Re: Multiple versions

[Ludovic Courtès]

Dmitry Bogatov <address@hidden> skribis:

> Currently, I am at master branch. I want install parallel-20151122.
> But it is gone since 0877e. I propose to keep *all* versions,
> but just 'parallel' refer to latest.

First, I think it’s important to distinguish the source (the package
recipes in gnu/packages/*.scm) and the installed packages (stuff in
/gnu/store.)

Users can keep the versions they want in their store and in their
profiles.

For recipes, as Andreas noted, it would be terrible for Guix as a
project to provide and maintain zillions of different versions of each
package (keeping them all would be easy, but we want to provide packages
that actually build :-)).

However, users can write their own modules containing different versions
or variants of the packages.  For instance, you could write:

  (define-module (my-packages)
    #:use-module (gnu packages parallel))

  (define my-parallel
    ;; Inherit from the Parallel recipe that Guix provides, but override
    ;; the version being used.
    (package
      (inherit parallel)
      (version "x.y.z")
      (source (origin
                (method url-fetch)
                (uri (string-append "mirror://gnu/parallel/parallel-"
                                    version ".tar.bz2"))
                (sha256
                 (base32
                  "0phn9dlkqlq3cq468ypxbbn78bsjcin743pyvf8ip4qg6jz662jm"))))))

Then drop that in ‘GUIX_PACKAGE_PATH’, and run:

  guix package -i parallel-x.y.z

HTH,
Ludo’.