Re: [PATCH 4/4] Add 'filter' attribute and external filter driver definition.

From: David Lang <david.lang@digitalinsight.com>
Date: Apr 22, 2007, 09:20 UTC
Message-ID: <Pine.LNX.4.63.0704220215540.5946@qynat.qvtvafvgr.pbz>
In-Reply-To: <Pine.LNX.4.63.0704220202550.5946@qynat.qvtvafvgr.pbz>

On Sun, 22 Apr 2007, David Lang wrote:

Show 20 quoted lines

> On Sat, 21 Apr 2007, Junio C Hamano wrote:
>
>> David Lang <david.lang@digitalinsight.com> writes:
>> 
>>> 1. it would be useful in many cases for the filter program to know
>>> what file it's working on (and probably some other things), so there
>>> are probably some command-line arguments that should be able to be
>>> passed to the filter.
>> 
>> I can see that you missed the class when Linus talked about how
>> messy things would get once you allow the conversion to be
>> stateful.  I was in the class and remembered it ;-)
>> 
>> Although I initially considered interpolating "%P" with
>> pathname, I ended up deciding against it, to discourage people
>> from abusing the filter for stateful conversion that changes the
>> results depending on time, pathname, commit, branch and stuff.
>
> I didn't miss it, I just don't think that the path in the repository is 
> nessasarily as dangerous as the other things (time, branch, etc)

to clarify a bit more. I have a perl program that I can point at the 'interesting' files on my systems and have it create a 'generic' version of that file. I can then take that generic version of the file to any machine in the cluster and with the same program create a version of that generic file that's correct for the other system. however to know which substatutions are appropriate to do for the file, it needs to know the filename (well, I guess I could create a whole bunch of seperate config files, and then define all the files with different filters, each filter including the config file to use fo rthat specific file, but this seems like a really ugly way to do it)

> one thing that was listed as a possibilty was to use the sha1 of the file, 
> but you would force the filter to calculate that itself. it's already 
> available when extracting and recalcuating it is a waste

ignore this comment, I see you posted an example of this.

David Lang