Re: [BUG] cdpath=(.) breaks cd from / on Cygwin

[Andrew Janke <janke@pobox.com>]

Looks good to me. When I build with this patch, cd from / on Cygwin 
works as expected, even with an explicit '.' in $cdpath.

Thanks!

Andrew


On 2/15/15 5:57 PM, Bart Schaefer wrote:
> On Feb 15,  3:18pm, Andrew Janke wrote:
> }
> } In Src/builtin.c, function cd_try_chdir(), lines 1080-1093, there's some
> } special case handling for Cygwin and the prefix '/'. But when the prefix
> } is '.', it goes down a different code path. It constructs the path
> } starting from pwd (which is '/' in this case), and then goes through the
> } path normalization which elides '.' segments. But it doesn't have a
> } special case check for Cygwin to check for leading '/' again. And I
> } think the elision of the first '.' segment will result in a computed
> } path starting with '//' but not further escaped.
>
> That's a pretty close analysis.  The real problem is that when pwd is
> "/", cd_try_chdir() unnecessarily inserts yet another "/" into the
> path before appending a cdpath segment (the "pfix").  So the path has
> already become "//./" before normalization even begins.  This is a
> waste of effort when pwd is "/" on any platform.
>
> I'm not sure why we bother compiling different branches for cygwin and
> otherwise in cd_try_chdir().  Doesn't appear the cygwin variation would
> be wrong anywhere else.  But I won't mess with that here.
>
> Try this patch:
>
>
> diff --git a/Src/builtin.c b/Src/builtin.c
> index c4e4b94..614b17d 100644
> --- a/Src/builtin.c
> +++ b/Src/builtin.c
> @@ -1093,9 +1093,11 @@ cd_try_chdir(char *pfix, char *dest, int hard)
>   	} else {
>   	    int pfl = strlen(pfix);
>   	    dlen = strlen(pwd);
> -
> +	    if (dlen == 1 && *pwd == '/')
> +		dlen = 0;
>   	    buf = zalloc(dlen + pfl + strlen(dest) + 3);
> -	    strcpy(buf, pwd);
> +	    if (dlen)
> +		strcpy(buf, pwd);
>   	    buf[dlen] = '/';
>   	    strcpy(buf + dlen + 1, pfix);
>   	    buf[dlen + 1 + pfl] = '/';