aboutsummaryrefslogtreecommitdiff
path: root/guix/packages.scm
blob: 1939373f3534ce494c114b307cc0d7cc0cb19ae1 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
;;; GNU Guix --- Functional package management for GNU
;;; Copyright © 2012, 2013, 2014 Ludovic Courtès <ludo@gnu.org>
;;;
;;; This file is part of GNU Guix.
;;;
;;; GNU Guix is free software; you can redistribute it and/or modify it
;;; under the terms of the GNU General Public License as published by
;;; the Free Software Foundation; either version 3 of the License, or (at
;;; your option) any later version.
;;;
;;; GNU Guix is distributed in the hope that it will be useful, but
;;; WITHOUT ANY WARRANTY; without even the implied warranty of
;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
;;; GNU General Public License for more details.
;;;
;;; You should have received a copy of the GNU General Public License
;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.

(define-module (guix packages)
  #:use-module (guix utils)
  #:use-module (guix records)
  #:use-module (guix store)
  #:use-module (guix base32)
  #:use-module (guix derivations)
  #:use-module (guix build-system)
  #:use-module (ice-9 match)
  #:use-module (srfi srfi-1)
  #:use-module (srfi srfi-9 gnu)
  #:use-module (srfi srfi-26)
  #:use-module (srfi srfi-34)
  #:use-module (srfi srfi-35)
  #:re-export (%current-system
               %current-target-system)
  #:export (origin
            origin?
            origin-uri
            origin-method
            origin-sha256
            origin-file-name
            origin-patches
            origin-patch-flags
            origin-patch-inputs
            origin-patch-guile
            origin-snippet
            origin-modules
            origin-imported-modules
            base32

            <search-path-specification>
            search-path-specification
            search-path-specification?
            search-path-specification->sexp

            package
            package?
            package-name
            package-version
            package-full-name
            package-source
            package-build-system
            package-arguments
            package-inputs
            package-native-inputs
            package-propagated-inputs
            package-outputs
            package-native-search-paths
            package-search-paths
            package-synopsis
            package-description
            package-license
            package-home-page
            package-platforms
            package-maintainers
            package-properties
            package-location
            package-field-location

            package-direct-inputs
            package-transitive-inputs
            package-transitive-target-inputs
            package-transitive-native-inputs
            package-transitive-propagated-inputs
            package-source-derivation
            package-derivation
            package-cross-derivation
            package-output

            &package-error
            package-error?
            package-error-package
            &package-input-error
            package-input-error?
            package-error-invalid-input
            &package-cross-build-system-error
            package-cross-build-system-error?))

;;; Commentary:
;;;
;;; This module provides a high-level mechanism to define packages in a
;;; Guix-based distribution.
;;;
;;; Code:

;; The source of a package, such as a tarball URL and fetcher---called
;; "origin" to avoid name clash with `package-source', `source', etc.
(define-record-type* <origin>
  origin make-origin
  origin?
  (uri       origin-uri)                          ; string
  (method    origin-method)                       ; procedure
  (sha256    origin-sha256)                       ; bytevector
  (file-name origin-file-name (default #f))       ; optional file name
  (patches   origin-patches (default '()))        ; list of file names
  (snippet   origin-snippet (default #f))         ; sexp or #f
  (patch-flags  origin-patch-flags                ; list of strings
                (default '("-p1")))

  ;; Patching requires Guile, GNU Patch, and a few more.  These two fields are
  ;; used to specify these dependencies when needed.
  (patch-inputs origin-patch-inputs               ; input list or #f
                (default #f))
  (modules      origin-modules                    ; list of module names
                (default '()))
  (imported-modules origin-imported-modules       ; list of module names
                    (default '()))
  (patch-guile origin-patch-guile                 ; package or #f
               (default #f)))

(define (print-origin origin port)
  "Write a concise representation of ORIGIN to PORT."
  (match origin
    (($ <origin> uri method sha256 file-name patches)
     (simple-format port "#<origin ~s ~a ~s ~a>"
                    uri (bytevector->base32-string sha256)
                    patches
                    (number->string (object-address origin) 16)))))

(set-record-type-printer! <origin> print-origin)

(define-syntax base32
  (lambda (s)
    "Return the bytevector corresponding to the given Nix-base32
representation."
    (syntax-case s ()
      ((_ str)
       (string? (syntax->datum #'str))
       ;; A literal string: do the conversion at expansion time.
       (with-syntax ((bv (nix-base32-string->bytevector
                          (syntax->datum #'str))))
         #''bv))
      ((_ str)
       #'(nix-base32-string->bytevector str)))))

