Re: [PATCH] Fix hang if $OLDPWD points to inaccessible directory

[Chet Ramey]

On 10/3/17 4:14 PM, Mikulas Patocka wrote:
> 
> 
> On Sun, 1 Oct 2017, Chet Ramey wrote:
> 
>> On 9/30/17 4:20 AM, Mikulas Patocka wrote:
>>
>>> Is there some reason why do we need to check if $OLDPWD is a real 
>>> directory? dash and ksh accept the $OLDPWD variable, but don't poke it 
>>> with the stat syscall. zsh clears $OLDPWD.
>>
>> It makes no sense to inherit it if it doesn't name a directory (or
>> "pathname" in the Posix standard), other than the sort of lazy evaluation
>> that will prevent your particular problem.
> 
> Does something bad happen if we inherit $OLDPWD that points to a 
> non-existing directory? Will some script malfunction because of it?

`cd -' will fail, of course. That's where $OLDPWD gets used. And who
knows whether some script will fail? It's impossible to say.

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