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[bug#45774,core-updates,v2] build-systems/gnu: Allow unpacking/repacking more kind of files.

Message ID 20210113174021.23960-1-maxim.cournoyer@gmail.com
State New
Headers show
Series [bug#45774,core-updates,v2] build-systems/gnu: Allow unpacking/repacking more kind of files. | expand

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Commit Message

Maxim Cournoyer Jan. 13, 2021, 5:40 p.m. UTC
Before this change, only plain directories, tar or zip archives were supported
as the source of a package for the GNU build system; anything else would cause
the unpack phase to fail.  Origins relying on snippets would suffer from the
same problem.

This change adds the support to use files of the following extensions: .gz,
.Z, .bz2, .lz, and .xz, even when they are not tarballs.  Files of unknown
extensions are treated as uncompressed files and supported as well.

* guix/packages.scm (patch-and-repack): Only add the compressor utility to the
PATH when the file is compressed.  Bind more inputs in the mlet, and use them
for decompressing single files.  Adjust decompression and compression routines.
[decompression-type]: Return #f when no known compression extension is used.
[tarball?]: New nested procedure.
* guix/build/utils.scm (compressor, tarball?): New procedures.  Move
%xz-parallel-args to the new 'compression helpers' section.
* tests/packages.scm: Add tests.  Add missing copyright year for Jan.
* guix/build/gnu-build-system.scm (first-subdirectory): Return #f when no
sub-directory was found.
(unpack): Support more file types, including uncompressed plain files.
---
 guix/build/gnu-build-system.scm |  24 ++++++--
 guix/build/utils.scm            |  47 ++++++++++-----
 guix/packages.scm               | 100 +++++++++++++++++---------------
 guix/tests.scm                  |  40 ++++++++++++-
 tests/builders.scm              |  40 ++++++++++++-
 tests/packages.scm              |  69 +++++++++++++++++++++-
 6 files changed, 247 insertions(+), 73 deletions(-)

Comments

Ludovic Courtès Jan. 14, 2021, 5:48 p.m. UTC | #1
Hi!

Maxim Cournoyer <maxim.cournoyer@gmail.com> skribis:

> Before this change, only plain directories, tar or zip archives were supported
> as the source of a package for the GNU build system; anything else would cause
> the unpack phase to fail.  Origins relying on snippets would suffer from the
> same problem.
>
> This change adds the support to use files of the following extensions: .gz,
> .Z, .bz2, .lz, and .xz, even when they are not tarballs.  Files of unknown
> extensions are treated as uncompressed files and supported as well.
>
> * guix/packages.scm (patch-and-repack): Only add the compressor utility to the
> PATH when the file is compressed.  Bind more inputs in the mlet, and use them
> for decompressing single files.  Adjust decompression and compression routines.
> [decompression-type]: Return #f when no known compression extension is used.
> [tarball?]: New nested procedure.
> * guix/build/utils.scm (compressor, tarball?): New procedures.  Move
> %xz-parallel-args to the new 'compression helpers' section.
> * tests/packages.scm: Add tests.  Add missing copyright year for Jan.
> * guix/build/gnu-build-system.scm (first-subdirectory): Return #f when no
> sub-directory was found.
> (unpack): Support more file types, including uncompressed plain files.
> ---
>  guix/build/gnu-build-system.scm |  24 ++++++--
>  guix/build/utils.scm            |  47 ++++++++++-----
>  guix/packages.scm               | 100 +++++++++++++++++---------------
>  guix/tests.scm                  |  40 ++++++++++++-
>  tests/builders.scm              |  40 ++++++++++++-
>  tests/packages.scm              |  69 +++++++++++++++++++++-
>  6 files changed, 247 insertions(+), 73 deletions(-)

How frequent is it for an origin to be a regular file other than an
archive?  The underlying question for me is: will this generalization
and increased complexity pay off?  WDYT?

There are aspects of the patch that I find welcome regardless, such as
the improved handling of compression helpers.

