Re: Bug: Wrong completion of $(( $(!cmd

[Peter Stephenson <pws@xxxxxxx>]

Bart Schaefer wrote:
> On Jan 23,  1:04pm, Peter Stephenson wrote:
> }
> } The problem is somewhere here (in lex.c). If dquote_parse() returns
> } non-zero it's an error indication, not a character, so the hungetc(c)
> } is definitely wrong in that case.
> 
> I don't think that's true.

I presume you mean the second statement.  If you've got any evidence
against the first statement I'd like to see it.

> If you look at the tail end of dquote_parse()
> you'll see that if lexstop is false the return value of dquote_parse() is
> overloaded -- it's both an error indication AND the most recently read
> character from the input stream.  That's what hungetc() is trying to put
> back in that spot in cmd_or_math().
> 
> That doesn't make it correct, but that's what's going on.  There must be
> (or have been at some past time) some other reason higher up the parse
> tree why that final character needed to be retained.

I looked a bit further and it seems it's used in gettokstr() to
hungetc() a character when we have an error.  I don't understand what
that buys when we can't parse the input anyway, particularly since we
don't even know if it's a valid character because of the other way of
setting the value; could it have been a hack to get history lines to be
stored properly after an error?  I recall we improved that at some
point, so this hack may not be necessary.

I traced it (the "err = c" thing in dquote_parse()) back in the code to
3.0.0, which is before the use in cmd_or_math() that is causing the
problem, so it wasn't introduced specifically for that, and
cmd_or_math() was roughly the way it now is right back in 3.0.8.
Consequently (although what you say is true) I don't see anything wrong
with the proposed change.

-- 
Peter Stephenson <pws@xxxxxxx>                  Software Engineer
CSR PLC, Churchill House, Cambridge Business Park, Cowley Road
Cambridge, CB4 0WZ, UK                          Tel: +44 (0)1223 692070


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