Based on a patch by Nikita Karetnikov <nikita@karetnikov.org>.
* guix-package.in (profile-regexp): New procedure.
(latest-profile-number): Remove `%profile-rx', and use
`profile-regexp' instead.
(profile-number, roll-back): New procedure.
(show-help): Add `--roll-back'.
(%options): Likewise.
(guix-package)[process-actions]: First check whether `roll-back?' is
among OPTS, and call `roll-back' if it is, followed by a recursive
call to `process-actions'. Emit the "nothing to be done" message only
when INSTALL or REMOVE is non-empty.
* tests/guix-package.sh (readlink_base): New function.
Add tests for `--roll-back'.
* doc/guix.texi (Invoking guix-package): Document `--roll-back'.
Reported by Andreas Enge.
* guix-package.in (%profile-directory): Honor $NIX_STATE_DIR.
(guix-package)[ensure-default-profile]: Use it.
[process-actions]: Call it when the `profile' option is
%CURRENT-PROFILE.
* tests/guix-package.sh: Add installation test with $HOME set, using the
default profile.
* guix-package.in (%options): Remove #\b as an alternate for
"bootstrap".
(show-help): Adjust accordingly.
* tests/guix-package.sh: Use `--bootstrap' instead of `-b'.
* tests/builders.scm (network-reachable?): New variable.
("url-fetch", "gnu-build"): Skip unless NETWORK-REACHABLE?.
* tests/derivations.scm (%coreutils): Check for network access.
("build-expression->derivation with one input"): Skip when %COREUTILS
is #f.
* tests/guix-package.sh: Skip installation of GNU Make when the network
is unreachable.
* tests/packages.scm ("GNU Make, bootstrap"): Likewise.
* tests/union.scm ("union-build"): Likewise.
* guix-package.in (guix-package)[process-actions]: Compute PACKAGES such
that packages listed in INSTALL* are first removed from the remainder
of the list. When PROF is equal to the previous profile's store path,
do nothing. Reported by Andreas Enge <andreas@enge.fr>.
* tests/guix-package.sh: Test the behavior of installing the same store
path twice. When removing a package, omit its version number.
* guix-package.in (guix-package)[find-package]: Return the correct NAME
and SUB-DRV when NAME contains #\:.
* tests/guix-package.sh (profile): Add test.
