patch 8.1.2293: join adds trailing space when second line is empty

Problem:    Join adds trailing space when second line is empty. (Brennan
            Vincent)
Solution:   Do not add a trailing space.

src/ops.c

@@ -1999,7 +1999,8 @@ do_join(
 	if (insert_space && t > 0)
 	{
 	    curr = skipwhite(curr);
-	    if (*curr != ')' && currsize != 0 && endcurr1 != TAB
+	    if (*curr != NUL && *curr != ')'
+		    && currsize != 0 && endcurr1 != TAB
 		    && (!has_format_option(FO_MBYTE_JOIN)
 			|| (mb_ptr2char(curr) < 0x100 && endcurr1 < 0x100))
 		    && (!has_format_option(FO_MBYTE_JOIN2)

src/testdir/test_join.vim

@@ -9,6 +9,27 @@ func Test_join_with_count()
   call setline(1, ['one', 'two', 'three', 'four'])
   normal 10J
   call assert_equal('one two three four', getline(1))
+
+  call setline(1, ['one', '', 'two'])
+  normal J
+  call assert_equal('one', getline(1))
+
+  call setline(1, ['one', ' ', 'two'])
+  normal J
+  call assert_equal('one', getline(1))
+
+  call setline(1, ['one', '', '', 'two'])
+  normal JJ
+  call assert_equal('one', getline(1))
+
+  call setline(1, ['one', ' ', ' ', 'two'])
+  normal JJ
+  call assert_equal('one', getline(1))
+
+  call setline(1, ['one', '', '', 'two'])
+  normal 2J
+  call assert_equal('one', getline(1))
+
   quit!
 endfunc
 

src/version.c

@@ -741,6 +741,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    2293,
 /**/
     2292,
 /**/