Re: crash in display, triggered by calendar

[Ed Reingold <reingold@emr.cs.iit.edu>]

Does the error below (the crash) occur in earlier releases--version 20, say?  
It hasn't happened to me.

The diary processing code does NOT require that diary-file be writable or start
with a newline.  At least it is not supposed to.  However, if the file does not
begin and end with newlines they MUST be added or the simple diary display
mechanism (selective display) cannot work; but this is done in a protected way,
however (at least I thought it was).

Since I still use version 20, I will need help in figuring out the error.

By the way, if I had my druthers, there would be no simple diary display, only 
the fancy one, and the problem would not exist.  The simple display is and has 
always been a problem; I added it at RMS's insistence.

> GNU Emacs 21.3.50.22 (i686-pc-linux-gnu, X toolkit, Xaw3d scroll bars)
>  of 2002-08-06 on glip.premonitia.com
> 
> in the CVS head emacs, build a minute ago:
> 
> emacs has a long-standing bug: diary requires that diary-file 
> (normally "~/.diary") to be writable or to start with a newline

> Now this old bug triggers a crash.
> 
> $ cd ~
> $ mv .diary .diary.tmp
> $ echo ';' > .diary
> $ cat .diary.tmp >> .diary
> $ rm -f .diary.tmp
> $ chmod -w .diary
> $ emacs
> M-x calendar
> M-x view-diary-entries
> 
> you will get a message in the minibuffer that #<buffer .diary> is
> read-only (even if you set debug-on-error to t, you will not get a
> backtrace!)
> 
> C-x b .diary RET
> 
> ===> CRASH!!!
> 
> 
> Program received signal SIGSEGV, Segmentation fault.
> next_element_from_buffer (it=0xbfffe3f0) at xdisp.c:4819
> 4819      int success_p = 1;
> (gdb) where
> #0  next_element_from_buffer (it=0xbfffe3f0) at xdisp.c:4819
> #1  0x08060b88 in get_next_display_element (it=0xbfffe3f0) at xdisp.c:4213
> #2  0x0806053f in forward_to_next_line_start (it=0xbfffe3f0, 
>     skipped_p=0xbf8000a8) at xdisp.c:3871
> #3  0x08060781 in reseat_at_next_visible_line_start (it=0xbfffe3f0, 
>     on_newline_p=1) at xdisp.c:3996
> #4  0x0806165b in next_element_from_ellipsis (it=0xbfffe3f0) at xdisp.c:4775
> #5  0x080618eb in next_element_from_buffer (it=0xbfffe3f0) at xdisp.c:4909
> #6  0x08060b88 in get_next_display_element (it=0xbfffe3f0) at xdisp.c:4213
> #7  0x080618eb in next_element_from_buffer (it=0xbfffe3f0) at xdisp.c:4909
> #8  0x08060b88 in get_next_display_element (it=0xbfffe3f0) at xdisp.c:4213
> #9  0x080618eb in next_element_from_buffer (it=0xbfffe3f0) at xdisp.c:4909
> #10 0x08060b88 in get_next_display_element (it=0xbfffe3f0) at xdisp.c:4213
> #11 0x080618eb in next_element_from_buffer (it=0xbfffe3f0) at xdisp.c:4909
> #12 0x08060b88 in get_next_display_element (it=0xbfffe3f0) at xdisp.c:4213
> #13 0x080618eb in next_element_from_buffer (it=0xbfffe3f0) at xdisp.c:4909
> #14 0x08060b88 in get_next_display_element (it=0xbfffe3f0) at xdisp.c:4213