Thanks,
Ludo’.
Maxim Cournoyer Jan. 14, 2021, 6:43 p.m. UTC | #2
Hi Ludovic,

Ludovic Courtès <ludo@gnu.org> writes:

> Hi!
>
> Maxim Cournoyer <maxim.cournoyer@gmail.com> skribis:
>
>> Before this change, only plain directories, tar or zip archives were supported
>> as the source of a package for the GNU build system; anything else would cause
>> the unpack phase to fail.  Origins relying on snippets would suffer from the
>> same problem.
>>
>> This change adds the support to use files of the following extensions: .gz,
>> .Z, .bz2, .lz, and .xz, even when they are not tarballs.  Files of unknown
>> extensions are treated as uncompressed files and supported as well.
>>
>> * guix/packages.scm (patch-and-repack): Only add the compressor utility to the
>> PATH when the file is compressed.  Bind more inputs in the mlet, and use them
>> for decompressing single files.  Adjust decompression and compression routines.
>> [decompression-type]: Return #f when no known compression extension is used.
>> [tarball?]: New nested procedure.
>> * guix/build/utils.scm (compressor, tarball?): New procedures.  Move
>> %xz-parallel-args to the new 'compression helpers' section.
>> * tests/packages.scm: Add tests.  Add missing copyright year for Jan.
>> * guix/build/gnu-build-system.scm (first-subdirectory): Return #f when no
>> sub-directory was found.
>> (unpack): Support more file types, including uncompressed plain files.
>> ---
>>  guix/build/gnu-build-system.scm |  24 ++++++--
>>  guix/build/utils.scm            |  47 ++++++++++-----
>>  guix/packages.scm               | 100 +++++++++++++++++---------------
>>  guix/tests.scm                  |  40 ++++++++++++-
>>  tests/builders.scm              |  40 ++++++++++++-
>>  tests/packages.scm              |  69 +++++++++++++++++++++-
>>  6 files changed, 247 insertions(+), 73 deletions(-)
>
> How frequent is it for an origin to be a regular file other than an
> archive?  The underlying question for me is: will this generalization
> and increased complexity pay off?  WDYT?

I think consistency is the main driver here.  The url-fetch method
supports single file sources; it makes sense that the other components
handling sources support it as well.  It's hard to judge of the
popularity of such a feature when it's never been available; but some
use cases come to mind such as single Emacs package file.  I've made use
of such feature for the new texlive-updmap.cfg definition in
<http://issues.guix.gnu.org/45870>.

> There are aspects of the patch that I find welcome regardless, such as
> the improved handling of compression helpers.

Great!  Thanks for looking at it.

Maxim
diff mbox series

Patch

diff --git a/guix/build/gnu-build-system.scm b/guix/build/gnu-build-system.scm
index e556457db9..d36aecb75e 100644
--- a/guix/build/gnu-build-system.scm
+++ b/guix/build/gnu-build-system.scm
@@ -2,6 +2,7 @@ 
 ;;; Copyright © 2012, 2013, 2014, 2015, 2016, 2017, 2018, 2019, 2020 Ludovic Courtès <ludo@gnu.org>
 ;;; Copyright © 2018 Mark H Weaver <mhw@netris.org>
 ;;; Copyright © 2020 Brendan Tildesley <mail@brendan.scot>
+;;; Copyright © 2021 Maxim Cournoyer <maxim.cournoyer@gmail.com>
 ;;;
 ;;; This file is part of GNU Guix.
 ;;;
@@ -60,13 +61,15 @@  See https://reproducible-builds.org/specs/source-date-epoch/."
   (setenv "SOURCE_DATE_EPOCH" "1"))
 
 (define (first-subdirectory directory)
-  "Return the file name of the first sub-directory of DIRECTORY."
+  "Return the file name of the first sub-directory of DIRECTORY or false, when
+there are none."
   (match (scandir directory
                   (lambda (file)
                     (and (not (member file '("." "..")))
                          (file-is-directory? (string-append directory "/"
                                                             file)))))
-    ((first . _) first)))
+    ((first . _) first)
+    (_ #f)))
 
