guix/channels.scm

   1 ;;; GNU Guix --- Functional package management for GNU
   2 ;;; Copyright © 2018, 2019 Ludovic Courtès <ludo@gnu.org>
   3 ;;; Copyright © 2018 Ricardo Wurmus <rekado@elephly.net>
   4 ;;; Copyright © 2019 Jan (janneke) Nieuwenhuizen <janneke@gnu.org>
   5 ;;;
   6 ;;; This file is part of GNU Guix.
   7 ;;;
   8 ;;; GNU Guix is free software; you can redistribute it and/or modify it
   9 ;;; under the terms of the GNU General Public License as published by
  10 ;;; the Free Software Foundation; either version 3 of the License, or (at
  11 ;;; your option) any later version.
  12 ;;;
  13 ;;; GNU Guix is distributed in the hope that it will be useful, but
  14 ;;; WITHOUT ANY WARRANTY; without even the implied warranty of
  15 ;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16 ;;; GNU General Public License for more details.
  17 ;;;
  18 ;;; You should have received a copy of the GNU General Public License
  19 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
  20
  21 (define-module (guix channels)
  22   #:use-module (git)
  23   #:use-module (guix git)
  24   #:use-module (guix records)
  25   #:use-module (guix gexp)
  26   #:use-module (guix modules)
  27   #:use-module (guix discovery)
  28   #:use-module (guix monads)
  29   #:use-module (guix profiles)
  30   #:use-module (guix packages)
  31   #:use-module (guix derivations)
  32   #:use-module (guix combinators)
  33   #:use-module (guix diagnostics)
  34   #:use-module (guix sets)
  35   #:use-module (guix store)
  36   #:use-module (guix i18n)
  37   #:use-module ((guix utils)
  38                 #:select (source-properties->location
  39                           &error-location))
  40   #:use-module (srfi srfi-1)
  41   #:use-module (srfi srfi-2)
  42   #:use-module (srfi srfi-9)
  43   #:use-module (srfi srfi-11)
  44   #:use-module (srfi srfi-26)
  45   #:use-module (srfi srfi-34)
  46   #:use-module (srfi srfi-35)
  47   #:autoload   (guix self) (whole-package make-config.scm)
  48   #:autoload   (guix inferior) (gexp->derivation-in-inferior) ;FIXME: circular dep
  49   #:use-module (ice-9 match)
  50   #:use-module (ice-9 vlist)
  51   #:use-module ((ice-9 rdelim) #:select (read-string))
  52   #:export (channel
  53             channel?
  54             channel-name
  55             channel-url
  56             channel-branch
  57             channel-commit
  58             channel-location
  59
  60             %default-channels
  61             guix-channel?
  62
  63             channel-instance?
  64             channel-instance-channel
  65             channel-instance-commit
  66             channel-instance-checkout
  67
  68             latest-channel-instances
  69             checkout->channel-instance
  70             latest-channel-derivation
  71             channel-instances->manifest
  72             %channel-profile-hooks
  73             channel-instances->derivation
  74
  75             profile-channels
  76
  77             channel-news-entry?
  78             channel-news-entry-commit
  79             channel-news-entry-tag
  80             channel-news-entry-title
  81             channel-news-entry-body
  82
  83             channel-news-for-commit))
  84
  85 ;;; Commentary:
  86 ;;;
  87 ;;; This module implements "channels."  A channel is usually a source of
  88 ;;; package definitions.  There's a special channel, the 'guix' channel, that
  89 ;;; provides all of Guix, including its commands and its documentation.
  90 ;;; User-defined channels are expected to typically provide a bunch of .scm
  91 ;;; files meant to be added to the '%package-search-path'.
  92 ;;;
  93 ;;; This module provides tools to fetch and update channels from a Git
  94 ;;; repository and to build them.
  95 ;;;
  96 ;;; Code:
  97
  98 (define-record-type* <channel> channel make-channel
  99   channel?
 100   (name      channel-name)
 101   (url       channel-url)
 102   (branch    channel-branch (default "master"))
 103   (commit    channel-commit (default #f))
 104   (location  channel-location
 105              (default (current-source-location)) (innate)))
 106
 107 (define %default-channels
 108   ;; Default list of channels.
 109   (list (channel
 110          (name 'guix)
 111          (branch "master")
 112          (url "https://git.savannah.gnu.org/git/guix.git"))))
 113
 114 (define (guix-channel? channel)
 115   "Return true if CHANNEL is the 'guix' channel."