> #15 0x080618eb in next_element_from_buffer (it=0xbfffe3f0) at xdisp.c:4909
> #16 0x08060b88 in get_next_display_element (it=0xbfffe3f0) at xdisp.c:4213
> #17 0x080618eb in next_element_from_buffer (it=0xbfffe3f0) at xdisp.c:4909
> #18 0x08060b88 in get_next_display_element (it=0xbfffe3f0) at xdisp.c:4213
> #19 0x080618eb in next_element_from_buffer (it=0xbfffe3f0) at xdisp.c:4909
> #20 0x08060b88 in get_next_display_element (it=0xbfffe3f0) at xdisp.c:4213
> #21 0x080618eb in next_element_from_buffer (it=0xbfffe3f0) at xdisp.c:4909
> #22 0x08060b88 in get_next_display_element (it=0xbfffe3f0) at xdisp.c:4213
> #23 0x080618eb in next_element_from_buffer (it=0xbfffe3f0) at xdisp.c:4909
> #24 0x08060b88 in get_next_display_element (it=0xbfffe3f0) at xdisp.c:4213
> #25 0x080618eb in next_element_from_buffer (it=0xbfffe3f0) at xdisp.c:4909
> #26 0x08060b88 in get_next_display_element (it=0xbfffe3f0) at xdisp.c:4213
> #27 0x080618eb in next_element_from_buffer (it=0xbfffe3f0) at xdisp.c:4909
> #28 0x08060b88 in get_next_display_element (it=0xbfffe3f0) at xdisp.c:4213
> #29 0x080618eb in next_element_from_buffer (it=0xbfffe3f0) at xdisp.c:4909
> #30 0x08060b88 in get_next_display_element (it=0xbfffe3f0) at xdisp.c:4213
> #31 0x080618eb in next_element_from_buffer (it=0xbfffe3f0) at xdisp.c:4909
> #32 0x08060b88 in get_next_display_element (it=0xbfffe3f0) at xdisp.c:4213
> #33 0x080618eb in next_element_from_buffer (it=0xbfffe3f0) at xdisp.c:4909
> #34 0x08060b88 in get_next_display_element (it=0xbfffe3f0) at xdisp.c:4213
> #35 0x080618eb in next_element_from_buffer (it=0xbfffe3f0) at xdisp.c:4909
> #36 0x08060b88 in get_next_display_element (it=0xbfffe3f0) at xdisp.c:4213
> #37 0x080618eb in next_element_from_buffer (it=0xbfffe3f0) at xdisp.c:4909
> #38 0x08060b88 in get_next_display_element (it=0xbfffe3f0) at xdisp.c:4213
> #39 0x080618eb in next_element_from_buffer (it=0xbfffe3f0) at xdisp.c:4909
> #40 0x08060b88 in get_next_display_element (it=0xbfffe3f0) at xdisp.c:4213
> #41 0x080618eb in next_element_from_buffer (it=0xbfffe3f0) at xdisp.c:4909
> #42 0x08060b88 in get_next_display_element (it=0xbfffe3f0) at xdisp.c:4213
> #43 0x080618eb in next_element_from_buffer (it=0xbfffe3f0) at xdisp.c:4909
> #44 0x08060b88 in get_next_display_element (it=0xbfffe3f0) at xdisp.c:4213
> #45 0x080618eb in next_element_from_buffer (it=0xbfffe3f0) at xdisp.c:4909
> #46 0x08060b88 in get_next_display_element (it=0xbfffe3f0) at xdisp.c:4213
> #47 0x080618eb in next_element_from_buffer (it=0xbfffe3f0) at xdisp.c:4909
> #48 0x08060b88 in get_next_display_element (it=0xbfffe3f0) at xdisp.c:4213
> #49 0x080618eb in next_element_from_buffer (it=0xbfffe3f0) at xdisp.c:4909
> #50 0x08060b88 in get_next_display_element (it=0xbfffe3f0) at xdisp.c:4213
> #51 0x080618eb in next_element_from_buffer (it=0xbfffe3f0) at xdisp.c:4909
> #52 0x08060b88 in get_next_display_element (it=0xbfffe3f0) at xdisp.c:4213
> #53 0x080618eb in next_element_from_buffer (it=0xbfffe3f0) at xdisp.c:4909