 (define* (set-paths #:key target inputs native-inputs
                     (search-paths '()) (native-search-paths '())
@@ -155,10 +158,19 @@  working directory."
         (copy-recursively source "."
                           #:keep-mtime? #t))
       (begin
-        (if (string-suffix? ".zip" source)
-            (invoke "unzip" source)
-            (invoke "tar" "xvf" source))
-        (chdir (first-subdirectory ".")))))
+        (cond
+         ((string-suffix? ".zip" source)
+          (invoke "unzip" source))
+         ((tarball? source)
+          (invoke "tar" "xvf" source))
+         (else
+          (let ((name (strip-store-file-name source))
+                (command (compressor source)))
+            (copy-file source name)
+            (when command
+              (invoke command "--decompress" name)))))
+        ;; Attempt to change into child directory.
+        (and=> (first-subdirectory ".") chdir))))
 
 (define* (bootstrap #:key bootstrap-scripts
                     #:allow-other-keys)
diff --git a/guix/build/utils.scm b/guix/build/utils.scm
index 76180e67e0..5e7ac74033 100644
--- a/guix/build/utils.scm
+++ b/guix/build/utils.scm
@@ -6,7 +6,7 @@ 
 ;;; Copyright © 2018 Arun Isaac <arunisaac@systemreboot.net>
 ;;; Copyright © 2018, 2019 Ricardo Wurmus <rekado@elephly.net>
 ;;; Copyright © 2020 Efraim Flashner <efraim@flashner.co.il>
-;;; Copyright © 2020 Maxim Cournoyer <maxim.cournoyer@gmail.com>
+;;; Copyright © 2020, 2021 Maxim Cournoyer <maxim.cournoyer@gmail.com>
 ;;;
 ;;; This file is part of GNU Guix.
 ;;;
@@ -51,6 +51,10 @@ 
             package-name->name+version
             parallel-job-count
 
+            compressor
+            tarball?
+            %xz-parallel-args
+
             directory-exists?
             executable-file?
             symbolic-link?
@@ -113,9 +117,7 @@ 
 
             make-desktop-entry-file
 
-            locale-category->string
-
-            %xz-parallel-args))
+            locale-category->string))
 
 
 ;;;
@@ -137,6 +139,32 @@ 
    (module-replace! (current-module) '(setvbuf)))
   (else #f))
 
+
+;;;
+;;; Compression helpers.
+;;;
+
+(define (compressor file-name)
+  "Return the name of the compressor package/binary used to compress or
+decompress FILE-NAME, based on its file extension, else false."
+  (cond ((string-suffix? "gz"  file-name)  "gzip")
+        ((string-suffix? "Z"   file-name)  "gzip")
+        ((string-suffix? "bz2" file-name)  "bzip2")
+        ((string-suffix? "lz"  file-name)  "lzip")
+        ((string-suffix? "zip" file-name)  "unzip")
+        ((string-suffix? "xz"  file-name)  "xz")
+        (else #f)))                ;no compression used/unknown file extension
+
+(define (tarball? file-name)
+  "True when FILE-NAME has a tar file extension."
+  (string-match "\\.(tar(\\..*)?|tgz|tbz)$" file-name))
+
+(define (%xz-parallel-args)
+  "The xz arguments required to enable bit-reproducible, multi-threaded
+compression."
+  (list "--memlimit=50%"
+        (format #f "--threads=~a" (max 2 (parallel-job-count)))))
+
 
 ;;;
 ;;; Directories.
@@ -1536,17 +1564,6 @@  returned."
              LC_NAME LC_NUMERIC LC_PAPER LC_TELEPHONE
              LC_TIME)))
 