;; The specification of a search path.
(define-record-type* <search-path-specification>
  search-path-specification make-search-path-specification
  search-path-specification?
  (variable     search-path-specification-variable)
  (directories  search-path-specification-directories)
  (separator    search-path-specification-separator (default ":")))

(define (search-path-specification->sexp spec)
  "Return an sexp representing SPEC, a <search-path-specification>.  The sexp
corresponds to the arguments expected by `set-path-environment-variable'."
  (match spec
    (($ <search-path-specification> variable directories separator)
     `(,variable ,directories ,separator))))

;; A package.
(define-record-type* <package>
  package make-package
  package?
  (name   package-name)                   ; string
  (version package-version)               ; string
  (source package-source)                 ; <origin> instance
  (build-system package-build-system)     ; build system
  (arguments package-arguments            ; arguments for the build method
             (default '()) (thunked))

  (inputs package-inputs                  ; input packages or derivations
          (default '()) (thunked))
  (propagated-inputs package-propagated-inputs    ; same, but propagated
                     (default '()) (thunked))
  (native-inputs package-native-inputs    ; native input packages/derivations
                 (default '()) (thunked))
  (self-native-input? package-self-native-input?  ; whether to use itself as
                                                  ; a native input when cross-
                      (default #f))               ; compiling

  (outputs package-outputs                ; list of strings
           (default '("out")))

                                                  ; lists of
                                                  ; <search-path-specification>,
                                                  ; for native and cross
                                                  ; inputs
  (native-search-paths package-native-search-paths (default '()))
  (search-paths package-search-paths (default '()))

  (synopsis package-synopsis)                    ; one-line description
  (description package-description)              ; one or two paragraphs
  (license package-license)
  (home-page package-home-page)
  (platforms package-platforms (default '()))
  (maintainers package-maintainers (default '()))

  (properties package-properties (default '()))   ; alist for anything else

  (location package-location
            (default (and=> (current-source-location)
                            source-properties->location))))

(set-record-type-printer! <package>
                          (lambda (package port)
                            (let ((loc    (package-location package))
                                  (format simple-format))
                              (format port "#<package ~a-~a ~a:~a ~a>"
                                      (package-name package)
                                      (package-version package)
                                      (location-file loc)
                                      (location-line loc)
                                      (number->string (object-address
                                                       package)
                                                      16)))))

(define (package-field-location package field)
  "Return the source code location of the definition of FIELD for PACKAGE, or
#f if it could not be determined."
  (define (goto port line column)
    (unless (and (= (port-column port) (- column 1))
                 (= (port-line port) (- line 1)))
      (unless (eof-object? (read-char port))
        (goto port line column))))

  (match (package-location package)
    (($ <location> file line column)
     (catch 'system
       (lambda ()
         ;; In general we want to keep relative file names for modules.
         (with-fluids ((%file-port-name-canonicalization 'relative))
           (call-with-input-file (search-path %load-path file)
             (lambda (port)
               (goto port line column)
               (match (read port)
                 (('package inits ...)
                  (let ((field (assoc field inits)))
                    (match field
                      ((_ value)
                       ;; Put the `or' here, and not in the first argument of
                       ;; `and=>', to work around a compiler bug in 2.0.5.
                       (or (and=> (source-properties value)
                                  source-properties->location)
                           (and=> (source-properties field)
                                  source-properties->location)))
                      (_
                       #f))))
                 (_
                  #f))))))
       (lambda _
         #f)))
    (_ #f)))


;; Error conditions.

(define-condition-type &package-error &error
  package-error?
  (package package-error-package))

(define-condition-type &package-input-error &package-error
  package-input-error?
  (input package-error-invalid-input))

(define-condition-type &package-cross-build-system-error &package-error
  package-cross-build-system-error?)


(define (package-full-name package)
  "Return the full name of PACKAGE--i.e., `NAME-VERSION'."
  (string-append (package-name package) "-" (package-version package)))

(define (%standard-patch-inputs)
  (let ((ref (lambda (module var)
               (module-ref (resolve-interface module) var))))
    `(("tar"   ,(ref '(gnu packages base) 'tar))
      ("xz"    ,(ref '(gnu packages compression) 'xz))
      ("bzip2" ,(ref '(gnu packages compression) 'bzip2))
      ("gzip"  ,(ref '(gnu packages compression) 'gzip))
      ("lzip"  ,(ref '(gnu packages compression) 'lzip))
      ("patch" ,(ref '(gnu packages base) 'patch)))))

(define (default-guile)
  "Return the default Guile package for SYSTEM."
  (let ((distro (resolve-interface '(gnu packages base))))
    (module-ref distro 'guile-final)))

