Re: Bug#183730: zsh: setting SAVEHIST breaks history saving without warning

[Peter Stephenson <pws@csr.com>]

Clint Adams wrote:
> > Maybe there should be a truncation warning.
> > 
> > 1% SAVEHIST=899795648511
> > 2% print $SAVEHIST
> > 2147483647
> > 3% SAVEHIST=899795648512
> > 4% print $SAVEHIST
> 
> Or an error?

(Why does this `break history saving'?  Or is the subject line
inaccurate?  I'll assume the latter for now.)

I suspect there could be a lot of problems like this.  History numbering
ought to wrap gracefully, but I expect it doesn't.  Also, arithmetic is
done as a `zlong' which is probably 64 bits if the compiler supports
it, while the history size and many other parameters are only 32 bits.

Consequently there are lots of place which would need to change to make
this sort of thing consistent,
- the history code itself
- where integers from arithmetic expresssions are assigned to variables
  (though maybe it would be more consistent to use zlong for parameters
  set by the user)
- where numbers are originally parsed.

The number assigned is obviously too large to be directly useful; what
was the intention?  Always save values at the end of the history list
regardless of what was there already?

-- 
Peter Stephenson <pws@csr.com>                  Software Engineer
CSR Ltd., Science Park, Milton Road,
Cambridge, CB4 0WH, UK                          Tel: +44 (0)1223 692070


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