Small windows with scroll-step set

The problem described in <http://www.xemacs.org/list-archives/xemacs-beta/200003/msg00645.html> is still occurring for me sometimes. This causes random crashes if you have a value set for scroll-step. One way that I've made it happen, although not every time, is to run XEmacs -vanilla, immediately use M-: (i.e., don't type into the *scratch* buffer) to set toolbar-visible-p and gutter-buffers-tab-visible-p to nil and scroll-step to 15, then do a File->Save As. This doesn't make much sense to do since it tries to save the default *scratch* buffer, but it sometimes causes the crash. The patch below avoids this problem. It occurs if the height of a window is so small that not even one line can be formatted in it. In this case the line cache will always be empty and point-in-line-start-cache will return -1 which was causing vmotion-1 to assert. I looked at the various callers of vmotion-1 and it appears that it is reasonable to just have it return the input point unchanged in this case, so that's what I did. If this is not the right thing to do, I'd be happy to hear alternative suggestions. Mike 2000-04-29 Mike Alexander <mta(a)arbortext.com&gt; * indent.c (vmotion_1): If point_in_line_start_cache fails simply return the input position instead of asserting out. Index: src/indent.c =================================================================== RCS file: /usr/CVSroot/XEmacs/xemacs/src/indent.c,v retrieving revision 1.9.2.4 diff -u -r1.9.2.4 indent.c --- indent.c 2000/02/07 07:59:19 1.9.2.4 +++ indent.c 2000/04/29 06:58:00 ＠＠ -624,8 +624,15 ＠＠ /* #### This assertion must be true before the if statements are hit but may possibly be wrong after the call to point_in_line_start_cache if orig is outside of the visible - region of the buffer. Handle this. */ - assert (elt >= 0); + region of the buffer. Handle this. + + This occurs sometimes if scroll-step is non-zero and the window + is very small. In this case it's not possible to lay out any lines + in the window and point_in_line_start_cache returns -1 because + the line cache is empty. In this case we will just return the + original point and hope for the best. */ + if (elt < 0) + return orig; /* Moving downward. */ if (vtarget > 0)