guix package: 'guix package -r PKG -u' does not upgrade PKG.

Fixes <http://bugs.gnu.org/27262>.
Reported by Mark H Weaver <mhw@netris.org>.

* guix/scripts/package.scm (transaction-upgrade-entry): Check if ENTRY
matches 'manifest-transaction-removal-candidate?' and return TRANSACTION
if it does.
(process-actions): Move 'options->removable' from step 2 to step 1.

guix package: Warn about packages that no longer exist.

Fixes <http://bugs.gnu.org/27261>.
Reported by Mark H Weaver <mhw@netris.org>.

* guix/scripts/package.scm (transaction-upgrade-entry): Add call to
'warning' when NAME cannot be found in the package set.

refresh: Be more verbose when passed an explicit package list.

* guix/scripts/refresh.scm (check-for-package-update): Use
'version-compare' instead of 'version>?'.  When WARN? is true, print
something for the '=' and '<' cases.

environment: Disable profile collision checks.

Reported by Efraim Flashner.
This is a followup to a654dc4bcf7c8e205bdefa1a1d5f23444dd22778.

* guix/profiles.scm (profile-derivation): Add #:allow-collisions? and
honor it.
* guix/scripts/environment.scm (inputs->profile-derivation): Pass
 #:allow-collisions? #f to 'profile-derivation'.
* tests/guix-environment.sh: Test "guix environment guix".

guix package: '--search-paths' shows search paths from propagated inputs.

* guix/scripts/package.scm (process-query) <'search-paths>: Use
'manifest-transitive-entries' instead of 'manifest-entries'.

guix package: Always upgrade packages that have propagated inputs.

* guix/scripts/package.scm (transaction-upgrade-entry): Always upgrade
packages that have propagated inputs.

guix: Add texlive importer.

* guix/import/texlive.scm: New file.
* guix/scripts/import/texlive.scm: New file.
* Makefile.am (MODULES): Add them.
* tests/texlive.scm: New file.
* Makefile.am (SCM_TESTS): Add it.
* guix/scripts/import.scm (importers): Add texlive importer.
* doc/guix.texi (Invoking guix import): Document it.

guix package: '--search' sorts by relevance.

* guix/scripts/package.scm (find-packages-by-description): Rewrite to
compute a score based on the number of regexps matched and the number of
matches for each regexp.  Sort according to this score and return it as
a second value.
(process-query) <'search>: Capture the two return values of
'find-packages-by-description'.  Pass #:extra-fields to
'package->recutils'.
* doc/guix.texi (Invoking guix package): Mention relevance, give an
example.

derivations: Introduce 'read-derivation-from-file'.

This avoids the open/fstat/close syscalls upon a cache hit that we had
with the previous idiom:

  (call-with-input-file file read-derivation)

where caching happened in 'read-derivation' itself.

* guix/derivations.scm (%read-derivation): Rename to...
(read-derivation): ... this.
(read-derivation-from-file): New procedure.
(derivation-prerequisites, substitution-oracle)
(derivation-prerequisites-to-build):
(derivation-path->output-path, derivation-path->output-paths):
(derivation-path->base16-hash, map-derivation): Use
'read-derivation-from-file' instead of (call-with-input-file …
read-derivation).
* guix/grafts.scm (item->deriver): Likewise.
* guix/scripts/build.scm (log-url, options->things-to-build): Likewise.
* guix/scripts/graph.scm (file->derivation): Remove.
(derivation-dependencies, %derivation-node-type): Use
'read-derivation-from-file' instead.
* guix/scripts/offload.scm (guix-offload): Likewise.
* guix/scripts/perform-download.scm (guix-perform-download): Likewise.
* guix/scripts/publish.scm (load-derivation): Remove.
(narinfo-string): Use 'read-derivation-from-file'.

bootloader: Rename boot-name to bootloader-name.

* gnu/system (<boot-parameters>)[boot-name]: Rename field to...
[bootloader-name]: ... this.  Adjust users.
* gnu/scripts/system.scm: Adjust accordingly.

scripts: refresh: Add -m manifest option.

* guix/scripts/refresh.scm (%options): Add -m option,
(show-help): document it,
(packages-from-manifest): new procedure,
(guix-refresh): use packages from manifest if specified, otherwise
keep the previous behaviour.
* doc/guix.texi (Invoking guix refresh): document new option.

substitute: Do not display the installed size.

* guix/scripts/substitute.scm (process-substitution): Do not show the
installed size in the "Downloading" message.

syscalls: Provide 'free-disk-space'.

* guix/build/syscalls.scm (free-disk-space): New procedure.
* guix/scripts/gc.scm (guix-gc)[ensure-free-space]: Use it instead of
'statfs'.

Merge branch 'master' into staging

scripts: Set thread names.

This allows 'guix publish' threads as well as 'guix substitute' and
'guix offload' processes to be properly labeled in 'top', 'pstree', etc.

* guix/workers.scm (worker-thunk): Add #:thread-name parameter and honor it.
(make-pool): Likewise.
* guix/scripts/publish.scm (http-write): Add calls to 'set-thread-name'
in bodies of 'call-with-new-thread'.
(guix-publish): Call 'set-thread-name'.   Pass #:thread-name to 'make-pool'.
* guix/scripts/offload.scm (guix-offload): Call 'set-thread-name'.
* guix/scripts/substitute.scm (guix-substitute): Likewise.

Merge branch 'master' into staging

publish: Do not bake the same item several times.

Before this patch, there was a possibility that we'd queue several
baking tasks for the same item.  The first one would bake the item but
subsequent tasks wouldn't check whether the item had been baked in the
meantime and would re-bake it.

* guix/scripts/publish.scm (render-narinfo/cached): Don't call
'bake-narinfo+nar' when (file-exists? cached).

guix package: Swallow EPIPE upon 'guix package --list-generations'.

Fixes <http://bugs.gnu.org/27017>.
Reported by Alex Vong <alexvong1995@gmail.com>.

* guix/scripts/package.scm (process-query) <'list-generations>: Wrap
body in 'leave-on-EPIPE'.

guix: lint: Slightly simplify `check-source-file-name'.

* guix/scripts/lint.scm (check-source-file-name): Implement file name matching
  with regular expression.

gnu: lint: Fix typo.

* guix/scripts/lint.scm (check-source-file-name): Fix wrong return value in
  docstring.