-
-;;;
-;;; Others.
-;;;
-
-(define (%xz-parallel-args)
-  "The xz arguments required to enable bit-reproducible, multi-threaded
-compression."
-  (list "--memlimit=50%"
-        (format #f "--threads=~a" (max 2 (parallel-job-count)))))
-
 ;;; Local Variables:
 ;;; eval: (put 'call-with-output-file/atomic 'scheme-indent-function 1)
 ;;; eval: (put 'call-with-ascii-input-file 'scheme-indent-function 1)
diff --git a/guix/packages.scm b/guix/packages.scm
index 4caaa9cb79..8f4dc7ec36 100644
--- a/guix/packages.scm
+++ b/guix/packages.scm
@@ -5,7 +5,7 @@ 
 ;;; Copyright © 2016 Alex Kost <alezost@gmail.com>
 ;;; Copyright © 2017, 2019, 2020 Efraim Flashner <efraim@flashner.co.il>
 ;;; Copyright © 2019 Marius Bakke <mbakke@fastmail.com>
-;;; Copyright © 2020 Maxim Cournoyer <maxim.cournoyer@gmail.com>
+;;; Copyright © 2020, 2021 Maxim Cournoyer <maxim.cournoyer@gmail.com>
 ;;;
 ;;; This file is part of GNU Guix.
 ;;;
@@ -23,6 +23,7 @@ 
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
 (define-module (guix packages)
+  #:use-module ((guix build utils) #:select (compressor tarball?))
   #:use-module (guix utils)
   #:use-module (guix records)
   #:use-module (guix store)
@@ -609,14 +610,6 @@  specifies modules in scope when evaluating SNIPPET."
           ((package) package)
           (#f        #f)))))
 
-  (define decompression-type
-    (cond ((string-suffix? "gz" source-file-name)  "gzip")
-          ((string-suffix? "Z" source-file-name)  "gzip")
-          ((string-suffix? "bz2" source-file-name) "bzip2")
-          ((string-suffix? "lz" source-file-name)  "lzip")
-          ((string-suffix? "zip" source-file-name) "unzip")
-          (else "xz")))
-
   (define original-file-name
     ;; Remove the store prefix plus the slash, hash, and hyphen.
     (let* ((sans (string-drop source-file-name
@@ -653,17 +646,24 @@  specifies modules in scope when evaluating SNIPPET."
        (lower-object patch system))))
 
   (mlet %store-monad ((tar ->     (lookup-input "tar"))
+                      (gzip ->    (lookup-input "gzip"))
+                      (bzip2 ->   (lookup-input "bzip2"))
+                      (lzip ->    (lookup-input "lzip"))
                       (xz ->      (lookup-input "xz"))
                       (patch ->   (lookup-input "patch"))
                       (locales -> (lookup-input "locales"))
-                      (decomp ->  (lookup-input decompression-type))
+                      (comp ->    (and=> (compressor source-file-name)
+                                         lookup-input))
                       (patches    (sequence %store-monad
                                             (map instantiate-patch patches))))
     (define build
       (with-imported-modules '((guix build utils))
         #~(begin
             (use-modules (ice-9 ftw)
+                         (ice-9 match)
+                         (ice-9 regex)
                          (srfi srfi-1)
+                         (srfi srfi-26)
                          (guix build utils))
 
             ;; The --sort option was added to GNU tar in version 1.28, released
@@ -702,45 +702,53 @@  specifies modules in scope when evaluating SNIPPET."
                                              (package-version locales)))))
               (setlocale LC_ALL "en_US.utf8"))
 
-            (setenv "PATH" (string-append #+xz "/bin" ":"
-                                          #+decomp "/bin"))
+            (setenv "PATH"
+                    (string-append #+xz "/bin"
+                                   (if #+comp
+                                       (string-append ":" #+comp "/bin")
+                                       "")))
 
             (setenv "XZ_DEFAULTS" (string-join (%xz-parallel-args)))
 