 116   (eq? 'guix (channel-name channel)))
 117
 118 (define-record-type <channel-instance>
 119   (channel-instance channel commit checkout)
 120   channel-instance?
 121   (channel   channel-instance-channel)
 122   (commit    channel-instance-commit)
 123   (checkout  channel-instance-checkout))
 124
 125 (define-record-type <channel-metadata>
 126   (channel-metadata directory dependencies news-file)
 127   channel-metadata?
 128   (directory     channel-metadata-directory)      ;string with leading slash
 129   (dependencies  channel-metadata-dependencies)   ;list of <channel>
 130   (news-file     channel-metadata-news-file))     ;string | #f
 131
 132 (define (channel-reference channel)
 133   "Return the \"reference\" for CHANNEL, an sexp suitable for
 134 'latest-repository-commit'."
 135   (match (channel-commit channel)
 136     (#f      `(branch . ,(channel-branch channel)))
 137     (commit  `(commit . ,(channel-commit channel)))))
 138
 139 (define (read-channel-metadata port)
 140   "Read from PORT channel metadata in the format expected for the
 141 '.guix-channel' file.  Return a <channel-metadata> record, or raise an error
 142 if valid metadata could not be read from PORT."
 143   (match (read port)
 144     (('channel ('version 0) properties ...)
 145      (let ((directory    (and=> (assoc-ref properties 'directory) first))
 146            (dependencies (or (assoc-ref properties 'dependencies) '()))
 147            (news-file    (and=> (assoc-ref properties 'news-file) first)))
 148        (channel-metadata
 149         (cond ((not directory) "/")               ;directory
 150               ((string-prefix? "/" directory) directory)
 151               (else (string-append "/" directory)))
 152         (map (lambda (item)                       ;dependencies
 153                (let ((get (lambda* (key #:optional default)
 154                             (or (and=> (assoc-ref item key) first) default))))
 155                  (and-let* ((name (get 'name))
 156                             (url (get 'url))
 157                             (branch (get 'branch "master")))
 158                    (channel
 159                     (name name)
 160                     (branch branch)
 161                     (url url)
 162                     (commit (get 'commit))))))
 163              dependencies)
 164         news-file)))                              ;news-file
 165     ((and ('channel ('version version) _ ...) sexp)
 166      (raise (condition
 167              (&message (message "unsupported '.guix-channel' version"))
 168              (&error-location
 169               (location (source-properties->location
 170                          (source-properties sexp)))))))
 171     (sexp
 172      (raise (condition
 173              (&message (message "invalid '.guix-channel' file"))
 174              (&error-location
 175               (location (source-properties->location
 176                          (source-properties sexp)))))))))
 177
 178 (define (read-channel-metadata-from-source source)
 179   "Return a channel-metadata record read from channel's SOURCE/.guix-channel
 180 description file, or return the default channel-metadata record if that file
 181 doesn't exist."
 182   (catch 'system-error
 183     (lambda ()
 184       (call-with-input-file (string-append source "/.guix-channel")
 185         read-channel-metadata))
 186     (lambda args
 187       (if (= ENOENT (system-error-errno args))
 188           (channel-metadata "/" '() #f)
 189           (apply throw args)))))
 190
 191 (define (channel-instance-metadata instance)
 192   "Return a channel-metadata record read from the channel INSTANCE's
 193 description file or its default value."
 194   (read-channel-metadata-from-source (channel-instance-checkout instance)))
 195
 196 (define (channel-instance-dependencies instance)
 197   "Return the list of channels that are declared as dependencies for the given
 198 channel INSTANCE."
 199   (channel-metadata-dependencies (channel-instance-metadata instance)))
 200
 201 (define* (latest-channel-instances store channels #:optional (previous-channels '()))
 202   "Return a list of channel instances corresponding to the latest checkouts of
 203 CHANNELS and the channels on which they depend.  PREVIOUS-CHANNELS is a list
 204 of previously processed channels."
 205   ;; Only process channels that are unique, or that are more specific than a
 206   ;; previous channel specification.
 207   (define (ignore? channel others)
 208     (member channel others
 209             (lambda (a b)
 210               (and (eq? (channel-name a) (channel-name b))
 211                    (or (channel-commit b)
 212                        (not (or (channel-commit a)
 213                                 (channel-commit b))))))))
 214
 215   ;; Accumulate a list of instances.  A list of processed channels is also
 216   ;; accumulated to decide on duplicate channel specifications.
