Depending on and generating files in system definitions

[Jan Moringen]

(replying to myself as I'm not subscribed to the ml and thus didn't get
Robert's email, sorry).

Thank you for the quick reply, Robert.

> I only had time for a quick look at this, but it did suggest a couple
> of questions:
> 
> 1. Is it necessary to have rsb-version write the version-string.sexp
> file?  Could you simply override the COMPONENT-VERSION generic
> function and compute it on the fly from git and version.sexpr?

I omitted the fact that version.sexp can also contain the complete
version specification in which case rsb-version writes version-
string.sexp without consulting git. This mode is intended for
installing or packaging the sources independently of the git
repository.

One use case for this ability is packaging the source with cached
version information and copying it into the workspace of a different
project in a continuous integration scenario. 

Also, shelling out to git for each COMPONENT-VERSION method call seems
expensive to me (But maybe I'm just paranoid since my previous solution
was super inefficient and wasteful).

> 2. How does this work across developers?  Couldn't you end up in a
> situation where two developers have versions x.y.z and x.y.z' where z
> = z' but the two systems are different (because they are on different
> git repositories with differing histories)?  In an ideal world, the
> version identifier should identify a unique state of the codebase,
> yes?
> 
> I suppose one could get the version identifier from some shared
> history (like the remotes/origin branch).

The requirement here is mostly that non-lisp-developers (or even non-
developers) can build (and pull + re-build) the master branch and
release branches of the project and automatically get a binary with
detailed and accurate version information.

I guess rsb-version could also writes a version-details.sexp which
would include the commit id. But I cannot see how that would work as an
ASDF system version (I seem to recall that net.didierverna.clon has
something like that and ASDF seems to get upset about it).

> 3. Your rsb-protocol-config system seems quite reasonable.  We have
> done things like this to, for example, invoke "make" to build
> required non-lisp code.

Good, thanks.

Again, thanks for the quick reply and valuable feedback.

Kind regards,
Jan