
+	case CMD_runtime:
+	    xp->xp_context = EXPAND_RUNTIME;
+	    xp->xp_pattern = arg;
+	    break;
+
 	case CMD_compiler:
 	    xp->xp_context = EXPAND_COMPILER;
 	    xp->xp_pattern = arg;
@@ -3019,6 +3026,12 @@ ExpandFromContext(
 	return ExpandRTDir(pat, DIP_START + DIP_OPT, numMatches, matches,
 								directories);
     }
+    if (xp->xp_context == EXPAND_RUNTIME)
+    {
+	char *directories[] = {"", NULL};
+	return ExpandRTDir(pat, DIP_START + DIP_OPT + DIP_PRNEXT, numMatches,
+							 matches, directories);
+    }
     if (xp->xp_context == EXPAND_COMPILER)
     {
 	char *directories[] = {"compiler", NULL};

src/scriptfile.c

@@ -990,18 +990,34 @@ ExpandRTDir(
 
     for (i = 0; dirnames[i] != NULL; ++i)
     {
-	s = alloc(STRLEN(dirnames[i]) + pat_len + 7);
-	if (s == NULL)
+	size_t buflen = STRLEN(dirnames[i]) + pat_len * 2 + 17;
+	char_u *buf = alloc(buflen);
+	if (buf == NULL)
 	{
 	    ga_clear_strings(&ga);
 	    return FAIL;
 	}
-	sprintf((char *)s, "%s/%s*.vim", dirnames[i], pat);
-	globpath(p_rtp, s, &ga, 0);
-	vim_free(s);
+	if (*(dirnames[i]) == NUL)
+	{
+	    // empty dir used for :runtime
+	    if (gettail(pat) == pat)
+		// no path separator, match dir names and script files
+		vim_snprintf((char *)buf, buflen, "\\(%s*.vim\\)\\|\\(%s*\\)",
+								     pat, pat);
+	    else
+		// has path separator, match script files
+		vim_snprintf((char *)buf, buflen, "%s*.vim", pat);
+	}
+	else
+	{
+	    vim_snprintf((char *)buf, buflen, "%s/%s*.vim", dirnames[i], pat);
+	}
+	globpath(p_rtp, buf, &ga, 0);
+	vim_free(buf);
     }
 
-    if (flags & DIP_START) {
+    if (flags & DIP_START)
+    {
 	for (i = 0; dirnames[i] != NULL; ++i)
 	{
 	    s = alloc(STRLEN(dirnames[i]) + pat_len + 22);
@@ -1016,7 +1032,8 @@ ExpandRTDir(
 	}
     }
 
-    if (flags & DIP_OPT) {
+    if (flags & DIP_OPT)
+    {
 	for (i = 0; dirnames[i] != NULL; ++i)
 	{
 	    s = alloc(STRLEN(dirnames[i]) + pat_len + 20);
@@ -1036,15 +1053,52 @@ ExpandRTDir(
 	match = ((char_u **)ga.ga_data)[i];
 	s = match;
 	e = s + STRLEN(s);
+	char_u *res_start = s;
+	if ((flags & DIP_PRNEXT) != 0)
+	{
+	    char_u *p = (char_u *)strstr((char *)match, (char *)pat);
+	    if (p != NULL)
+		// Drop what comes before "pat" in the match, so that for
+		// match "/long/path/syntax/cpp.vim" with pattern
+		// "syntax/cp" we only keep "syntax/cpp.vim".
+		res_start = p;
+	}
+
 	if (e - 4 > s && STRNICMP(e - 4, ".vim", 4) == 0)
 	{
-	    e -= 4;
-	    for (s = e; s > match; MB_PTR_BACK(match, s))
-		if (s < match || vim_ispathsep(*s))
-		    break;
-	    ++s;
+	    if (res_start == s)
+	    {
+		// Only keep the file name.
+		// Remove file ext only if flag DIP_PRNEXT is not present.
+		if ((flags & DIP_PRNEXT) == 0)
+		    e -= 4;
+		for (s = e; s > match; MB_PTR_BACK(match, s))
+		{
+		    if (s < match)
+			break;
+		    if (vim_ispathsep(*s))
+		    {
+			res_start = s + 1;
+			break;
+		    }
+		}
+	    }
+
 	    *e = NUL;
-	    mch_memmove(match, s, e - s + 1);
+	}
+
+	if (res_start > match)
+	    mch_memmove(match, res_start, e - res_start + 1);
+
+	// remove entries that look like backup files
+	if (e > s && e[-1] == '~')
+	{
+	    vim_free(match);
+	    char_u  **fnames = (char_u **)ga.ga_data;
+	    for (int j = i + 1; j < ga.ga_len; ++j)
+		fnames[j - 1] = fnames[j];
+	    --ga.ga_len;
+	    --i;
 	}
     }
 

src/testdir/test_cmdline.vim

@@ -552,6 +552,15 @@ func Test_getcompletion()
   call assert_true(index(l, '<buffer>') >= 0)
   let l = getcompletion('not', 'mapclear')
   call assert_equal([], l)
+  
+  let l = getcompletion('', 'runtime')
+  call assert_true(index(l, 'defaults.vim') >= 0)
+  let l = getcompletion('synt', 'runtime')
+  call assert_true(index(l, 'syntax') >= 0)
+  let l = getcompletion('syntax/vi', 'runtime')
+  call assert_true(index(l, 'syntax/vim.vim') >= 0)
+  let l = getcompletion('notexitsts', 'runtime')
+  call assert_equal([], l)
 
   let l = getcompletion('.', 'shellcmd')
   call assert_equal(['./', '../'], filter(l, 'v:val =~ "\\./"'))

src/usercmd.c

@@ -86,6 +86,7 @@ static struct
 #endif
     {EXPAND_SETTINGS, "option"},
     {EXPAND_PACKADD, "packadd"},
+    {EXPAND_RUNTIME, "runtime"},
     {EXPAND_SHELLCMD, "shellcmd"},
 #if defined(FEAT_SIGNS)
     {EXPAND_SIGN, "sign"},

src/version.c

@@ -695,6 +695,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1227,
 /**/
     1226,
 /**/

src/vim.h

@@ -811,6 +811,7 @@ extern int (*dyn_libintl_wputenv)(const wchar_t *envstring);
 #define EXPAND_DISASSEMBLE	50
 #define EXPAND_BREAKPOINT	51
 #define EXPAND_SCRIPTNAMES	52
+#define EXPAND_RUNTIME		53
 
 // Values for exmode_active (0 is no exmode)
 #define EXMODE_NORMAL		1
@@ -2661,6 +2662,7 @@ typedef enum {
 #define DIP_NORTP   0x20	// do not use 'runtimepath'
 #define DIP_NOAFTER 0x40	// skip "after" directories
 #define DIP_AFTER   0x80	// only use "after" directories
+#define DIP_PRNEXT  0x100	// for print also file extension
 
 // Lowest number used for window ID. Cannot have this many windows.
 #define LOWEST_WIN_ID 1000