 217   (define-values (resulting-channels instances)
 218     (fold2 (lambda (channel previous-channels instances)
 219              (if (ignore? channel previous-channels)
 220                  (values previous-channels instances)
 221                  (begin
 222                    (format (current-error-port)
 223                            (G_ "Updating channel '~a' from Git repository at '~a'...~%")
 224                            (channel-name channel)
 225                            (channel-url channel))
 226                    (let-values (((checkout commit)
 227                                  (latest-repository-commit store (channel-url channel)
 228                                                            #:ref (channel-reference
 229                                                                   channel))))
 230                      (let ((instance (channel-instance channel commit checkout)))
 231                        (let-values (((new-instances new-channels)
 232                                      (latest-channel-instances
 233                                       store
 234                                       (channel-instance-dependencies instance)
 235                                       previous-channels)))
 236                          (values (append (cons channel new-channels)
 237                                          previous-channels)
 238                                  (append (cons instance new-instances)
 239                                          instances))))))))
 240            previous-channels
 241            '()                                    ;instances
 242            channels))
 243
 244   (let ((instance-name (compose channel-name channel-instance-channel)))
 245     ;; Remove all earlier channel specifications if they are followed by a
 246     ;; more specific one.
 247     (values (delete-duplicates instances
 248                                (lambda (a b)
 249                                  (eq? (instance-name a) (instance-name b))))
 250             resulting-channels)))
 251
 252 (define* (checkout->channel-instance checkout
 253                                      #:key commit
 254                                      (url checkout) (name 'guix))
 255   "Return a channel instance for CHECKOUT, which is assumed to be a checkout
 256 of COMMIT at URL.  Use NAME as the channel name."
 257   (let* ((commit  (or commit (make-string 40 #\0)))
 258          (channel (channel (name name)
 259                            (commit commit)
 260                            (url url))))
 261     (channel-instance channel commit checkout)))
 262
 263 (define %self-build-file
 264   ;; The file containing code to build Guix.  This serves the same purpose as
 265   ;; a makefile, and, similarly, is intended to always keep this name.
 266   "build-aux/build-self.scm")
 267
 268 (define %pull-version
 269   ;; This is the version of the 'guix pull' protocol.  It specifies what's
 270   ;; expected from %SELF-BUILD-FILE.  The initial version ("0") was when we'd
 271   ;; place a set of compiled Guile modules in ~/.config/guix/latest.
 272   1)
 273
 274 (define (standard-module-derivation name source core dependencies)
 275   "Return a derivation that builds with CORE, a Guix instance, the Scheme
 276 modules in SOURCE and that depend on DEPENDENCIES, a list of lowerable
 277 objects.  The assumption is that SOURCE contains package modules to be added
 278 to '%package-module-path'."
 279
 280   (let* ((metadata (read-channel-metadata-from-source source))
 281          (directory (channel-metadata-directory metadata)))
 282
 283     (define build
 284       ;; This is code that we'll run in CORE, a Guix instance, with its own
 285       ;; modules and so on.  That way, we make sure these modules are built for
 286       ;; the right Guile version, with the right dependencies, and that they get
 287       ;; to see the right (gnu packages …) modules.
 288       (with-extensions dependencies
 289         #~(begin
 290             (use-modules (guix build compile)
 291                          (guix build utils)
 292                          (srfi srfi-26))
 293
 294             (define go
 295               (string-append #$output "/lib/guile/" (effective-version)
 296                              "/site-ccache"))
 297             (define scm
 298               (string-append #$output "/share/guile/site/"
 299                              (effective-version)))
 300
 301             (let* ((subdir #$directory)
 302                    (source (string-append #$source subdir)))
 303               (compile-files source go (find-files source "\\.scm$"))
 304               (mkdir-p (dirname scm))
 305               (symlink (string-append #$source subdir) scm))
 306
 307             scm)))
 308
 309     (gexp->derivation-in-inferior name build core)))
 310
 311 (define (syscalls-reexports-local-variables? source)
 312   "Return true if (guix build syscalls) contains the bug described at
 313 <https://bugs.gnu.org/36723>."
