patch 8.2.1598: starting a hidden terminal resizes the current window

Problem:    Starting a hidden terminal resizes the current window.
Solution:   Do not resize the current window for a hidden terminal.
            (closes #6872)
diff --git a/src/terminal.c b/src/terminal.c
index 7856ad5..cab9cb9 100644
--- a/src/terminal.c
+++ b/src/terminal.c
@@ -315,18 +315,22 @@
     else if (cols != 0)
 	term->tl_cols = cols;
 
-    if (term->tl_rows != curwin->w_height)
-	win_setheight_win(term->tl_rows, curwin);
-    if (term->tl_cols != curwin->w_width)
-	win_setwidth_win(term->tl_cols, curwin);
-
-    // Set 'winsize' now to avoid a resize at the next redraw.
-    if (!minsize && *curwin->w_p_tws != NUL)
+    if (!opt->jo_hidden)
     {
-	char_u buf[100];
+	if (term->tl_rows != curwin->w_height)
+	    win_setheight_win(term->tl_rows, curwin);
+	if (term->tl_cols != curwin->w_width)
+	    win_setwidth_win(term->tl_cols, curwin);
 
-	vim_snprintf((char *)buf, 100, "%dx%d", term->tl_rows, term->tl_cols);
-	set_option_value((char_u *)"termwinsize", 0L, buf, OPT_LOCAL);
+	// Set 'winsize' now to avoid a resize at the next redraw.
+	if (!minsize && *curwin->w_p_tws != NUL)
+	{
+	    char_u buf[100];
+
+	    vim_snprintf((char *)buf, 100, "%dx%d",
+						 term->tl_rows, term->tl_cols);
+	    set_option_value((char_u *)"termwinsize", 0L, buf, OPT_LOCAL);
+	}
     }
 }
 
diff --git a/src/testdir/test_terminal2.vim b/src/testdir/test_terminal2.vim
index a99818b..64310f6 100644
--- a/src/testdir/test_terminal2.vim
+++ b/src/testdir/test_terminal2.vim
@@ -130,6 +130,16 @@
   set termwinsize=
 endfunc
 
+" hidden terminal must not change current window size
+func Test_terminal_hidden_winsize()
+  let cmd = GetDummyCmd()
+  let rows = winheight(0)
+  let buf = term_start(cmd, #{hidden: 1, term_rows: 10})
+  call assert_equal(rows, winheight(0))
+  call assert_equal([10, &columns], term_getsize(buf))
+  exe "bwipe! " .. buf
+endfunc
+
 func Test_terminal_termwinkey()
   " make three tabpages, terminal in the middle
   0tabnew
diff --git a/src/version.c b/src/version.c
index 4dfad08..b6a6f41 100644
--- a/src/version.c
+++ b/src/version.c
@@ -755,6 +755,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1598,
+/**/
     1597,
 /**/
     1596,