Re: (aset UNIBYTE-STRING MULTIBYTE-CHAR)

[Harald Hanche-Olsen]

This works as it should in the latest CVS:

(setq foo (make-string 4 ?a))
(aset foo 1 ?€) ; <= that's a euro sign

But this fails:

(setq foo (make-string 4 ?a))
(aset foo 1 ?å)
(aset foo 1 ?€) ; => Error: args out of range

The problem seems to lie in these lines (2095-2107) from data.c:

      if (XINT (newelt) >= 0 && ! SINGLE_BYTE_CHAR_P (XINT (newelt)))
        {
          int i;

          for (i = SBYTES (array) - 1; i >= 0; i--)
            if (SREF (array, i) >= 0x80)
              args_out_of_range (array, newelt);
          /* ARRAY is an ASCII string.  Convert it to a multibyte
             string, and try `aset' again.  */
          STRING_SET_MULTIBYTE (array);
          return Faset (array, idx, newelt);
        }
      SSET (array, idxval, XINT (newelt));

I am sure the test for members >= 0x80 is there for a good reason, but
it clearly screws up this case and makes the fix rather less useful
than it should have been. I don't know emacs internals well enough to
suggest a fix.

And yes, this did bite in real life: It caused mew to choke on a
malformed spam email. No disaster obviously, but inconvenient.

- Harald

PS. My apologies for messing up threading; I wasn't on the list when
the message I am responding to was posted on 2008-07-15, so I don't
know its message-id.