patch 8.0.1722: cannot specify a minimal size for a terminal window

Problem:    Cannot specify a minimal size for a terminal window.
Solution:   Support the "rows*cols" format for 'winsize'.

runtime/doc/options.txt

@@ -7960,15 +7960,23 @@ A jump table for the options with a short description can be found at |Q_op|.
 'termsize' 'tms'	string	(default "")
 			local to window
 			{not in Vi}
-	Size of the |terminal| window.  Format: {rows}x{columns}.
+	Size of the |terminal| window.  Format: {rows}x{columns} or
+	{rows}*{columns}.
 	- When empty the terminal gets the size from the window.
-	- When set (e.g., "24x80") the terminal size is not adjusted to the
-	  window size.  If the window is smaller only the top-left part is
-	  displayed.
-	  When rows is zero then use the height of the window.
-	  When columns is zero then use the width of the window.
-	  For example: "30x0" uses 30 rows with the current window width.
-	  Using "0x0" is the same as empty.
+	- When set with a "x" (e.g., "24x80") the terminal size is not
+	  adjusted to the window size.  If the window is smaller only the
+	  top-left part is displayed.
+	- When set with a "*" (e.g., "10*50") the terminal size follows the
+	  window size, but will not be smaller than the specified rows and/or
+	  columns.
+	- When rows is zero then use the height of the window.
+	- When columns is zero then use the width of the window.
+	- Using "0x0" or "0*0" is the same as empty.
+
+	Examples:
+	  "30x0" uses 30 rows and the current window width.
+	  "20*0" uses at least 20 rows and the current window width.
+	  "0*40" uses the current window height and at least 40 columns.
 	Note that the command running in the terminal window may still change
 	the size of the terminal.  In that case the Vim window will be
 	adjusted to that size, if possible.

src/option.c

@@ -7464,7 +7464,9 @@ did_set_string_option(
 	if (*curwin->w_p_tms != NUL)
 	{
 	    p = skipdigits(curwin->w_p_tms);
-	    if (p == curwin->w_p_tms || *p != 'x' || *skipdigits(p + 1) != NUL)
+	    if (p == curwin->w_p_tms
+		    || (*p != 'x' && *p != '*')
+		    || *skipdigits(p + 1) != NUL)
 		errmsg = e_invarg;
 	}
     }

src/terminal.c

@@ -42,26 +42,20 @@
  *   redirection.  Probably in call to channel_set_pipes().
  * - Win32: Redirecting output does not work, Test_terminal_redir_file()
  *   is disabled.
- * - Copy text in the vterm to the Vim buffer once in a while, so that
- *   completion works.
  * - When starting terminal window with shell in terminal, then using :gui to
  *   switch to GUI, shell stops working. Scrollback seems wrong, command
  *   running in shell is still running.
- * - in GUI vertical split causes problems.  Cursor is flickering. (Hirohito
- *   Higashi, 2017 Sep 19)
- * - after resizing windows overlap. (Boris Staletic, #2164)
- * - cursor blinks in terminal on widows with a timer. (xtal8, #2142)
- * - Termdebug does not work when Vim build with mzscheme.  gdb hangs.
- * - After executing a shell command the status line isn't redraw.
- * - add test for giving error for invalid 'termsize' value.
- * - support minimal size when 'termsize' is "rows*cols".
- * - support minimal size when 'termsize' is empty?
  * - GUI: when using tabs, focus in terminal, click on tab does not work.
+ * - Copy text in the vterm to the Vim buffer once in a while, so that
+ *   completion works.
  * - Redrawing is slow with Athena and Motif.  Also other GUI? (Ramel Eshed)
  * - For the GUI fill termios with default values, perhaps like pangoterm:
  *   http://bazaar.launchpad.net/~leonerd/pangoterm/trunk/view/head:/main.c#L134
  * - When 'encoding' is not utf-8, or the job is using another encoding, setup
  *   conversions.
+ * - Termdebug does not work when Vim build with mzscheme: gdb hangs just after
+ *   "run".  Everything else works, including communication channel.  Not
+ *   initializing mzscheme avoid the problem, thus it's not some #ifdef.
  */
 