-            ;; SOURCE may be either a directory or a tarball.
-            (if (file-is-directory? #+source)
-                (let* ((store     (%store-directory))
-                       (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))
-                #+(if (string=? decompression-type "unzip")
-                      #~(invoke "unzip" #+source)
-                      #~(invoke (string-append #+tar "/bin/tar")
-                                "xvf" #+source)))
-
-            (let ((directory (first-file ".")))
-              (format (current-error-port)
-                      "source is under '~a'~%" directory)
-              (chdir directory)
-
-              (for-each apply-patch '#+patches)
-
-              #+(if snippet
-                    #~(let ((module (make-fresh-user-module)))
-                        (module-use-interfaces!
-                         module
-                         (map resolve-interface '#+modules))
-                        ((@ (system base compile) compile)
-                         '#+snippet
-                         #:to 'value
-                         #:opts %auto-compilation-options
-                         #:env module))
-                    #~#t)
-
-              (chdir "..")
+            ;; SOURCE may be either a directory, a tarball or a simple file.
+            (let ((name (strip-store-file-name #+source))
+                  (command (and=> #+comp (cut string-append <> "/bin/"
+                                              (compressor #+source)))))
+              (if (file-is-directory? #+source)
+                  (copy-recursively #+source name)
+                  (cond
+                   ((tarball? #+source)
+                    (invoke (string-append #+tar "/bin/tar") "xvf" #+source))
+                   ((and=> (compressor #+source) (cut string= "unzip" <>))
+                    ;; Note: Referring to the store unzip here (#+unzip)
+                    ;; would introduce a cycle.
+                    ("unzip" (invoke "unzip" #+source)))
+                   (else
+                    (copy-file #+source name)
+                    (when command
+                      (invoke command "--decompress" name))))))
+
+            (let* ((file (first-file "."))
+                   (directory (if (file-is-directory? file)
+                                  file
+                                  ".")))
+              (format (current-error-port) "source is at '~a'~%" file)
+
+              (with-directory-excursion directory
+
+                (for-each apply-patch '#+patches)
+
+                #+(if snippet
+                      #~(let ((module (make-fresh-user-module)))
+                          (module-use-interfaces!
+                           module
+                           (map resolve-interface '#+modules))
+                          ((@ (system base compile) compile)
+                           '#+snippet
+                           #:to 'value
+                           #:opts %auto-compilation-options
+                           #:env module))
+                      #~#t))
 
               (unless tar-supports-sort?
                 (call-with-output-file ".file_list"
diff --git a/guix/tests.scm b/guix/tests.scm
index fc3d521163..daf4a4d15f 100644
--- a/guix/tests.scm
+++ b/guix/tests.scm
@@ -20,12 +20,13 @@ 
   #:use-module ((guix config) #:select (%storedir %localstatedir))
   #:use-module (guix store)
   #:use-module (guix derivations)
+  #:use-module (guix gexp)
   #:use-module (guix packages)
   #:use-module (guix base32)
   #:use-module (guix serialization)
   #:use-module (guix monads)
   #:use-module ((guix utils) #:select (substitute-keyword-arguments))
-  #:use-module ((guix build utils) #:select (mkdir-p))
+  #:use-module ((guix build utils) #:select (mkdir-p compressor))
   #:use-module ((gcrypt hash) #:hide (sha256))
   #:use-module (guix build-system gnu)
   #:use-module (gnu packages base)
@@ -60,7 +61,9 @@ 
             dummy-package
             dummy-origin
 
-            gnu-make-for-tests))
+            gnu-make-for-tests
+
+            test-file))
 
 ;;; Commentary:
 ;;;
@@ -435,6 +438,39 @@  default values, and with EXTRA-FIELDS set as specified."
      (native-inputs '())                          ;no need for 'pkg-config'
      (inputs %bootstrap-inputs-for-tests))))
 