(define* (patch-and-repack store source patches
                           #:key
                           (inputs '())
                           (snippet #f)
                           (flags '("-p1"))
                           (modules '())
                           (imported-modules '())
                           (guile-for-build (%guile-for-build))
                           (system (%current-system)))
  "Unpack SOURCE (a derivation or store path), apply all of PATCHES, and
repack the tarball using the tools listed in INPUTS.  When SNIPPET is true,
it must be an s-expression that will run from within the directory where
SOURCE was unpacked, after all of PATCHES have been applied.  MODULES and
IMPORTED-MODULES specify modules to use/import for use by SNIPPET."
  (define source-file-name
    ;; SOURCE is usually a derivation, but it could be a store file.
    (if (derivation? source)
        (derivation->output-path source)
        source))

  (define decompression-type
    (cond ((string-suffix? "gz" source-file-name)  "gzip")
          ((string-suffix? "bz2" source-file-name) "bzip2")
          ((string-suffix? "lz" source-file-name)  "lzip")
          (else "xz")))

  (define original-file-name
    ;; Remove the store prefix plus the slash, hash, and hyphen.
    (let* ((sans (string-drop source-file-name
                              (+ (string-length (%store-prefix)) 1)))
           (dash (string-index sans #\-)))
      (string-drop sans (+ 1 dash))))

  (define (numeric-extension? file-name)
    ;; Return true if FILE-NAME ends with digits.
    (and=> (file-extension file-name)
           (cut string-every char-set:hex-digit <>)))

  (define (tarxz-name file-name)
    ;; Return a '.tar.xz' file name based on FILE-NAME.
    (let ((base (if (numeric-extension? file-name)
                    original-file-name
                    (file-sans-extension file-name))))
      (string-append base
                     (if (equal? (file-extension base) "tar")
                         ".xz"
                         ".tar.xz"))))

  (define patch-inputs
    (map (lambda (number patch)
           (list (string-append "patch" (number->string number))
                 (add-to-store store (basename patch) #t
                               "sha256" patch)))
         (iota (length patches))

         patches))

  (define builder
    `(begin
       (use-modules (ice-9 ftw)
                    (srfi srfi-1)
                    (guix build utils))

       (let ((out     (assoc-ref %outputs "out"))
             (xz      (assoc-ref %build-inputs "xz"))
             (decomp  (assoc-ref %build-inputs ,decompression-type))
             (source  (assoc-ref %build-inputs "source"))
             (tar     (string-append (assoc-ref %build-inputs "tar")
                                     "/bin/tar"))
             (patch   (string-append (assoc-ref %build-inputs "patch")
                                     "/bin/patch")))
         (define (apply-patch input)
           (let ((patch* (assoc-ref %build-inputs input)))
             (format (current-error-port) "applying '~a'...~%" patch*)
             (zero? (system* patch "--batch" ,@flags "--input" patch*))))

         (define (first-file directory)
           ;; Return the name of the first file in DIRECTORY.
           (car (scandir directory
                         (lambda (name)
                           (not (member name '("." "..")))))))

         (setenv "PATH" (string-append xz "/bin" ":"
                                       decomp "/bin"))

         ;; SOURCE may be either a directory or a tarball.
         (and (if (file-is-directory? source)
                  (let* ((store     (or (getenv "NIX_STORE") "/gnu/store"))
                         (len       (+ 1 (string-length store)))
                         (base      (string-drop source len))
                         (dash      (string-index base #\-))
                         (directory (string-drop base (+ 1 dash))))
                    (mkdir directory)
                    (copy-recursively source directory)
                    #t)
                  (zero? (system* tar "xvf" source)))
              (let ((directory (first-file ".")))
                (format (current-error-port)
                        "source is under '~a'~%" directory)
                (chdir directory)

                (and (every apply-patch ',(map car patch-inputs))

                     ,@(if snippet
                           `((let ((module (make-fresh-user-module)))
                               (module-use-interfaces! module
                                                       (map resolve-interface
                                                            ',modules))
                               (module-define! module '%build-inputs
                                               %build-inputs)
                               (module-define! module '%outputs %outputs)
                               ((@ (system base compile) compile)
                                ',snippet
                                #:to 'value
                                #:opts %auto-compilation-options
                                #:env module)))
                           '())

                     (begin (chdir "..") #t)
                     (zero? (system* tar "cvfa" out directory))))))))


