Generated patches change over time

[Ludovic Courtès]

Hello Mark,

Mark H Weaver <address@hidden> skribis:

> address@hidden (Ludovic Courtès) writes:
>
>> address@hidden skribis:
>>
>>> commit e1d97c4efc42a661bd2772041371303e4070aa4f
>>> Author: Mark H Weaver <address@hidden>
>>> Date:   Mon Nov 5 04:04:45 2018 -0500
>>>
>>>     gnu: rhythmbox: Update hash of patch.
>>>     
>>>     * gnu/packages/gnome.scm (rhythmbox)[source]: Update hash of the applied
>>>     patch.

[...]

>> Could you explain the difference between the two patches?
>>
>> In general I think we should keep providing detailed explanations in the
>> commit log (and possibly in the bug tracker) when such problems occur.
>
> Agreed.  Thanks for paying attention to these things :)
>
> At the time that I first committed this patch to my private branch,
> Hydra was offline, and it wasn't obvious to me how to get the old
> version.  However, I could see that the patch was so trivial that I
> didn't worry about it.  Still, I probably should have asked on the
> mailing list.

Indeed, that’s reasonable.  :-)

> Anyway, see below for the diff between the old patch and the new one.
>
>       Thanks,
>         Mark
>
> --- t.patch   2018-11-25 16:26:38.946968736 -0500
> +++ b182c6b9e1d09e601bac0b703cc5f8b159ebbc3a.patch    2018-11-25 
> 14:53:32.019264658 -0500
> @@ -19,7 +19,7 @@
>   1 file changed, 1 insertion(+), 1 deletion(-)
>  
>  diff --git a/plugins/fmradio/rb-fm-radio-gst-src.c 
> b/plugins/fmradio/rb-fm-radio-gst-src.c
> -index 09d709c..88abdaf 100644
> +index 09d709c28..88abdaf35 100644
>  --- a/plugins/fmradio/rb-fm-radio-gst-src.c
>  +++ b/plugins/fmradio/rb-fm-radio-gst-src.c
>  @@ -178,7 +178,7 @@ plugin_init (GstPlugin *plugin)
> @@ -31,6 +31,6 @@
>                  "element to output silence",
>                  plugin_init,
>                  VERSION,
> ---
> -libgit2 0.27.1
> +-- 
> +2.18.1

Thanks for checking.

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.

Currently packages that include downloaded patches are¹:

  ("address@hidden"
   "address@hidden"
   "address@hidden"
   "address@hidden"
   "address@hidden"
   "address@hidden"
   "address@hidden"
   "address@hidden"
   "address@hidden"
   "address@hidden"
   "address@hidden"
   "address@hidden"
   "address@hidden"
   "address@hidden"
   "address@hidden"
   "address@hidden"
   "address@hidden"
   "address@hidden"
   "address@hidden"
   "address@hidden"
   "address@hidden"
   "address@hidden"
   "address@hidden"
   "address@hidden"
   "address@hidden"
   "address@hidden")

In the case of bash and texlive, the patches are not generated so we’re
fine.  That of vlc at
<https://git.videolan.org/?p=vlc.git;a=patch;h=a8953ba707cca1f2de372ca24513296bcfcdaaa8>
is generated though.

Needs more investigation!

Thanks,
Ludo’.

¹ I used:
   (fold-packages (lambda (p r)
                    (let ((source (package-source p)))
                      (if (origin? source)
                          (let ((patches (origin-patches source)))
                            (if (any origin? patches)
                                (cons p r)
                                r))
                          r)))
                  '())