patch 9.1.0565: Stop directory doesn't work properly in 'tags'

Problem:  Stop directory doesn't work properly in 'tags'.
          (Jesse Pavel)
Solution: Also move the stop directory forward by one byte.
          (zeertzjq)

This doesn't support relative stop directories yet, as they are not
supported in other places like findfile() either.

fixes: #15200
related: #15202

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

src/tag.c

@@ -3412,6 +3412,11 @@ get_tagfname(
 	    // move the filename one char forward and truncate the
 	    // filepath with a NUL
 	    filename = gettail(buf);
+	    if (r_ptr != NULL)
+	    {
+		STRMOVE(r_ptr + 1, r_ptr);
+		++r_ptr;
+	    }
 	    STRMOVE(filename + 1, filename);
 	    *filename++ = NUL;
 

src/testdir/test_taglist.vim

@@ -127,6 +127,29 @@ func Test_tagsfile_without_trailing_newline()
   set tags&
 endfunc
 
+" Check that specifying a stop directory in 'tags' works properly.
+func Test_tagfiles_stopdir()
+  let save_cwd = getcwd()
+
+  call mkdir('Xtagsdir1/Xtagsdir2/Xtagsdir3', 'pR')
+  call writefile([], 'Xtagsdir1/Xtags', 'D')
+
+  cd Xtagsdir1/
+  let &tags = './Xtags;' .. fnamemodify('./..', ':p')
+  call assert_equal(1, len(tagfiles()))
+
+  cd Xtagsdir2/
+  let &tags = './Xtags;' .. fnamemodify('./..', ':p')
+  call assert_equal(1, len(tagfiles()))
+
+  cd Xtagsdir3/
+  let &tags = './Xtags;' .. fnamemodify('./..', ':p')
+  call assert_equal(0, len(tagfiles()))
+
+  set tags&
+  call chdir(save_cwd)
+endfunc
+
 " Test for ignoring comments in a tags file
 func Test_tagfile_ignore_comments()
   call writefile([

src/version.c

@@ -704,6 +704,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    565,
 /**/
     564,
 /**/