[Openmcl-devel] moving Clozure CL to GitHub

R. Matthew Emerson rme at acm.org
Fri Feb 10 07:22:44 PST 2017

> On Feb 9, 2017, at 10:48 PM, Ron Garret <ron at flownet.com> wrote:
> On Feb 9, 2017, at 7:39 PM, R. Matthew Emerson <rme at acm.org> wrote:
>> I still have not come up with a brilliant idea to solve the problem of distributing bootstrapping images and interface databases for each of the supported platforms.
> Can you explain why this is any more of a problem with git than it was with subversion?

Back when OpenMCL was still in CVS, the way to get a copy was a multi-step process.

1. get sources (via checkout or via downloading a file, e.g., openmcl-src-0.12.tar.gz)

2. get interface databases (so that stuff like (#_getpid) will work) by downloading, e.g., openmcl-interfaces-0.4.tar.gz

3. get bootstrapping image (e.g., openmcl-darwinppc-bin-0.12.tar.gz) in order to have a lisp to compile the sources

When we switched to Subversion, we were able to do two things:

1. Check in interface databases and bootstrapping binaries

2. (Ab-)use externals so that it is possible to get sources, interface databases, and bootstrapping binaries in a single command

Subversion supports binaries fairly well: it can diff them and store deltas.  Since it's a centralized system, it doesn't matter if the repository gets large, because checking out a working copy doesn't have to copy the whole repository.

Git is less suited to storing binaries.  It stores them whole (i.e., it doesn't diff them), and since cloning a git repository copies the entire repository, bloating the repository with binaries is a real concern.

In summary, I think that having a one-command way to get a working CCL is a good feature.  I have never liked the way we abuse externals to do that, but the get-ccl-with-one-command feature seemed valuable enough that it was worth it anyway.

Ideally, I'd like to make it equally easy to get a working CCL when we're on GitHub.   That's what I'm trying to figure out how to do.  It may be that I can preserve a one-step way to get CCL.  Or it might be necessary to a) get source and then b) get interfaces & bootstrapping image.  I'm hopeful that GitHub releases will be a good enough tool for this.

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