 #include "vim.h"
@@ -133,9 +127,6 @@ struct terminal_S {
     /* last known vterm size */
     int		tl_rows;
     int		tl_cols;
-    /* vterm size does not follow window size */
-    int		tl_rows_fixed;
-    int		tl_cols_fixed;
 
     char_u	*tl_title; /* NULL or allocated */
     char_u	*tl_status_text; /* NULL or allocated */
@@ -207,9 +198,38 @@ static int	desired_cursor_blink = -1;
  * 1. Generic code for all systems.
  */
 
+/*
+ * Parse 'termsize' and set "rows" and "cols" for the terminal size in the
+ * current window.
+ * Sets "rows" and/or "cols" to zero when it should follow the window size.
+ * Return TRUE if the size is the minimum size: "24*80".
+ */
+    static int
+parse_termsize(win_T *wp, int *rows, int *cols)
+{
+    int	minsize = FALSE;
+
+    *rows = 0;
+    *cols = 0;
+
+    if (*wp->w_p_tms != NUL)
+    {
+	char_u *p = vim_strchr(wp->w_p_tms, 'x');
+
+	/* Syntax of value was already checked when it's set. */
+	if (p == NULL)
+	{
+	    minsize = TRUE;
+	    p = vim_strchr(wp->w_p_tms, '*');
+	}
+	*rows = atoi((char *)wp->w_p_tms);
+	*cols = atoi((char *)p + 1);
+    }
+    return minsize;
+}
+
 /*
  * Determine the terminal size from 'termsize' and the current window.
- * Assumes term->tl_rows and term->tl_cols are zero.
  */
     static void
 set_term_and_win_size(term_T *term)
@@ -224,27 +244,21 @@ set_term_and_win_size(term_T *term)
 	return;
     }
 #endif
-    if (*curwin->w_p_tms != NUL)
+    if (parse_termsize(curwin, &term->tl_rows, &term->tl_cols))
     {
-	char_u *p = vim_strchr(curwin->w_p_tms, 'x') + 1;
-
-	term->tl_rows = atoi((char *)curwin->w_p_tms);
-	term->tl_cols = atoi((char *)p);
+	if (term->tl_rows != 0)
+	    term->tl_rows = MAX(term->tl_rows, curwin->w_height);
+	if (term->tl_cols != 0)
+	    term->tl_cols = MAX(term->tl_cols, curwin->w_width);
     }
     if (term->tl_rows == 0)
 	term->tl_rows = curwin->w_height;
     else
-    {
 	win_setheight_win(term->tl_rows, curwin);
-	term->tl_rows_fixed = TRUE;
-    }
     if (term->tl_cols == 0)
 	term->tl_cols = curwin->w_width;
     else
-    {
 	win_setwidth_win(term->tl_cols, curwin);
-	term->tl_cols_fixed = TRUE;
-    }
 }
 
 /*
@@ -2853,6 +2867,10 @@ term_update_window(win_T *wp)
     VTermScreen *screen;
     VTermState	*state;
     VTermPos	pos;
+    int		rows, cols;
+    int		newrows, newcols;
+    int		minsize;
+    win_T	*twp;
 
     if (term == NULL || term->tl_vterm == NULL || term->tl_normal_mode)
 	return FAIL;
@@ -2871,31 +2889,32 @@ term_update_window(win_T *wp)
      * If the window was resized a redraw will be triggered and we get here.
      * Adjust the size of the vterm unless 'termsize' specifies a fixed size.
      */
-    if ((!term->tl_rows_fixed && term->tl_rows != wp->w_height)
-	    || (!term->tl_cols_fixed && term->tl_cols != wp->w_width))
-    {
-	int	rows = term->tl_rows_fixed ? term->tl_rows : wp->w_height;
-	int	cols = term->tl_cols_fixed ? term->tl_cols : wp->w_width;
-	win_T	*twp;
+    minsize = parse_termsize(wp, &rows, &cols);
 
