Subject: Re: bug#14152: [PATCH] build: use 'chmod a-w' instead of 'chmod -w'

From: Enrico Scholz <[email-masked]>
Date: Sun, 07 Apr 2013 11:59:52 +0200

Pádraig Brady <[email-masked]> writes:

>>> What system does the build fail on as a matter of interest.
>> 
>> This will occur on any system that has umask set to 022.  Here is an example:
>> 
>>   $ umask 022
>>   $ touch foo
>>   $ chmod ug+w foo
>>   $ chmod -w foo
>>   chmod: foo: new permissions are r--rw-r--, not r--r--r--
>>   $ echo $?
>>   1
>
> But if the umask is 022, then those write bits shouldn't be set anyway?

These bits can be set due to various reasons; e.g.

$ mkdir /tmp/foo
$ setfacl -m d:m:rwx /tmp/foo

$ umask 022
$ touch /tmp/foo/x
$ chmod -w /tmp/foo/x
chmod: /tmp/foo/x: new permissions are r--rw-r--, not r--r--r--

I use such a setup (posix defaults acls) to build foreign software as a
special user while allowing working on the software (--> editing) as the
normal user.

Enrico