Re: Generated patches change over time

[Mark H Weaver]

address@hidden (Ludovic Courtès) writes:

> Maxim Cournoyer <address@hidden> skribis:
>
>>>> address@hidden (Ludovic Courtès) writes:
>>
>>>Lesson learned: we should not rely at all on generated patches because
>>>they are bound to change frequently (version string at the end, length
>>>of commit hash prefixes, etc.)  It’s probably worse than tarballs
>>>generated by Git hosting services.
>>>
>>>So we should probably work towards using local copies of patches,
>>>unless
>>>we find that the generated patches do not include any variable bits.
>>>
>>
>> Maybe we could pass the patches through some sanitizer to strip any 
>> metadata? I guess the content itself shouldn't change?
>
> We can’t really do that, or the downloads would no longer be
> fixed-output derivations and thus we wouldn’t be solving the problem.

Can you elaborate on why it cannot be done?  If I understand correctly,
our 'git-fetch' origin type deletes the .git subdirectory after fetching
it, and yet it still creates fixed-output derivations, no?  I don't see
why stripping metadata from a patch is fundamentally any different.

       Mark