 314   (catch 'system-error
 315     (lambda ()
 316       (define content
 317         (call-with-input-file (string-append source
 318                                              "/guix/build/syscalls.scm")
 319           read-string))
 320
 321       ;; The faulty code would use the 're-export' macro, causing the
 322       ;; 'AT_SYMLINK_NOFOLLOW' local variable to be re-exported when using
 323       ;; Guile > 2.2.4.
 324       (string-contains content "(re-export variable)"))
 325     (lambda args
 326       (if (= ENOENT (system-error-errno args))
 327           #f
 328           (apply throw args)))))
 329
 330 (define (guile-2.2.4)
 331   (module-ref (resolve-interface '(gnu packages guile))
 332               'guile-2.2.4))
 333
 334 (define %quirks
 335   ;; List of predicate/package pairs.  This allows us provide information
 336   ;; about specific Guile versions that old Guix revisions might need to use
 337   ;; just to be able to build and run the trampoline in %SELF-BUILD-FILE.  See
 338   ;; <https://bugs.gnu.org/37506>
 339   `((,syscalls-reexports-local-variables? . ,guile-2.2.4)))
 340
 341 (define* (guile-for-source source #:optional (quirks %quirks))
 342   "Return the Guile package to use when building SOURCE or #f if the default
 343 '%guile-for-build' should be good enough."
 344   (let loop ((quirks quirks))
 345     (match quirks
 346       (()
 347        #f)
 348       (((predicate . guile) rest ...)
 349        (if (predicate source) (guile) (loop rest))))))
 350
 351 (define* (build-from-source name source
 352                             #:key core verbose? commit
 353                             (dependencies '()))
 354   "Return a derivation to build Guix from SOURCE, using the self-build script
 355 contained therein; use COMMIT as the version string.  When CORE is true, build
 356 package modules under SOURCE using CORE, an instance of Guix."
 357   ;; Running the self-build script makes it easier to update the build
 358   ;; procedure: the self-build script of the Guix-to-be-installed contains the
 359   ;; right dependencies, build procedure, etc., which the Guix-in-use may not
 360   ;; be know.
 361   (define script
 362     (string-append source "/" %self-build-file))
 363
 364   (if (file-exists? script)
 365       (let ((build (save-module-excursion
 366                     (lambda ()
 367                       ;; Disable deprecation warnings; it's OK for SCRIPT to
 368                       ;; use deprecated APIs and the user doesn't have to know
 369                       ;; about it.
 370                       (parameterize ((guix-warning-port
 371                                       (%make-void-port "w")))
 372                         (primitive-load script)))))
 373             (guile (guile-for-source source)))
 374         ;; BUILD must be a monadic procedure of at least one argument: the
 375         ;; source tree.
 376         ;;
 377         ;; Note: BUILD can return #f if it does not support %PULL-VERSION.  In
 378         ;; the future we'll fall back to a previous version of the protocol
 379         ;; when that happens.
 380         (mbegin %store-monad
 381           (mwhen guile
 382             (set-guile-for-build guile))
 383           (build source #:verbose? verbose? #:version commit
 384                  #:pull-version %pull-version)))
 385
 386       ;; Build a set of modules that extend Guix using the standard method.
 387       (standard-module-derivation name source core dependencies)))
 388
 389 (define* (build-channel-instance instance
 390                                  #:optional core (dependencies '()))
 391   "Return, as a monadic value, the derivation for INSTANCE, a channel
 392 instance.  DEPENDENCIES is a list of extensions providing Guile modules that
 393 INSTANCE depends on."
 394   (build-from-source (symbol->string
 395                       (channel-name (channel-instance-channel instance)))
 396                      (channel-instance-checkout instance)
 397                      #:commit (channel-instance-commit instance)
 398                      #:core core
 399                      #:dependencies dependencies))
 400
 401 (define (resolve-dependencies instances)
 402   "Return a procedure that, given one of the elements of INSTANCES, returns
 403 list of instances it depends on."
 404   (define channel-instance-name
 405     (compose channel-name channel-instance-channel))
 406
 407   (define table                                   ;map a name to an instance
 408     (fold (lambda (instance table)
 409             (vhash-consq (channel-instance-name instance)
 410                          instance table))
 411           vlist-null
 412           instances))
 413
 414   (define edges
 415     (fold (lambda (instance edges)
 416             (fold (lambda (channel edges)
 417                     (let ((name (channel-name channel)))
 418                       (match (vhash-assq name table)
 419                         ((_ . target)
 420                          (vhash-consq instance target edges)))))
 421                   edges
 422                   (channel-instance-dependencies instance)))
 423           vlist-null
 424           instances))
 425
 426   (lambda (instance)
 427     (vhash-foldq* cons '() instance edges)))
 428
 429 (define (channel-instance-derivations instances)
 430   "Return the list of derivations to build INSTANCES, in the same order as
 431 INSTANCES."
 432   (define core-instance
 433     ;; The 'guix' channel is treated specially: it's an implicit dependency of
 434     ;; all the other channels.