> #54 0x08060b88 in get_next_display_element (it=0xbfffe3f0) at xdisp.c:4213
> #55 0x080618eb in next_element_from_buffer (it=0xbfffe3f0) at xdisp.c:4909
> #56 0x08060b88 in get_next_display_element (it=0xbfffe3f0) at xdisp.c:4213
> ---Type <return> to continue, or q <return> to quit---
> #57 0x080618eb in next_element_from_buffer (it=0xbfffe3f0) at xdisp.c:4909
> #58 0x08060b88 in get_next_display_element (it=0xbfffe3f0) at xdisp.c:4213
> #59 0x080618eb in next_element_from_buffer (it=0xbfffe3f0) at xdisp.c:4909
> #60 0x08060b88 in get_next_display_element (it=0xbfffe3f0) at xdisp.c:4213
> #61 0x080618eb in next_element_from_buffer (it=0xbfffe3f0) at xdisp.c:4909
> #62 0x08060b88 in get_next_display_element (it=0xbfffe3f0) at xdisp.c:4213
> #63 0x080618eb in next_element_from_buffer (it=0xbfffe3f0) at xdisp.c:4909
> #64 0x08060b88 in get_next_display_element (it=0xbfffe3f0) at xdisp.c:4213
> #65 0x080618eb in next_element_from_buffer (it=0xbfffe3f0) at xdisp.c:4909
> #66 0x08060b88 in get_next_display_element (it=0xbfffe3f0) at xdisp.c:4213
> #67 0x080618eb in next_element_from_buffer (it=0xbfffe3f0) at xdisp.c:4909
> #68 0x08060b88 in get_next_display_element (it=0xbfffe3f0) at xdisp.c:4213
> #69 0x080618eb in next_element_from_buffer (it=0xbfffe3f0) at xdisp.c:4909
> #70 0x08060b88 in get_next_display_element (it=0xbfffe3f0) at xdisp.c:4213
> #71 0x080618eb in next_element_from_buffer (it=0xbfffe3f0) at xdisp.c:4909
> #72 0x08060b88 in get_next_display_element (it=0xbfffe3f0) at xdisp.c:4213
> #73 0x080618eb in next_element_from_buffer (it=0xbfffe3f0) at xdisp.c:4909
> #74 0x08060b88 in get_next_display_element (it=0xbfffe3f0) at xdisp.c:4213
> #75 0x080618eb in next_element_from_buffer (it=0xbfffe3f0) at xdisp.c:4909
> #76 0x08060b88 in get_next_display_element (it=0xbfffe3f0) at xdisp.c:4213
> #77 0x080618eb in next_element_from_buffer (it=0xbfffe3f0) at xdisp.c:4909
> #78 0x08060b88 in get_next_display_element (it=0xbfffe3f0) at xdisp.c:4213
> #79 0x080618eb in next_element_from_buffer (it=0xbfffe3f0) at xdisp.c:4909
> #80 0x08060b88 in get_next_display_element (it=0xbfffe3f0) at xdisp.c:4213
> #81 0x080618eb in next_element_from_buffer (it=0xbfffe3f0) at xdisp.c:4909
> #82 0x08060b88 in get_next_display_element (it=0xbfffe3f0) at xdisp.c:4213
> #83 0x080618eb in next_element_from_buffer (it=0xbfffe3f0) at xdisp.c:4909
> #84 0x08060b88 in get_next_display_element (it=0xbfffe3f0) at xdisp.c:4213
> #85 0x080618eb in next_element_from_buffer (it=0xbfffe3f0) at xdisp.c:4909
> #86 0x08060b88 in get_next_display_element (it=0xbfffe3f0) at xdisp.c:4213
> #87 0x080618eb in next_element_from_buffer (it=0xbfffe3f0) at xdisp.c:4909
> #88 0x08060b88 in get_next_display_element (it=0xbfffe3f0) at xdisp.c:4213
> #89 0x080618eb in next_element_from_buffer (it=0xbfffe3f0) at xdisp.c:4909
> #90 0x08060b88 in get_next_display_element (it=0xbfffe3f0) at xdisp.c:4213
