To: vim_dev@googlegroups.com
Subject: Patch 9.0.1664
Fcc: outbox
From: Bram Moolenaar <Bram@moolenaar.net>
Mime-Version: 1.0
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------------

Patch 9.0.1664
Problem:    Divide by zero when scrolling with 'smoothscroll' set.
Solution:   Avoid using a negative width. (closes #12540, closes #12528)
Files:      src/move.c, src/testdir/test_scroll_opt.vim,
            src/testdir/dumps/Test_smoothscroll_zero_bot.dump


*** ../vim-9.0.1663/src/move.c	2023-06-05 20:44:34.734261086 +0100
--- src/move.c	2023-06-24 21:26:52.197184691 +0100
***************
*** 2591,2607 ****
  					(curwin, curwin->w_topline, FALSE);
  	    int skip_lines = 0;
  	    int width1 = curwin->w_width - curwin_col_off();
! 	    int width2 = width1 + curwin_col_off2();
! 	    // similar formula is used in curs_columns()
! 	    if (curwin->w_skipcol > width1)
! 		skip_lines += (curwin->w_skipcol - width1) / width2 + 1;
! 	    else if (curwin->w_skipcol > 0)
! 		skip_lines = 1;
! 
! 	    top_plines -= skip_lines;
! 	    if (top_plines > curwin->w_height)
  	    {
! 		scrolled += (top_plines - curwin->w_height);
  	    }
  	}
      }
--- 2591,2610 ----
  					(curwin, curwin->w_topline, FALSE);
  	    int skip_lines = 0;
  	    int width1 = curwin->w_width - curwin_col_off();
! 	    if (width1 > 0)
  	    {
! 		int width2 = width1 + curwin_col_off2();
! 		// similar formula is used in curs_columns()
! 		if (curwin->w_skipcol > width1)
! 		    skip_lines += (curwin->w_skipcol - width1) / width2 + 1;
! 		else if (curwin->w_skipcol > 0)
! 		    skip_lines = 1;
! 
! 		top_plines -= skip_lines;
! 		if (top_plines > curwin->w_height)
! 		{
! 		    scrolled += (top_plines - curwin->w_height);
! 		}
  	    }
  	}
      }
*** ../vim-9.0.1663/src/testdir/test_scroll_opt.vim	2023-06-05 20:44:34.734261086 +0100
--- src/testdir/test_scroll_opt.vim	2023-06-24 21:53:20.891302303 +0100
***************
*** 833,836 ****
--- 833,860 ----
    call StopVimInTerminal(buf)
  endfunc
  
+ " this was dividing by zero bug in scroll_cursor_bot
+ func Test_smoothscroll_zero_width_scroll_cursor_bot()
+   CheckScreendump
+ 
+   let lines =<< trim END
+       silent normal yy
+       silent normal 19p
+       winsize 0 19
+       vsplit
+       vertical resize 0
+       set foldcolumn=1
+       set number
+       set smoothscroll
+       silent normal 20G
+   END
+   call writefile(lines, 'XSmoothScrollZeroBot', 'D')
+   let buf = RunVimInTerminal('-u NONE -S XSmoothScrollZeroBot', #{rows: 19, wait_for_ruler: 0})
+   call TermWait(buf, 1000)
+ 
+   call VerifyScreenDump(buf, 'Test_smoothscroll_zero_bot', {})
+ 
+   call StopVimInTerminal(buf)
+ endfunc
+ 
  " vim: shiftwidth=2 sts=2 expandtab
*** ../vim-9.0.1663/src/testdir/dumps/Test_smoothscroll_zero_bot.dump	2023-06-24 21:57:31.519185073 +0100
--- src/testdir/dumps/Test_smoothscroll_zero_bot.dump	2023-06-24 21:26:52.197184691 +0100
***************
*** 0 ****
--- 1,19 ----
+ | +0#af5f00255#ffffff0||+1#0000000&| +0&&@9
+ |@+0#4040ff13&||+1#0000000&| +0&&@9
+ |@+0#4040ff13&||+1#0000000&| +0&&@9
+ |@+0#4040ff13&||+1#0000000&| +0&&@9
+ |@+0#4040ff13&||+1#0000000&| +0&&@9
+ |@+0#4040ff13&||+1#0000000&| +0&&@9
+ |@+0#4040ff13&||+1#0000000&| +0&&@9
+ |@+0#4040ff13&||+1#0000000&| +0&&@9
+ |@+0#4040ff13&||+1#0000000&| +0&&@9
+ |@+0#4040ff13&||+1#0000000&| +0&&@9
+ |@+0#4040ff13&||+1#0000000&| +0&&@9
+ |@+0#4040ff13&||+1#0000000&| +0&&@9
+ |@+0#4040ff13&||+1#0000000&| +0&&@9
+ |@+0#4040ff13&||+1#0000000&| +0&&@9
+ |@+0#4040ff13&||+1#0000000&| +0&&@9
+ |@+0#4040ff13&||+1#0000000&| +0&&@9
+ >@+0#4040ff13&||+1#0000000&| +0&&@9
+ |<+3&&| |<+1&&|a|m|e|]| |[|+|]| 
+ | +0&&@11
*** ../vim-9.0.1663/src/version.c	2023-06-24 20:02:21.503021810 +0100
--- src/version.c	2023-06-24 21:57:12.587193552 +0100
***************
*** 697,698 ****
--- 697,700 ----
  {   /* Add new patch number below this line */
+ /**/
+     1664,
  /**/

-- 
The term "free software" is defined by Richard M. Stallman as
being software that isn't necessarily for free.  Confusing?
Let's call it "Stallman software" then!
				-- Bram Moolenaar

 /// Bram Moolenaar -- Bram@Moolenaar.net -- http://www.Moolenaar.net   \\\
///                                                                      \\\
\\\        sponsor Vim, vote for features -- http://www.Vim.org/sponsor/ ///
 \\\            help me help AIDS victims -- http://ICCF-Holland.org    ///