Re: [PATCH 2/2] git: continue alias lookup on EACCES errors

From: Junio C Hamano <gitster@pobox.com>
Date: Mar 28, 2012, 17:42 UTC
Message-ID: <7vaa30wrjx.fsf@alter.siamese.dyndns.org>
In-Reply-To: <20120328043058.GD30251@sigill.intra.peff.net>

Jeff King <peff@peff.net> writes:

Show 17 quoted lines

> On Tue, Mar 27, 2012 at 12:16:36PM -0700, Junio C Hamano wrote:
>
>> Jeff King <peff@peff.net> writes:
>> 
>> > If git receives an EACCES error while trying to execute an
>> > external command, we currently give up and report the error.
>> > However, the EACCES may be caused by an inaccessible
>> > directory in the user's PATH.
>> 
>> Regardless of EACCES/ENOENT change we discussed, the observable behaviour
>> should be testable.  Something like this?
>
> Yes, though I held back on writing tests, because I don't think we've
> quite decided what the behavior _should_ be. Should we be
> differentiating "chmod -x /bin/ls" from "chmod -x /bin"? Should we be
> continuing alias lookup on EACCES? Should we print edit-distance
> suggestions on EACCES?

I am leaning to think that it would be the least surprising if we treat as if /bin/ls does not even exist if /bin is not searchable. If /bin/ls is unreadable or unexecutable but /bin is searchable, then we _know_ it exists, and we follow the usual exec*p() rule to ignore it so "git ls" would try to find an alias and when all else fails will give the edit distance suggestions but should exclude /bin/ls from candidates. If /bin itself is unsearchable, we do not even know what it contains, so it is needless to say that /bin/ls will not be part of suggestion candidates.

That way, the only thing people _could_ complain about is "I have a directory $HOME/sillybin in my $PATH but do not have an executable bit on it. When I try to run 'git stupid', 'git-stupid' in that diretory is not executed, and I do not even get an error message to point out that I am missing the executable bit on $HOME/sillybin directory". And you can say "Ah, just like the shell. So make sure you have necessary permission bits on things". Very easy and straightforward to explain and understand.