 435     (find (lambda (instance)
 436             (guix-channel? (channel-instance-channel instance)))
 437           instances))
 438
 439   (define edges
 440     (resolve-dependencies instances))
 441
 442   (define (instance->derivation instance)
 443     (mlet %store-monad ((system (current-system)))
 444       (mcached (if (eq? instance core-instance)
 445                    (build-channel-instance instance)
 446                    (mlet %store-monad ((core (instance->derivation core-instance))
 447                                        (deps (mapm %store-monad instance->derivation
 448                                                    (edges instance))))
 449                      (build-channel-instance instance core deps)))
 450                instance
 451                system)))
 452
 453   (unless core-instance
 454     (let ((loc (and=> (any (compose channel-location channel-instance-channel)
 455                            instances)
 456                       source-properties->location)))
 457       (raise (apply make-compound-condition
 458                     (condition
 459                      (&message (message "'guix' channel is lacking")))
 460                     (if loc
 461                         (list (condition (&error-location (location loc))))
 462                         '())))))
 463
 464   (mapm %store-monad instance->derivation instances))
 465
 466 (define (whole-package-for-legacy name modules)
 467   "Return a full-blown Guix package for MODULES, a derivation that builds Guix
 468 modules in the old ~/.config/guix/latest style."
 469   (define packages
 470     (resolve-interface '(gnu packages guile)))
 471
 472   (define modules+compiled
 473     ;; Since MODULES contains both .scm and .go files at its root, re-bundle
 474     ;; it so that it has share/guile/site and lib/guile, which is what
 475     ;; 'whole-package' expects.
 476     (computed-file (derivation-name modules)
 477                    (with-imported-modules '((guix build utils))
 478                      #~(begin
 479                          (use-modules (guix build utils))
 480
 481                          (define version
 482                            (effective-version))
 483                          (define share
 484                            (string-append #$output "/share/guile/site"))
 485                          (define lib
 486                            (string-append #$output "/lib/guile/" version))
 487
 488                          (mkdir-p share) (mkdir-p lib)
 489                          (symlink #$modules (string-append share "/" version))
 490                          (symlink #$modules (string-append lib "/site-ccache"))))))
 491
 492   (letrec-syntax ((list (syntax-rules (->)
 493                           ((_)
 494                            '())
 495                           ((_ (module -> variable) rest ...)
 496                            (cons (module-ref (resolve-interface
 497                                               '(gnu packages module))
 498                                              'variable)
 499                                  (list rest ...)))
 500                           ((_ variable rest ...)
 501                            (cons (module-ref packages 'variable)
 502                                  (list rest ...))))))
 503     (whole-package name modules+compiled
 504
 505                    ;; In the "old style", %SELF-BUILD-FILE would simply return a
 506                    ;; derivation that builds modules.  We have to infer what the
 507                    ;; dependencies of these modules were.
 508                    (list guile-json-3 guile-git guile-bytestructures
 509                          (ssh -> guile-ssh) (tls -> gnutls)))))
 510
 511 (define (old-style-guix? drv)
 512   "Return true if DRV corresponds to a ~/.config/guix/latest style of
 513 derivation."
 514   ;; Here we rely on a gross historical fact: that derivations produced by the
 515   ;; "old style" (before commit 8a0d9bc8a3f153159d9e239a151c0fa98f1e12d8,
 516   ;; dated May 30, 2018) did not depend on "guix-command.drv".
 517   (not (find (lambda (input)
 518                (string=? "guix-command"
 519                          (derivation-name
 520                           (derivation-input-derivation input))))
 521              (derivation-inputs drv))))
 522
 523 (define (channel-instances->manifest instances)
 524   "Return a profile manifest with entries for all of INSTANCES, a list of
 525 channel instances."