  (let ((name    (tarxz-name original-file-name))
        (inputs  (filter-map (match-lambda
                              ((name (? package? p))
                               (and (member name (cons decompression-type
                                                       '("tar" "xz" "patch")))
                                    (list name
                                          (package-derivation store p
                                                              system)))))
                             (or inputs (%standard-patch-inputs))))
        (modules (delete-duplicates (cons '(guix build utils) modules))))

    (build-expression->derivation store name builder
                                 #:inputs `(("source" ,source)
                                            ,@inputs
                                            ,@patch-inputs)
                                 #:system system
                                 #:modules modules
                                 #:guile-for-build guile-for-build)))

(define* (package-source-derivation store source
                                    #:optional (system (%current-system)))
  "Return the derivation path for SOURCE, a package source, for SYSTEM."
  (match source
    (($ <origin> uri method sha256 name () #f)
     ;; No patches, no snippet: this is a fixed-output derivation.
     (method store uri 'sha256 sha256 name
             #:system system))
    (($ <origin> uri method sha256 name (patches ...) snippet
        (flags ...) inputs (modules ...) (imported-modules ...)
        guile-for-build)
     ;; Patches and/or a snippet.
     (let ((source (method store uri 'sha256 sha256 name
                           #:system system))
           (guile  (match (or guile-for-build (%guile-for-build)
                              (default-guile))
                     ((? package? p)
                      (package-derivation store p system))
                     ((? derivation? drv)
                      drv))))
       (patch-and-repack store source patches
                         #:inputs inputs
                         #:snippet snippet
                         #:flags flags
                         #:system system
                         #:modules modules
                         #:imported-modules modules
                         #:guile-for-build guile)))
    ((and (? string?) (? direct-store-path?) file)
     file)
    ((? string? file)
     (add-to-store store (basename file) #t "sha256" file))))

(define (transitive-inputs inputs)
  (let loop ((inputs  inputs)
             (result '()))
    (match inputs
      (()
       (delete-duplicates (reverse result)))      ; XXX: efficiency
      (((and i (name (? package? p) sub ...)) rest ...)
       (let ((t (map (match-lambda
                      ((dep-name derivation ...)
                       (cons (string-append name "/" dep-name)
                             derivation)))
                     (package-propagated-inputs p))))
         (loop (append t rest)
               (append t (cons i result)))))
      ((input rest ...)
       (loop rest (cons input result))))))

(define (package-direct-inputs package)
  "Return all the direct inputs of PACKAGE---i.e, its direct inputs along
with their propagated inputs."
  (append (package-native-inputs package)
          (package-inputs package)
          (package-propagated-inputs package)))

(define (package-transitive-inputs package)
  "Return the transitive inputs of PACKAGE---i.e., its direct inputs along
with their propagated inputs, recursively."
  (transitive-inputs (package-direct-inputs package)))

(define (package-transitive-target-inputs package)
  "Return the transitive target inputs of PACKAGE---i.e., its direct inputs
along with their propagated inputs, recursively.  This only includes inputs
for the target system, and not native inputs."
  (transitive-inputs (append (package-inputs package)
                             (package-propagated-inputs package))))

(define (package-transitive-native-inputs package)
  "Return the transitive native inputs of PACKAGE---i.e., its direct inputs
along with their propagated inputs, recursively.  This only includes inputs
for the host system (\"native inputs\"), and not target inputs."
  (transitive-inputs (package-native-inputs package)))

(define (package-transitive-propagated-inputs package)
  "Return the propagated inputs of PACKAGE, and their propagated inputs,
recursively."
  (transitive-inputs (package-propagated-inputs package)))


;;;
;;; Package derivations.
;;;

(define %derivation-cache
  ;; Package to derivation-path mapping.
  (make-weak-key-hash-table 100))

(define (cache package system thunk)
  "Memoize the return values of THUNK as the derivation of PACKAGE on
SYSTEM."
  ;; FIXME: This memoization should be associated with the open store, because
  ;; otherwise it breaks when switching to a different store.
  (let ((vals (call-with-values thunk list)))
    ;; Use `hashq-set!' instead of `hash-set!' because `hash' returns the
    ;; same value for all structs (as of Guile 2.0.6), and because pointer
    ;; equality is sufficient in practice.
    (hashq-set! %derivation-cache package `((,system ,@vals)))
    (apply values vals)))

(define-syntax-rule (cached package system body ...)
  "Memoize the result of BODY for the arguments PACKAGE and SYSTEM.
Return the cached result when available."
  (let ((thunk (lambda () body ...)))
    (match (hashq-ref %derivation-cache package)
      ((alist (... ...))
       (match (assoc-ref alist system)
         ((vals (... ...))
          (apply values vals))
         (#f
          (cache package system thunk))))
      (#f
       (cache package system thunk)))))