> #91 0x080618eb in next_element_from_buffer (it=0xbfffe3f0) at xdisp.c:4909
> #92 0x08060b88 in get_next_display_element (it=0xbfffe3f0) at xdisp.c:4213
> #93 0x080618eb in next_element_from_buffer (it=0xbfffe3f0) at xdisp.c:4909
> #94 0x08060b88 in get_next_display_element (it=0xbfffe3f0) at xdisp.c:4213
> #95 0x080618eb in next_element_from_buffer (it=0xbfffe3f0) at xdisp.c:4909
> #96 0x08060b88 in get_next_display_element (it=0xbfffe3f0) at xdisp.c:4213
> #97 0x080618eb in next_element_from_buffer (it=0xbfffe3f0) at xdisp.c:4909
> #98 0x08060b88 in get_next_display_element (it=0xbfffe3f0) at xdisp.c:4213
> #99 0x080618eb in next_element_from_buffer (it=0xbfffe3f0) at xdisp.c:4909
> #100 0x08060b88 in get_next_display_element (it=0xbfffe3f0) at xdisp.c:4213
> #101 0x080618eb in next_element_from_buffer (it=0xbfffe3f0) at xdisp.c:4909
> #102 0x08060b88 in get_next_display_element (it=0xbfffe3f0) at xdisp.c:4213
> #103 0x080618eb in next_element_from_buffer (it=0xbfffe3f0) at xdisp.c:4909
> #104 0x08060b88 in get_next_display_element (it=0xbfffe3f0) at xdisp.c:4213
> #105 0x080618eb in next_element_from_buffer (it=0xbfffe3f0) at xdisp.c:4909
> #106 0x08060b88 in get_next_display_element (it=0xbfffe3f0) at xdisp.c:4213
> #107 0x080618eb in next_element_from_buffer (it=0xbfffe3f0) at xdisp.c:4909
> #108 0x08060b88 in get_next_display_element (it=0xbfffe3f0) at xdisp.c:4213
> #109 0x080618eb in next_element_from_buffer (it=0xbfffe3f0) at xdisp.c:4909
> #110 0x08060b88 in get_next_display_element (it=0xbfffe3f0) at xdisp.c:4213
> #111 0x080618eb in next_element_from_buffer (it=0xbfffe3f0) at xdisp.c:4909
> #112 0x08060b88 in get_next_display_element (it=0xbfffe3f0) at xdisp.c:4213
> #113 0x080618eb in next_element_from_buffer (it=0xbfffe3f0) at xdisp.c:4909
> #114 0x08060b88 in get_next_display_element (it=0xbfffe3f0) at xdisp.c:4213
> #115 0x080618eb in next_element_from_buffer (it=0xbfffe3f0) at xdisp.c:4909
> ---Type <return> to continue, or q <return> to quit---q
> Quit
> (gdb) p it
> $3 = (struct it *) 0xbfffe3f0
> (gdb) p *it
> $4 = {
>   window = 1212942904, 
>   w = 0x84c0a38, 
>   f = 0x84c0910, 
>   method = 0x80616a4 <next_element_from_buffer>, 
>   stop_charpos = 5866, 
>   end_charpos = 5866, 
>   s = 0x0, 
>   string_nchars = 0, 
>   region_beg_charpos = -1, 
>   region_end_charpos = -1, 
>   redisplay_end_trigger_charpos = 0, 
>   multibyte_p = 1, 
>   header_line_p = 0, 
>   string_from_display_prop_p = 0, 
>   dp = 0x82d3f88, 
>   dpvec = 0x0, 
>   dpend = 0xbfffe43c, 
>   dpvec_char_len = 1, 
>   saved_face_id = 0, 
>   ctl_chars = {94, 77, 0 <repeats 14 times>}, 
>   current = {
>     pos = {
>       charpos = 5865, 
>       bytepos = 5865
>     }, 
>     overlay_string_index = -1, 
>     string_pos = {
>       charpos = -1, 
>       bytepos = -1
>     }, 
>     dpvec_index = -1
>   }, 
>   overlay_strings = {0, 0, 0}, 
>   n_overlay_strings = 0, 
>   string = 405361476, 
>   stack = {{