 526   (define (instance->entry instance drv)
 527     (let ((commit  (channel-instance-commit instance))
 528           (channel (channel-instance-channel instance)))
 529       (manifest-entry
 530         (name (symbol->string (channel-name channel)))
 531         (version (string-take commit 7))
 532         (item (if (guix-channel? channel)
 533                   (if (old-style-guix? drv)
 534                       (whole-package-for-legacy (string-append name "-" version)
 535                                                 drv)
 536                       drv)
 537                   drv))
 538         (properties
 539          `((source (repository
 540                     (version 0)
 541                     (url ,(channel-url channel))
 542                     (branch ,(channel-branch channel))
 543                     (commit ,commit))))))))
 544
 545   (mlet* %store-monad ((derivations (channel-instance-derivations instances))
 546                        (entries ->  (map instance->entry instances derivations)))
 547     (return (manifest entries))))
 548
 549 (define (package-cache-file manifest)
 550   "Build a package cache file for the instance in MANIFEST.  This is meant to
 551 be used as a profile hook."
 552   (mlet %store-monad ((profile (profile-derivation manifest
 553                                                    #:hooks '())))
 554
 555     (define build
 556       #~(begin
 557           (use-modules (gnu packages))
 558
 559           (if (defined? 'generate-package-cache)
 560               (begin
 561                 ;; Delegate package cache generation to the inferior.
 562                 (format (current-error-port)
 563                         "Generating package cache for '~a'...~%"
 564                         #$profile)
 565                 (generate-package-cache #$output))
 566               (mkdir #$output))))
 567
 568     (gexp->derivation-in-inferior "guix-package-cache" build
 569                                   profile
 570
 571                                   ;; If the Guix in PROFILE is too old and
 572                                   ;; lacks 'guix repl', don't build the cache
 573                                   ;; instead of failing.
 574                                   #:silent-failure? #t
 575
 576                                   #:properties '((type . profile-hook)
 577                                                  (hook . package-cache))
 578                                   #:local-build? #t)))
 579
 580 (define %channel-profile-hooks
 581   ;; The default channel profile hooks.
 582   (cons package-cache-file %default-profile-hooks))
 583
 584 (define (channel-instances->derivation instances)
 585   "Return the derivation of the profile containing INSTANCES, a list of
 586 channel instances."
 587   (mlet %store-monad ((manifest (channel-instances->manifest instances)))
 588     (profile-derivation manifest
 589                         #:hooks %channel-profile-hooks)))
 590
 591 (define latest-channel-instances*
 592   (store-lift latest-channel-instances))
 593
 594 (define* (latest-channel-derivation #:optional (channels %default-channels))
 595   "Return as a monadic value the derivation that builds the profile for the
 596 latest instances of CHANNELS."
 597   (mlet %store-monad ((instances (latest-channel-instances* channels)))
 598     (channel-instances->derivation instances)))
 599
 600 (define (profile-channels profile)
 601   "Return the list of channels corresponding to entries in PROFILE.  If
 602 PROFILE is not a profile created by 'guix pull', return the empty list."
 603   (filter-map (lambda (entry)
 604                 (match (assq 'source (manifest-entry-properties entry))
 605                   (('source ('repository ('version 0)
 606                                          ('url url)
 607                                          ('branch branch)
 608                                          ('commit commit)
 609                                          _ ...))
 610                    (channel (name (string->symbol
 611                                    (manifest-entry-name entry)))
 612                             (url url)
 613                             (commit commit)))
 614
 615                   ;; No channel information for this manifest entry.
 616                   ;; XXX: Pre-0.15.0 Guix did not provide that information,
 617                   ;; but there's not much we can do in that case.
 618                   (_ #f)))
 619
 620               ;; Show most recently installed packages last.
 621               (reverse
 622                (manifest-entries (profile-manifest profile)))))
 623
 624 \f
 625 ;;;
 626 ;;; News.
 627 ;;;
 628
 629 ;; Channel news.
 630 (define-record-type <channel-news>
 631   (channel-news entries)
 632   channel-news?
 633   (entries channel-news-entries))                 ;list of <channel-news-entry>
 634
 635 ;; News entry, associated with a specific commit of the channel.
 636 (define-record-type <channel-news-entry>
 637   (channel-news-entry commit tag title body)
 638   channel-news-entry?
 639   (commit  channel-news-entry-commit)             ;hex string | #f
 640   (tag     channel-news-entry-tag)                ;#f | string
 641   (title   channel-news-entry-title)              ;list of language tag/string pairs
 642   (body    channel-news-entry-body))              ;list of language tag/string pairs
 643
 644 (define (sexp->channel-news-entry entry)
 645   "Return the <channel-news-entry> record corresponding to ENTRY, an sexp."
