Last modification date of the document with git?

[Vivien Kraus]

Dear texinfo hackers,

I’m currently developing my own package with git, and build it with GNU
Guix.

Both git and guix won’t care about the modification dates of my files.
Git will override it when I check out some commit, and git clone won’t
preserve the modification date. Guix will even reset it to Jan 1st
1970, because random dates may harm reproducibility if they depend on
the current date.

Since I use automake, the file last modification date is unfortunately
the date used to indicate the last modification of the document. So, it
is very imprecise to use, and won’t survive a git clone.

However, git can tell me what commit modified the document, and from
that I can take the (author, or maybe commit?) date. It should be a way
better approximation of the true date of last modification.

There are two problems with this approach: if the git clone used to
build the project is shallow (this is the case with Guix, for
instance), I won’t be able to get a useful git log. Also, it’s quite
hard to change the way Automake computes the modification date (I could
do without the version.texi automake trick though).

I imagine a lot of texinfo users actually use git. Actually, texinfo
devs *themselves* use git to maintain a texinfo document (the texinfo
manual). I see from the texinfo source that they use the version.texi
Automake trick, and I expect others to do so too. How do you tackle
this issue? Do you just hope nothing "touches" your texi files on your
hard drive?

Vivien