+
+;;;
+;;; Test utility procedures.
+
+(define (test-file store name content)
+  "Create a simple file in STORE with CONTENT (a string), compressed according
+to its file name extension.  Return both its file name and its hash."
+  (let* ((name-sans-ext (string-take name (string-index-right name #\.)))
+         (comp (compressor name))
+         (command #~(if #+comp
+                        (string-append #+%bootstrap-coreutils&co
+                                       "/bin/" #+comp)
+                        #f))
+         (f (with-imported-modules '((guix build utils))
+              (computed-file name
+                             #~(begin
+                                 (use-modules (guix build utils)
+                                              (rnrs io simple))
+                                 (with-output-to-file #+name-sans-ext
+                                   (lambda _
+                                     (format #t #+content)))
+                                 (when #+command
+                                   (invoke #+command #+name-sans-ext))
+                                 (copy-file #+name #$output)))))
+         (file-drv (run-with-store store (lower-object f)))
+         (file (derivation->output-path file-drv))
+         (file-drv-outputs (derivation-outputs file-drv))
+         (_ (build-derivations store (list file-drv)))
+         (file-hash (derivation-output-hash
+                     (assoc-ref file-drv-outputs "out"))))
+    (values file file-hash)))
+
+;;;
 ;; Local Variables:
 ;; eval: (put 'call-with-derivation-narinfo 'scheme-indent-function 1)
 ;; eval: (put 'call-with-derivation-substitute 'scheme-indent-function 2)
diff --git a/tests/builders.scm b/tests/builders.scm
index fdcf38ded3..7b9cfca362 100644
--- a/tests/builders.scm
+++ b/tests/builders.scm
@@ -17,7 +17,7 @@ 
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
 
-(define-module (test-builders)
+(define-module (tests builders)
   #:use-module (guix download)
   #:use-module (guix build-system)
   #:use-module (guix build-system gnu)
@@ -78,4 +78,42 @@ 
 (test-assert "gnu-build-system"
   (build-system? gnu-build-system))
 
+;;; FIXME: The following fails because the store file names of the test-env
+;;; environment are longer than the real ones, so strip-store-file-name
+;;; doesn't work as intended.
+
+;; (use-modules (guix build gnu-build-system)
+;;              (guix build utils)
+;;              (ice-9 textual-ports)
+;;              (srfi srfi-11))
+
+;; (define unpack (assoc-ref %standard-phases 'unpack))
+;
+;; (define compressors '(("gzip"  . "gz")
+;;                       ("xz"    . "xz")
+;;                       ("bzip2" . "bz2")
+;;                       (#f      . #f)))
+
+;; (for-each
+;;  (match-lambda
+;;    ((comp . ext)
+
+;;     (unless (network-reachable?) (test-skip 1)) ;for bootstrap binaries
+;;     (test-equal (string-append "gnu-build-system unpack phase, "
+;;                                 "single file (compression: "
+;;                                 (if comp comp "None") ")")
+;;       "expected text"
+;;       (let*-values
+;;           (((name) "test")
+;;            ((compressed-name) (if ext
+;;                                   (string-append name "." ext)
+;;                                   name))
+;;            ((file hash) (test-file %store compressed-name "expected text")))
+;;         (call-with-temporary-directory
+;;          (lambda (dir)
+;;            (with-directory-excursion dir
+;;              (unpack #:source file)
+;;              (call-with-input-file name get-string-all))))))))
+;;  compressors)
+
 (test-end "builders")
diff --git a/tests/packages.scm b/tests/packages.scm
index a867f2fd6d..423485b68e 100644
--- a/tests/packages.scm
+++ b/tests/packages.scm
@@ -1,6 +1,7 @@ 
 ;;; GNU Guix --- Functional package management for GNU
 ;;; Copyright © 2012, 2013, 2014, 2015, 2016, 2017, 2018, 2019, 2020 Ludovic Courtès <ludo@gnu.org>
-;;; Copyright © Jan (janneke) Nieuwenhuizen <janneke@gnu.org>
+;;; Copyright © 2018 Jan (janneke) Nieuwenhuizen <janneke@gnu.org>
+;;; Copyright © 2021 Maxim Cournoyer <maxim.cournoyer@gmail.com>
 ;;;
 ;;; This file is part of GNU Guix.
 ;;;
@@ -17,12 +18,12 @@ 
 ;;; 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 (test-packages)
+(define-module (tests packages)
   #:use-module (guix tests)
   #:use-module (guix store)
   #:use-module (guix monads)
   #:use-module (guix grafts)
-  #:use-module ((guix gexp) #:select (local-file local-file-file))
+  #:use-module (guix gexp)
   #:use-module (guix utils)
   #:use-module ((guix diagnostics)
                 ;; Rename the 'location' binding to allow proper syntax
@@ -32,6 +33,7 @@ 
                                   (else name))))
   #:use-module ((gcrypt hash) #:prefix gcrypt:)
   #:use-module (guix derivations)
+  #:use-module (guix download)
   #:use-module (guix packages)
   #:use-module (guix grafts)
   #:use-module (guix search-paths)
@@ -50,6 +52,7 @@ 
   #:use-module (gnu packages version-control)
   #:use-module (gnu packages xml)
   #:use-module (srfi srfi-1)
+  #:use-module (srfi srfi-11)
   #:use-module (srfi srfi-26)
   #:use-module (srfi srfi-34)
   #:use-module (srfi srfi-35)
@@ -576,6 +579,11 @@ 
     (build-derivations %store (list drv))
     (call-with-input-file output get-string-all)))
 