 646   (define (pair language message)
 647     (cons (symbol->string language) message))
 648
 649   (match entry
 650     (('entry ((and (or 'commit 'tag) type) commit-or-tag)
 651              ('title ((? symbol? title-tags) (? string? titles)) ...)
 652              ('body ((? symbol? body-tags) (? string? bodies)) ...)
 653              _ ...)
 654      (channel-news-entry (and (eq? type 'commit) commit-or-tag)
 655                          (and (eq? type 'tag) commit-or-tag)
 656                          (map pair title-tags titles)
 657                          (map pair body-tags bodies)))
 658     (_
 659      (raise (condition
 660              (&message (message "invalid channel news entry"))
 661              (&error-location
 662               (location (source-properties->location
 663                          (source-properties entry)))))))))
 664
 665 (define (read-channel-news port)
 666   "Read a channel news feed from PORT and return it as a <channel-news>
 667 record."
 668   (match (false-if-exception (read port))
 669     (('channel-news ('version 0) entries ...)
 670      (channel-news (map sexp->channel-news-entry entries)))
 671     (('channel-news ('version version) _ ...)
 672      ;; This is an unsupported version from the future.  There's nothing wrong
 673      ;; with that (the user may simply need to upgrade the 'guix' channel to
 674      ;; be able to read it), so silently ignore it.
 675      (channel-news '()))
 676     (#f
 677      (raise (condition
 678              (&message (message "syntactically invalid channel news file")))))
 679     (sexp
 680      (raise (condition
 681              (&message (message "invalid channel news file"))
 682              (&error-location
 683               (location (source-properties->location
 684                          (source-properties sexp)))))))))
 685
 686 (define (resolve-channel-news-entry-tag repository entry)
 687   "If ENTRY has its 'commit' field set, return ENTRY.  Otherwise, lookup
 688 ENTRY's 'tag' in REPOSITORY and return ENTRY with its 'commit' field set to
 689 the field its 'tag' refers to.  A 'git-error' exception is raised if the tag
 690 cannot be found."
 691   (if (channel-news-entry-commit entry)
 692       entry
 693       (let* ((tag       (channel-news-entry-tag entry))
 694              (reference (string-append "refs/tags/" tag))
 695              (oid       (reference-name->oid repository reference)))
 696         (channel-news-entry (oid->string oid) tag
 697                             (channel-news-entry-title entry)
 698                             (channel-news-entry-body entry)))))
 699
 700 (define* (channel-news-for-commit channel new #:optional old)
 701   "Return a list of <channel-news-entry> for CHANNEL between commits OLD and
 702 NEW.  When OLD is omitted or is #f, return all the news entries of CHANNEL."
 703   (catch 'git-error
 704     (lambda ()
 705       (let* ((checkout  (update-cached-checkout (channel-url channel)
 706                                                 #:ref `(commit . ,new)))
 707              (metadata  (read-channel-metadata-from-source checkout))
 708              (news-file (channel-metadata-news-file metadata))
 709              (news-file (and news-file
 710                              (string-append checkout "/" news-file))))
 711         (if (and news-file (file-exists? news-file))
 712             (with-repository checkout repository
 713               (let* ((news    (call-with-input-file news-file
 714                                 read-channel-news))
 715                      (entries (map (lambda (entry)
 716                                      (resolve-channel-news-entry-tag repository
 717                                                                      entry))
 718                                    (channel-news-entries news))))
 719                 (if old
 720                     (let* ((new     (commit-lookup repository (string->oid new)))
 721                            (old     (commit-lookup repository (string->oid old)))
 722                            (commits (list->set
 723                                      (map (compose oid->string commit-id)
 724                                           (commit-difference new old)))))
 725                       (filter (lambda (entry)
 726                                 (set-contains? commits
 727                                                (channel-news-entry-commit entry)))
 728                               entries))
 729                     entries)))
 730             '())))
 731     (lambda (key error . rest)
 732       ;; If commit NEW or commit OLD cannot be found, then something must be
 733       ;; wrong (for example, the history of CHANNEL was rewritten and these
 734       ;; commits no longer exist upstream), so quietly return the empty list.
 735       (if (= GIT_ENOTFOUND (git-error-code error))
 736           '()
 737           (apply throw key error rest)))))