patch 8.1.0296: command parsing for 'incsearch' is a bit ugly

Problem:    Command parsing for 'incsearch' is a bit ugly.
Solution:   Return when there is no pattern.  Put common checks together.

src/ex_getln.c

@@ -276,26 +276,30 @@ set_search_match(pos_T *t)
 do_incsearch_highlighting(int firstc, incsearch_state_T *is_state,
 						     int *skiplen, int *patlen)
 {
+    char_u	*cmd;
+    cmdmod_T	save_cmdmod = cmdmod;
+    char_u	*p;
+    int		delim_optional = FALSE;
+    int		delim;
+    char_u	*end;
+    char_u	*dummy;
+    exarg_T	ea;
+    pos_T	save_cursor;
+
     *skiplen = 0;
     *patlen = ccline.cmdlen;
 
-    if (p_is && !cmd_silent)
+    if (!p_is || cmd_silent)
-    {
+	return FALSE;
+
     // by default search all lines
     search_first_line = 0;
     search_last_line = MAXLNUM;
 
     if (firstc == '/' || firstc == '?')
 	return TRUE;
-	if (firstc == ':')
+    if (firstc != ':')
-	{
+	return FALSE;
-	    char_u	*cmd;
-	    cmdmod_T	save_cmdmod = cmdmod;
-	    char_u	*p;
-	    int		delim;
-	    char_u	*end;
-	    char_u	*dummy;
-	    exarg_T	ea;
 
     vim_memset(&ea, 0, sizeof(ea));
     ea.line1 = 1;
@@ -307,77 +311,65 @@ do_incsearch_highlighting(int firstc, incsearch_state_T *is_state,
     cmdmod = save_cmdmod;
 
     cmd = skip_range(ea.cmd, NULL);
-	    if (*cmd == 's' || *cmd == 'g' || *cmd == 'v' || *cmd == 'l')
+    if (vim_strchr((char_u *)"sgvl", *cmd) == NULL)
-	    {
+	return FALSE;
+
     // Skip over "substitute" to find the pattern separator.
     for (p = cmd; ASCII_ISALPHA(*p); ++p)
 	;
-		if (*skipwhite(p) != NUL)
+    if (*skipwhite(p) == NUL)
-		{
+	return FALSE;
+
     if (STRNCMP(cmd, "substitute", p - cmd) == 0
 	    || STRNCMP(cmd, "smagic", p - cmd) == 0
 	    || STRNCMP(cmd, "snomagic", MAX(p - cmd, 3)) == 0
-			|| STRNCMP(cmd, "sort", MAX(p - cmd, 3)) == 0
-			|| STRNCMP(cmd, "global", p - cmd) == 0
 	    || STRNCMP(cmd, "vglobal", p - cmd) == 0)
     {
 	if (*cmd == 's' && cmd[1] == 'm')
 	    p_magic = TRUE;
 	else if (*cmd == 's' && cmd[1] == 'n')
 	    p_magic = FALSE;
-
-			// Check for "global!/".
-			if (*cmd == 'g' && *p == '!')
-			{
-			    p++;
-			    if (*skipwhite(p) == NUL)
-				return FALSE;
     }
-
+    else if (STRNCMP(cmd, "sort", MAX(p - cmd, 3)) == 0)
-			// For ":sort" skip over flags.
-			if (cmd[0] == 's' && cmd[1] == 'o')
     {
+	// skip over flags
 	while (ASCII_ISALPHA(*(p = skipwhite(p))))
 	    ++p;
 	if (*p == NUL)
 	    return FALSE;
     }
-
-			p = skipwhite(p);
-			delim = *p++;
-			end = skip_regexp(p, delim, p_magic, NULL);
-		    }
     else if (STRNCMP(cmd, "vimgrep", MAX(p - cmd, 3)) == 0
 	|| STRNCMP(cmd, "vimgrepadd", MAX(p - cmd, 8)) == 0
 	|| STRNCMP(cmd, "lvimgrep", MAX(p - cmd, 2)) == 0
-			|| STRNCMP(cmd, "lvimgrepadd", MAX(p - cmd, 9)) == 0)
+	|| STRNCMP(cmd, "lvimgrepadd", MAX(p - cmd, 9)) == 0
+	|| STRNCMP(cmd, "global", p - cmd) == 0)
     {
-			// Check for "!/".
+	// skip over "!"
 	if (*p == '!')
 	{
 	    p++;
 	    if (*skipwhite(p) == NUL)
 		return FALSE;
 	}
-			p = skipwhite(p);
+	if (*cmd != 'g')
-			delim = (vim_isIDc(*p)) ? ' ' : *p++;
+	    delim_optional = TRUE;
-			end = skip_regexp(p, delim, p_magic, NULL);
     }
     else
-		    {
+	return FALSE;
-			end = p;
-			delim = -1;
-		    }
 
-		    if (end > p || *end == delim)
+    p = skipwhite(p);
-		    {
+    delim = (delim_optional && vim_isIDc(*p)) ? ' ' : *p++;
-			pos_T	save_cursor = curwin->w_cursor;
+    end = skip_regexp(p, delim, p_magic, NULL);
 
+    if (end == p && *end != delim)
+	return FALSE;
     // found a non-empty pattern or //
+
     *skiplen = (int)(p - ccline.cmdbuff);
     *patlen = (int)(end - p);
 
     // parse the address range
+    save_cursor = curwin->w_cursor;
     curwin->w_cursor = is_state->search_start;
     parse_cmd_address(&ea, &dummy);
     if (ea.addr_count > 0)
@@ -404,13 +396,6 @@ do_incsearch_highlighting(int firstc, incsearch_state_T *is_state,
     curwin->w_cursor = save_cursor;
     return TRUE;
 }
-		}
-	    }
-	}
-    }
-
-    return FALSE;
-}
 
     static void
 finish_incsearch_highlighting(

src/version.c

@@ -794,6 +794,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    296,
 /**/
     295,
 /**/