Re: [Bug-readline] Search with multibyte characters broken with custom rl_getc_function() (with analysis)

[Chet Ramey]

On 2/23/15 11:13 PM, Ulf Magnusson wrote:
> text.c has the following comment:
> 
> /* Bytes too short to compose character, try to wait for next byte.
>    Restore the state of the byte sequence, because in this case the
>    effect of mbstate is undefined. */
> 
> However, there doesn't seem to be corresponding handling for the search case.
> If e.g. the first byte of an UTF-8 'ö' (0xC3 0xB6) character is input during
> incremental search, it ends up in the following code in input.c:
> 
> if (_rl_get_char_len (mb, &ps) == -2)
>   {
>     /* Read more for multibyte character */
>     RL_SETSTATE (RL_STATE_MOREINPUT);
>     c = rl_read_key ();
>     RL_UNSETSTATE (RL_STATE_MOREINPUT);
>   }
> 
> rl_read_key() will in turn call rl_getc_function() -- without checking if
> there's any input available. 

Yes.  In all but the rarest cases, a partially-composed multibyte
character will not require waiting for more input to be available, because
the remainder will already be in the input buffer, so the incremental
search code doesn't bother.  I don't consider this a bug.

Using rl_input_available is not a good synchronization mechanism for this
case.  I'll have to think about what to do with it.

-- 
``The lyf so short, the craft so long to lerne.'' - Chaucer
                 ``Ars longa, vita brevis'' - Hippocrates
Chet Ramey, ITS, CWRU    address@hidden    http://cnswww.cns.cwru.edu/~chet/