(define* (expand-input store package input system #:optional cross-system)
  "Expand INPUT, an input tuple, such that it contains only references to
derivation paths or store paths.  PACKAGE is only used to provide contextual
information in exceptions."
  (define (intern file)
    ;; Add FILE to the store.  Set the `recursive?' bit to #t, so that
    ;; file permissions are preserved.
    (add-to-store store (basename file) #t "sha256" file))

  (define derivation
    (if cross-system
        (cut package-cross-derivation store <> cross-system system)
        (cut package-derivation store <> system)))

  (match input
    (((? string? name) (? package? package))
     (list name (derivation package)))
    (((? string? name) (? package? package)
      (? string? sub-drv))
     (list name (derivation package)
           sub-drv))
    (((? string? name)
      (and (? string?) (? derivation-path?) drv))
     (list name drv))
    (((? string? name)
      (and (? string?) (? file-exists? file)))
     ;; Add FILE to the store.  When FILE is in the sub-directory of a
     ;; store path, it needs to be added anyway, so it can be used as a
     ;; source.
     (list name (intern file)))
    (((? string? name) (? origin? source))
     (list name (package-source-derivation store source system)))
    (x
     (raise (condition (&package-input-error
                        (package package)
                        (input   x)))))))

(define* (package-derivation store package
                             #:optional (system (%current-system)))
  "Return the <derivation> object of PACKAGE for SYSTEM."

  ;; Compute the derivation and cache the result.  Caching is important
  ;; because some derivations, such as the implicit inputs of the GNU build
  ;; system, will be queried many, many times in a row.
  (cached package system

          ;; Bind %CURRENT-SYSTEM so that thunked field values can refer
          ;; to it.
          (parameterize ((%current-system system)
                         (%current-target-system #f))
            (match package
              (($ <package> name version source (= build-system-builder builder)
                  args inputs propagated-inputs native-inputs self-native-input?
                  outputs)
               (let* ((inputs     (package-transitive-inputs package))
                      (input-drvs (map (cut expand-input
                                            store package <> system)
                                       inputs))
                      (paths      (delete-duplicates
                                   (append-map (match-lambda
                                                ((_ (? package? p) _ ...)
                                                 (package-native-search-paths
                                                  p))
                                                (_ '()))
                                               inputs))))

                 (apply builder
                        store (package-full-name package)
                        (and source
                             (package-source-derivation store source system))
                        input-drvs
                        #:search-paths paths
                        #:outputs outputs #:system system
                        (args))))))))

(define* (package-cross-derivation store package target
                                   #:optional (system (%current-system)))
  "Cross-build PACKAGE for TARGET (a GNU triplet) from host SYSTEM (a Guix
system identifying string)."
  (cached package (cons system target)

          ;; Bind %CURRENT-SYSTEM so that thunked field values can refer
          ;; to it.
          (parameterize ((%current-system system)
                         (%current-target-system target))
            (match package
              (($ <package> name version source
                  (= build-system-cross-builder builder)
                  args inputs propagated-inputs native-inputs self-native-input?
                  outputs)
               (unless builder
                 (raise (condition
                         (&package-cross-build-system-error
                          (package package)))))

               (let* ((inputs     (package-transitive-target-inputs package))
                      (input-drvs (map (cut expand-input
                                            store package <>
                                            system target)
                                       inputs))
                      (host       (append (if self-native-input?
                                              `(("self" ,package))
                                              '())
                                          (package-transitive-native-inputs package)))
                      (host-drvs  (map (cut expand-input
                                            store package <> system)
                                       host))
                      (all        (append host inputs))
                      (paths      (delete-duplicates
                                   (append-map (match-lambda
                                                ((_ (? package? p) _ ...)
                                                 (package-search-paths p))
                                                (_ '()))
                                               all)))
                      (npaths     (delete-duplicates
                                   (append-map (match-lambda
                                                ((_ (? package? p) _ ...)
                                                 (package-native-search-paths
                                                  p))
                                                (_ '()))
                                               all))))

                 (apply builder
                        store (package-full-name package) target
                        (and source
                             (package-source-derivation store source system))
                        input-drvs host-drvs
                        #:search-paths paths
                        #:native-search-paths npaths
                        #:outputs outputs #:system system
                        (args))))))))

(define* (package-output store package
                         #:optional (output "out") (system (%current-system)))
  "Return the output path of PACKAGE's OUTPUT for SYSTEM---where OUTPUT is the
symbolic output name, such as \"out\".  Note that this procedure calls
`package-derivation', which is costly."
  (let ((drv (package-derivation store package system)))
    (derivation->output-path drv output)))