AW: version headers

["Zimoch Dirk \(PSI\) via Core-talk" <core-talk at aps.anl.gov>]

Thank you, that really helped. I did not know that git could do those substitutions. (and that gitgub uses git archive to create the zip files)

Dirk

> -----Ursprüngliche Nachricht-----
> Von: Michael Davidsaver <mdavidsaver at gmail.com>
> Gesendet: Dienstag, 30. Juni 2020 18:07
> An: Zimoch Dirk (PSI) <dirk.zimoch at psi.ch>
> Cc: core-talk at aps.anl.gov
> Betreff: Re: version headers
> 
> I clicked send too soon.  More below.
> 
> On 6/30/20 7:26 AM, Zimoch Dirk (PSI) via Core-talk wrote:
> > Hi folks,
> >
> > I have a technical git related question. For StreamDevice, I used to update a
> version header file manually, but I always
> > forgot to update the numbers when tagging a release. How can I do this
> automatically? Git has hooks, but none for tag as
> > it seems (which would be also too late to be included in the tagged commit).
> >
> > The internet says: "No problem, simply generate the header (e.g. from 'git
> describe') when building your code." No
> > problem indeed as long as I have the git repo. But those users that download
> zip files from github instead of cloning
> > the repo complain now, as 'git describe' does not work for them, of course.
> >
> > Is there a way to generate the version header (or any other file that contains
> the related tag) on github when pushing
> > the release, so it is included when downloading a release zip file?
> 
> I don't have a great answer to this.  I'm not sure there is one.
> The best I know of is the git substitutions mechanism.
> 
> eg. from README in Base
> 
> > $Format:%cD$
> > $Format:%H$
> 
> https://github.com/epics-base/epics-
> base/blob/32ff3b2ed99bc27b9f5f876f2a9a48a29c40f2fe/README#L25-L26
> 
> and with substitution enabled
> 
> https://github.com/epics-base/epics-
> base/blob/32ff3b2ed99bc27b9f5f876f2a9a48a29c40f2fe/.gitattributes#L5
> 
> "git export" produces a README containing eg.
> 
> > Mon, 29 Jun 2020 21:20:05 -0700
> > e4e541e55e5f22d45ac4dff787f3a22b30d43b09
> 
> The various format strings are described by 'man git-log'.
> 
> https://git-scm.com/docs/git-log
> 
> So you might in your Makefile have something like
> 
> GENVERSIONDEFAULT=$Format:%d$
> 
> 
> Though I'm bound to say that I've not bother with this.
> My strategy these days is to reduce the number of places
> where I have to change a version number.  Preferably to one.
> 
> This is done in Base, and eg. by a module
> 
> https://github.com/mdavidsaver/pvxs/blob/master/configure/CONFIG_PVXS_V
> ERSION
> 
> I actually combine the two of these approaches so that the
> manually created version number is accessible to user modules
> both as make variables, and C macros.  The VCS revision is also
> captured, but only to be printed in various places.
> 
> https://github.com/mdavidsaver/pvxs/blob/651d7d18fbece66f158477761e58f7
> d5ca915933/src/Makefile#L37-L44