>       stop_charpos = 0, 
>       face_id = 0, 
>       string = 0, 
>       pos = {
>         pos = {
>           charpos = 0, 
>           bytepos = 0
>         }, 
>         overlay_string_index = 0, 
>         string_pos = {
>           charpos = 0, 
>           bytepos = 0
>         }, 
>         dpvec_index = 0
>       }, 
>       end_charpos = 0, 
>       string_nchars = 0, 
>       area = LEFT_MARGIN_AREA, 
>       multibyte_p = 0, 
>       string_from_display_prop_p = 0, 
>       display_ellipsis_p = 0, 
>       space_width = 0, 
> ---Type <return> to continue, or q <return> to quit---
>       voffset = 0, 
>       font_height = 0
>     }, {
>       stop_charpos = 0, 
>       face_id = 0, 
>       string = 0, 
>       pos = {
>         pos = {
>           charpos = 0, 
>           bytepos = 0
>         }, 
>         overlay_string_index = 0, 
>         string_pos = {
>           charpos = 0, 
>           bytepos = 0
>         }, 
>         dpvec_index = 0
>       }, 
>       end_charpos = 0, 
>       string_nchars = 0, 
>       area = LEFT_MARGIN_AREA, 
>       multibyte_p = 0, 
>       string_from_display_prop_p = 0, 
>       display_ellipsis_p = 0, 
>       space_width = 0, 
>       voffset = 0, 
>       font_height = 0
>     }}, 
>   sp = 0, 
>   selective_display_ellipsis_p = 0, 
>   ctl_arrow_p = 1, 
>   selective = 0, 
>   what = IT_CHARACTER, 
>   face_id = 0, 
>   face_box_p = 0, 
>   start_of_box_run_p = 0, 
>   end_of_box_run_p = 0, 
>   overlay_strings_at_end_processed_p = 1, 
>   glyph_not_available_p = 0, 
>   starts_in_middle_of_char_p = 0, 
>   face_before_selective_p = 1, 
>   base_face_id = 0, 
>   c = 13, 
>   len = 1, 
>   cmp_id = 0, 
>   cmp_len = 0, 
>   char_to_display = 33, 
>   image_id = 0, 
>   space_width = 405361476, 
>   voffset = 0, 
>   font_height = 405361476, 
>   object = 1215887680, 
>   position = {
>     charpos = 5865, 
>     bytepos = 5865
>   }, 
>   truncate_lines_p = 0, 
>   tab_width = 8, 
>   truncation_pixel_width = 0, 
> ---Type <return> to continue, or q <return> to quit---
>   continuation_pixel_width = 0, 
>   first_visible_x = 0, 
>   last_visible_x = 480, 
>   last_visible_y = 725, 
>   extra_line_spacing = 0, 
>   glyph_row = 0x84d149c, 
>   area = TEXT_AREA, 
>   nglyphs = 1, 
>   pixel_width = 6, 
>   ascent = 11, 
>   descent = 2, 
>   max_ascent = 11, 
>   max_descent = 2, 
>   phys_ascent = 9, 
>   phys_descent = 0, 
>   max_phys_ascent = 11, 
>   max_phys_descent = 2, 
>   current_x = 402, 
>   continuation_lines_width = 0, 
>   current_y = 91, 
>   vpos = 7, 
>   hpos = 59
> }
> 
> 
> 
>  
> 
> -- 
> Sam Steingold (http://www.podval.org/~sds) running RedHat7.3 GNU/Linux
> <http://www.camera.org> <http://www.iris.org.il> <http://www.memri.org/>
> <http://www.mideasttruth.com/> <http://www.palestine-central.com/links.html>
> Are you smart enough to use Lisp?
> 
> 
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