mtree violations should be debug info, should not be fatal errors

[Weissmann Markus]

On 12 Aug 2007, at 07:25, markd at macports.org wrote:

> Ryan Schmidt <ryandesign at macports.org> writes:
>> I'm not sure I like that mtree violations are fatal errors. The ports
>> that are now failing to install because of mtree violations installed
>> just fine in MacPorts 1.5.0. Why should they now fail to install?
>> Their content has not changed. Sure, they may be installing things in
>> places they shouldn't, but why should we make the user suffer? We
>> have a -t switch which informs us about forgotten dependencies in the
>> port -- but this does not issue a fatal error. It's just a message
>> which portfile authors can use to improve their portfiles. Maybe
>> mtree violations could be handled similarly.
>>
>> I'm also concerned about needing to specify in the portfile that the
>> port intends to violate the mtree. For example, I'm going to have to
>> add that to the php5 port, because it wants to install an apache2
>> module and the apache2 layout is considered nonstandard. So just
>> because I want to install one item in a weird place, I have to turn
>> off the mtree violation checks in the entire php5 portfile. It would
>> be nicer if port would just issue nonfatal debug messages letting us
>> know exactly which files were violating the mtree. This way I could
>> assure myself that my port is installing the apache2 module in a
>> weird place, yes, but that everything else is being installed in sane
>> locations.
>
> +1  And I still don't know exactly what an mtree violation is.
>

we've documented the should-be state of the layout of the ports- 
filesystems years ago already - see porthier(7); if ports fail  
because of this right now, it is most likely either because our  
implementation is faulty or the port is buggy.

The deal is, that port(1) should really protect a user from having  
files installed "somewhere", e.g. in /System; if a port really has to  
install files in a non-standard location, it should indicate this.  
Installing files e.g. in /usr can be fatal for a system and can  
render it unusable. A port might overwrite system files, install some  
kernel extension, etc.
I do not see a reason to not protect a user from an accident like  
this. (The trace mode will not protect you here, it keeps ports from  
writing to wrong locations before the install phase.)

For the rare occasion that it is necessary to install e.g. a kext, an  
indication by the port author is not a big deal. I assume that only a  
few ports require this right now while we might find some dozen ports  
which are just buggy and no one noticed so far.

There is a bug in the current implementation that incorrectly  
complains about files in e.g. "/Applications" which has been fixed in  
trunk already. (but is in 1.5.1!)


-Markus

---
Markus W. Weissmann
http://www.mweissmann.de/