bug#51609: version.texi UPDATED field does not account for timezone; can cause unnecessary documentation rebuilds, which could fail

[Ryan Schmidt]

Thanks Karl, that must be the same problem. Apologies for not finding that in 
my searches prior to filing this bug.

gdbm 1.22 ships with mdate-sh "scriptversion=2010-08-21.06; # UTC" so it must 
not yet include this fix. Looks like their makefiles are generated with 
automake 1.15. I'll file a bug report with gdbm asking them to regenerate with 
automake 1.16 or later.


> On Nov 6, 2021, at 16:10, Karl Berry <karl@freefriends.org> wrote:
> 
> Hi Ryan - thanks for the report. In Automake, those version.texi
> variables are updated by the auxiliary script mdate-sh. In Automake
> 1.16, it seems mdate-sh was changed to compute the dates using UTC
> (ChangeLog entry below, describing exactly what you saw, it seems),
> with these lines:
> 
>    # Use UTC to get reproducible result.
>    TZ=UTC0
>    export TZ
> 
> You can get the latest mdate-sh from automake or gnulib and just put it
> in place independent of any other updates.
> 
> If you already have the latest mdate-sh, then I'd appreciate seeing a
> recipe to reproduce, hopefully with smaller than gdbm itself
> .. --thanks, karl.
> 
> 
> 2017-09-15  Reiner Herrmann  <reiner@reiner-h.de>  (tiny change)
> 
>       mdate-sh: Ensure reproducible time output
> 
>       This change fixes automake bug#20314.
>       [ https://debbugs.gnu.org/cgi/bugreport.cgi?bug=20314 ]
> 
>       'mdate-sh' pretty-prints the modification time of a file.  But it's
>       output can vary depending on the timezone of the caller. Someone in
>       timezone GMT-12 will get a different result (day) than someone in
>       timezone GMT+12.  As this output is also used to create/update stamp
>       files, which influence the further build process, the build result can
>       vary.
> 
>       * lib/mdate-sh: Set 'TZ' to UTC which ensures reproducible output.
>       * NEWS: Announce bug fix.
> 
>