* guix/describe.scm (append-channels-to-load-path!): New function.
* gnu/packages.scm (%package-module-path): Call new function. Remove
the code that the function call replaces.
* guix/ui.scm (extension-directories): Call new function. Search
channels for guix extensions.
* guix/self.scm (compiled-guix)[*core-modules*]: Add 'guile-git' to
the list of extensions.

Change-Id: I53af828dc554485ca28389c9e2653ea6b4fb6b7e
Signed-off-by: Ludovic Courtès <ludo@gnu.org>

On my laptop, wall-clock time for (all-packages) goes from 27s to 1s.

* gnu/packages.scm (all-packages): Use a hash table to remember visited
packages instead of calling ‘delete-duplicates’ on the final list.

Change-Id: I4aae804656b56ef2095993e91f0572a5891f419f

* gnu/packages.scm (all-packages): New procedure.
* etc/source-manifest.scm (all-packages): Remove.
* guix/scripts/graph.scm (all-packages): Remove.
* guix/scripts/refresh.scm (all-packages): Remove.
* guix/scripts/weather.scm (all-packages): Remove.

Change-Id: I6072952c4b877b541037ce86402cfb7744eeb0a0

* gnu/packages.scm (generate-package-cache): Adjust for Guile 3.0.9.

* gnu/packages.scm (%package-module-path): Use 'let*' instead of
'let*-values'.
(specification->package, specification->location)
(specification->package+output): Use 'let' instead of 'let-values'.

* gnu/packages.scm (specifications->packages): New procedure.
* guix/scripts/home/import.scm (manifest+configuration-files->code): Use it.
* tests/home-import.scm (match-home-environment-no-services)
(match-home-environment-no-services-nor-packages)
(match-home-environment-bash-service)
(match-home-environment-bash-service-with-alias): Adjust 'packages'
field accordingly.

Co-authored-by: Ludovic Courtès <ludo@gnu.org>

* gnu/packages.scm (package-unique-version-prefix): New procedure.
* guix/scripts/package.scm (manifest-entry-version-prefix): Use it.
* tests/packages.scm ("package-unique-version-prefix, gcc@8")
("package-unique-version-prefix, grep"): New tests.

This enables profile caching not just when '-m' or '-f' is used, but
also when package specs are passed on the command line, as in:

  guix shell -D guix git

It also changes profile cache keys to include the system type, which was
previously ignored.

* guix/scripts/shell.scm (options-with-caching)[single-file-for-caching]:
Remove.
Call 'profile-cached-gc-root' instead; adjust to accept two values.
(profile-cache-primary-key): New procedure.
(profile-cache-key): Remove.
(profile-file-cache-key, profile-spec-cache-key): New procedures.
(profile-cached-gc-root): Rewrite to include functionality formally in
'single-file-for-caching', but extend to handle package specs.
* gnu/packages.scm (cache-is-authoritative?): Export.
* guix/transformations.scm (transformation-option-key?): New procedure.
* doc/guix.texi (Invoking guix shell): Move '--rebuild-cache'
documentation to the bottom, just above '--root'.  Explain caching and
how these two options relate to that.

Fixes <https://bugs.gnu.org/42009>.
Reported by Marinus <marinus.savoritias@disroot.org>.

* gnu/packages.scm (generate-package-cache)[entry-key, entry<?]
[variables]: New variables.
[expand-cache]: Change to take two arguments.
[exp]: Fold over VARIABLES.

* gnu.scm (%try-use-modules): Use 'formatted-message' instead of
'&message'.
* gnu/machine/digital-ocean.scm (maybe-raise-unsupported-configuration-error):
Likewise.
* gnu/machine/ssh.scm (machine-check-file-system-availability): Likewise.
(machine-check-building-for-appropriate-system): Likewise.
(deploy-managed-host): Likewise.
(maybe-raise-unsupported-configuration-error): Likewise.
* gnu/packages.scm (search-patch): Likewise.
* gnu/services.scm (%service-with-default-value): Likewise.
(files->etc-directory): Likewise.
(fold-services): Likewise.
* gnu/system.scm (locale-name->definition*): Likewise.
* gnu/system/mapped-devices.scm (check-device-initrd-modules): Likewise.
(check-luks-device): Likewise.
* guix/channels.scm (latest-channel-instance): Likewise.
* guix/cve.scm (json->cve-items): Likewise.
* guix/git-authenticate.scm (commit-signing-key): Likewise.
(commit-authorized-keys): Likewise.
(authenticate-commit): Likewise.
(verify-introductory-commit): Likewise.
* guix/remote.scm (remote-pipe-for-gexp): Likewise.
* guix/scripts/graph.scm (assert-package): Likewise.
* guix/scripts/offload.scm (private-key-from-file*): Likewise.
* guix/ssh.scm (authenticate-server*): Likewise.
(open-ssh-session): Likewise.
(remote-inferior): Likewise.
* guix/ui.scm (matching-generations): Likewise.
* guix/upstream.scm (package-update): Likewise.
* tests/channels.scm ("latest-channel-instances, missing introduction for 'guix'"):
Catch 'formatted-message?'.
("authenticate-channel, wrong first commit signer"): Likewise.
* tests/lint.scm ("patches: not found"): Adjust message string.
* tests/packages.scm ("patch not found yields a run-time error"): Catch
'formatted-message?'.
* guix/lint.scm (check-patch-file-names): Handle 'formatted-message?'.
(check-derivation): Ditto.