+
+;;;
+;;; Source derivation with snippets.
+;;;
+
 (unless (network-reachable?) (test-skip 1))
 (test-equal "package-source-derivation, snippet"
   "OK"
@@ -631,6 +639,61 @@ 
     (and (build-derivations %store (list (pk 'snippet-drv drv)))
          (call-with-input-file out get-string-all))))
 
+;; Note: lzip is not part of bootstrap-coreutils&co, so is not included to
+;; avoid having to rebuild the world.
+(define compressors '(("gzip"  . "gz")
+                      ("xz"    . "xz")
+                      ("bzip2" . "bz2")
+                      (#f      . #f)))
+
+(for-each
+ (match-lambda
+   ((comp . ext)
+    (unless (network-reachable?) (test-skip 1))
+    (test-equal (string-append "origin->derivation, single file with snippet "
+                               "(compression: " (if comp comp "None") ")")
+      "2 + 2 = 4"
+      (let*-values
+          (((name) "maths")
+           ((compressed-name) (if comp
+                                  (string-append name "." ext)
+                                  name))
+           ((file hash) (test-file %store compressed-name "2 + 2 = 5"))
+           ;; Create an origin using the above computed file and its hash.
+           ((source) (origin
+                       (method url-fetch)
+                       (uri (string-append "file://" file))
+                       (file-name compressed-name)
+                       (patch-inputs `(("tar"   ,%bootstrap-coreutils&co)
+                                       ("xz"    ,%bootstrap-coreutils&co)
+                                       ("bzip2" ,%bootstrap-coreutils&co)
+                                       ("gzip"  ,%bootstrap-coreutils&co)))
+                       (patch-guile %bootstrap-guile)
+                       (modules '((guix build utils)))
+                       (snippet `(substitute* ,name
+                                   (("5") "4")))
+                       (hash (content-hash hash))))
+           ;; Build origin.
+           ((drv) (run-with-store %store (origin->derivation source)))
+           ((out) (derivation->output-path drv)))
+        ;; Decompress the resulting tar.xz and return its content.
+        (and (build-derivations %store (list drv))
+             (let* ((bin #~(string-append #+%bootstrap-coreutils&co
+                                          "/bin"))
+                    (f (computed-file
+                        name
+                        (with-imported-modules '((guix build utils))
+                          #~(begin
+                              (use-modules (guix build utils))
+                              (setenv "PATH" #+bin)
+                              (invoke "tar" "xvf" #+out)
+                              (copy-file #+name #$output)))))
+                    (drv (run-with-store %store (lower-object f)))
+                    (_ (build-derivations %store (list drv))))
+               (call-with-input-file (derivation->output-path drv)
+                 get-string-all)))))))
+ compressors)
+
 (test-assert "return value"
   (let ((drv (package-derivation %store (dummy-package "p"))))
     (and (derivation? drv)