-	FOR_ALL_WINDOWS(twp)
+    newrows = 99999;
+    newcols = 99999;
+    FOR_ALL_WINDOWS(twp)
+    {
+	/* When more than one window shows the same terminal, use the
+	 * smallest size. */
+	if (twp->w_buffer == term->tl_buffer)
 	{
-	    /* When more than one window shows the same terminal, use the
-	     * smallest size. */
-	    if (twp->w_buffer == term->tl_buffer)
-	    {
-		if (!term->tl_rows_fixed && rows > twp->w_height)
-		    rows = twp->w_height;
-		if (!term->tl_cols_fixed && cols > twp->w_width)
-		    cols = twp->w_width;
-	    }
+	    newrows = MIN(newrows, twp->w_height);
+	    newcols = MIN(newcols, twp->w_width);
 	}
+    }
+    newrows = rows == 0 ? newrows : minsize ? MAX(rows, newrows) : rows;
+    newcols = cols == 0 ? newcols : minsize ? MAX(cols, newcols) : cols;
+
+    if (term->tl_rows != newrows || term->tl_cols != newcols)
+    {
+
 
 	term->tl_vterm_size_changed = TRUE;
-	vterm_set_size(vterm, rows, cols);
+	vterm_set_size(vterm, newrows, newcols);
 	ch_log(term->tl_job->jv_channel, "Resizing terminal to %d lines",
-									 rows);
-	term_report_winsize(term, rows, cols);
+								      newrows);
+	term_report_winsize(term, newrows, newcols);
     }
 
     /* The cursor may have been moved when resizing. */

src/testdir/test_terminal.vim

@@ -1357,7 +1357,7 @@ func Test_terminal_ansicolors_func()
   exe buf . 'bwipe'
 endfunc
 
-func Test_terminal_termsize_option()
+func Test_terminal_termsize_option_fixed()
   if !CanRunVimInTerminal()
     return
   endif
@@ -1389,3 +1389,69 @@ func Test_terminal_termsize_option()
 
   set termsize=
 endfunc
+
+func Test_terminal_termsize_option_zero()
+  set termsize=0x0
+  let buf = Run_shell_in_terminal({})
+  let win = bufwinid(buf)
+  call assert_equal([winheight(win), winwidth(win)], term_getsize(buf))
+  call Stop_shell_in_terminal(buf)
+  call term_wait(buf)
+  exe buf . 'bwipe'
+
+  set termsize=7x0
+  let buf = Run_shell_in_terminal({})
+  let win = bufwinid(buf)
+  call assert_equal([7, winwidth(win)], term_getsize(buf))
+  call Stop_shell_in_terminal(buf)
+  call term_wait(buf)
+  exe buf . 'bwipe'
+
+  set termsize=0x33
+  let buf = Run_shell_in_terminal({})
+  let win = bufwinid(buf)
+  call assert_equal([winheight(win), 33], term_getsize(buf))
+  call Stop_shell_in_terminal(buf)
+  call term_wait(buf)
+  exe buf . 'bwipe'
+
+  set termsize=
+endfunc
+
+func Test_terminal_termsize_mininmum()
+  set termsize=10*50
+  vsplit
+  let buf = Run_shell_in_terminal({})
+  let win = bufwinid(buf)
+  call assert_inrange(10, 1000, winheight(win))
+  call assert_inrange(50, 1000, winwidth(win))
+  call assert_equal([winheight(win), winwidth(win)], term_getsize(buf))
+
+  resize 15
+  vertical resize 60
+  redraw
+  call assert_equal([15, 60], term_getsize(buf))
+  call assert_equal(15, winheight(win))
+  call assert_equal(60, winwidth(win))
+
+  resize 7
+  vertical resize 30
+  redraw
+  call assert_equal([10, 50], term_getsize(buf))
+  call assert_equal(7, winheight(win))
+  call assert_equal(30, winwidth(win))
+
+  call Stop_shell_in_terminal(buf)
+  call term_wait(buf)
+  exe buf . 'bwipe'
+
+  set termsize=0*0
+  let buf = Run_shell_in_terminal({})
+  let win = bufwinid(buf)
+  call assert_equal([winheight(win), winwidth(win)], term_getsize(buf))
+  call Stop_shell_in_terminal(buf)
+  call term_wait(buf)
+  exe buf . 'bwipe'
+
+  set termsize=
+endfunc

src/version.c

@@ -762,6 +762,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1722,
 /**/
     1721,
 /**/