Re: Bug#74278: info: Segfault if return key pressed in "SEE ALSO" section

[H. Nanosecond]

The problem is from the below bit of code.

If the cursor is before the first reference when you press enter
then the variable 'which' will be -1 after the loop,
causing a memory error when refs[which] is accessed.

SEE ALSO
   X    apropos(1), whatis(1), less(1), groff(1).
   ^ cursor here.

>I get a segfault when I run info on a command such as "as" or "man"
>that has only a man page, move the curson into the "SEE ALSO"
>section and press the Enter key.

At texinfo-4.0/info/session.c line 2043:

              {
                int which = 0;

                /* Find the closest reference to point. */
                if (builder == info_xrefs_of_node)
                  {
                    int closest = -1;

                    for (; refs[which]; which++)
                      {
                        if ((window->point >= refs[which]->start) &&
                            (window->point <= refs[which]->end))
                          {
                            closest = which;
                            break;
                          }
                        else if (window->point < refs[which]->start)
                          {
                            break;
                          }
                      }
                    if (closest == -1)
                      which--;
                    else
                      which = closest;
                  }

                defentry = (REFERENCE *)xmalloc (sizeof (REFERENCE));
                defentry->label = xstrdup (refs[which]->label);
                defentry->filename = refs[which]->filename;
                defentry->nodename = refs[which]->nodename;