Subject: bug#6378: all-completions Segfault

From: Stefan Monnier <[email-masked]>
Date: Tue, 08 Jun 2010 16:30:52 -0400

> Although I don't understand why the code-path for the vector
> version can't be simplified as in the following patch, which also
> fixes the problem AFAICT:

> diff --git a/src/minibuf.c b/src/minibuf.c
> index ad81bfd..c6aae27 100644
> --- a/src/minibuf.c
> +++ b/src/minibuf.c
> @@ -1610,22 +1610,14 @@ with a space are ignored unless STRING itself starts with a space.  */)
>  	}
>        else if (type == 2)
>  	{
> -	  if (!EQ (bucket, zero))
> -	    {
> -	      elt = bucket;
> -	      eltstring = elt;
> -	      if (XSYMBOL (bucket)->next)
> -		XSETSYMBOL (bucket, XSYMBOL (bucket)->next);
> -	      else
> -		XSETFASTINT (bucket, 0);
> -	    }
> -	  else if (++index >= obsize)
> -	    break;
> -	  else
> -	    {
> -	      bucket = XVECTOR (collection)->contents[index];
> -	      continue;
> -	    }
> +          if ( index < obsize )
> +            {
> +              elt = bucket;
> +              eltstring = elt;
> +              bucket = XVECTOR (collection)->contents[++index];
> +            }
> +          else
> +            break;
>  	}
>        else /* if (type == 3) */
>  	{

IIUC this would only loop through all the buckets, without looping
through each bucket's linked list.
Compare (length obarray)
and     (let ((i 0)) (mapatoms (lambda (_) (incf i)) obarray) i)

        Stefan