guix: build: Add transitive source building.

* guix/scripts/build.scm (%options, options->derivations): Add --sources
  option.
* doc/guix.texi (Invoking guix build): Document --sources option.
* tests/guix-build.sh: Add tests.

3 files changed, 163 insertions, 17 deletions

diff --git a/doc/guix.texi b/doc/guix.texi
index c68e2915d1..3328cbac91 100644
--- a/doc/guix.texi
+++ b/doc/guix.texi
@@ -2932,6 +2932,49 @@ The returned source tarball is the result of applying any patches and
 code snippets specified in the package's @code{origin} (@pxref{Defining
 Packages}).
 
+@item --sources
+Fetch and return the source of @var{package-or-derivation} and all their
+dependencies, recursively.  This is a handy way to obtain a local copy
+of all the source code needed to build @var{packages}, allowing you to
+eventually build them even without network access.  It is an extension
+of the @code{--source} option and can accept one of the following
+optional argument values:
+
+@table @code
+@item package
+This value causes the @code{--sources} option to behave in the same way
+as the @code{--source} option.
+
+@item all
+Build all packages' source derivations, including any source that might
+be listed as @code{inputs}.  This is the default value.
+
+@example
+$ guix build --sources tzdata
+The following derivations will be built:
+   /gnu/store/@dots{}-tzdata2015b.tar.gz.drv
+   /gnu/store/@dots{}-tzcode2015b.tar.gz.drv
+@end example
+
+@item transitive
+Build all packages' source derivations, as well as all source
+derivations for packages' transitive inputs.  This can be used e.g. to
+prefetch package source for later offline building.
+
+@example
+$ guix build --sources=transitive tzdata
+The following derivations will be built:
+   /gnu/store/@dots{}-tzcode2015b.tar.gz.drv
+   /gnu/store/@dots{}-findutils-4.4.2.tar.xz.drv
+   /gnu/store/@dots{}-grep-2.21.tar.xz.drv
+   /gnu/store/@dots{}-coreutils-8.23.tar.xz.drv
+   /gnu/store/@dots{}-make-4.1.tar.xz.drv
+   /gnu/store/@dots{}-bash-4.3.tar.xz.drv
+@dots{}
+@end example
+
+@end table
+
 @item --system=@var{system}
 @itemx -s @var{system}
 Attempt to build for @var{system}---e.g., @code{i686-linux}---instead of
diff --git a/guix/scripts/build.scm b/guix/scripts/build.scm
index 370c2a37ff..9366ab6ccc 100644
--- a/guix/scripts/build.scm
+++ b/guix/scripts/build.scm
@@ -228,6 +228,9 @@ Build the given PACKAGE-OR-DERIVATION and return their output paths.\n"))
   (display (_ "
   -S, --source           build the packages' source derivations"))
   (display (_ "
+  --sources[=TYPE]       build source derivations; TYPE may optionally be one
+                         of \"package\", \"all\" (default), or \"transitive\""))
+  (display (_ "
   -s, --system=SYSTEM    attempt to build for SYSTEM--e.g., \"i686-linux\""))
   (display (_ "
       --target=TRIPLET   cross-build for TRIPLET--e.g., \"armel-linux-gnu\""))
@@ -262,10 +265,22 @@ Build the given PACKAGE-OR-DERIVATION and return their output paths.\n"))
          (option '(#\V "version") #f #f
                  (lambda args
                    (show-version-and-exit "guix build")))
-
          (option '(#\S "source") #f #f
                  (lambda (opt name arg result)
-                   (alist-cons 'source? #t result)))
+                   (alist-cons 'source #t result)))
+         (option '("sources") #f #t
+                 (lambda (opt name arg result)
+                   (match arg
+                     ("package"
+                      (alist-cons 'source #t result))
+                     ((or "all" #f)
+                      (alist-cons 'source package-direct-sources result))
+                     ("transitive"
+                      (alist-cons 'source package-transitive-sources result))
+                     (else
+                      (leave (_ "invalid argument: '~a' option argument: ~a, ~
+must be one of 'package', 'all', or 'transitive'~%")
+                             name arg)))))
          (option '(#\s "system") #t #f
                  (lambda (opt name arg result)
                    (alist-cons 'system arg
@@ -308,28 +323,34 @@ build."
       (triplet
        (cut package-cross-derivation <> <> triplet <>))))
 
-  (define src?   (assoc-ref opts 'source?))
+  (define src    (assoc-ref opts 'source))
   (define sys    (assoc-ref opts 'system))
   (define graft? (assoc-ref opts 'graft?))
 
   (parameterize ((%graft? graft?))
     (let ((opts (options/with-source store
                                      (options/resolve-packages store opts))))
-      (filter-map (match-lambda
-                   (('argument . (? package? p))
-                    (if src?
+      (concatenate
+       (filter-map (match-lambda
+                    (('argument . (? package? p))
+                     (match src
+                       (#f
+                        (list (package->derivation store p sys)))
+                       (#t
                         (let ((s (package-source p)))
-                          (package-source-derivation store s))
-                        (package->derivation store p sys)))
-                   (('argument . (? derivation? drv))
-                    drv)
-                   (('argument . (? derivation-path? drv))
-                    (call-with-input-file drv read-derivation))
-                   (('argument . (? store-path?))
-                    ;; Nothing to do; maybe for --log-file.
-                    #f)
-                   (_ #f))
-                  opts))))
+                          (list (package-source-derivation store s))))
+                       (proc
+                        (map (cut package-source-derivation store <>)
+                             (proc p)))))
+                    (('argument . (? derivation? drv))
+                     (list drv))
+                    (('argument . (? derivation-path? drv))
+                     (list (call-with-input-file drv read-derivation)))
+                    (('argument . (? store-path?))
+                     ;; Nothing to do; maybe for --log-file.
+                     #f)
+                    (_ #f))
+                   opts)))))
 
 (define (options/resolve-packages store opts)
   "Return OPTS with package specification strings replaced by actual
diff --git a/tests/guix-build.sh b/tests/guix-build.sh
index 836c45e776..a72ce0911d 100644
--- a/tests/guix-build.sh
+++ b/tests/guix-build.sh
@@ -36,6 +36,88 @@ guix build -e '(@@ (gnu packages bootstrap) %bootstrap-guile)' |	\
 guix build hello -d |				\
     grep -e '-hello-[0-9\.]\+\.drv$'
 
+# Check --sources option with its arguments
+module_dir="t-guix-build-$$"
+mkdir "$module_dir"
+trap "rm -rf $module_dir" EXIT
+
+cat > "$module_dir/foo.scm"<<EOF
+(define-module (foo)
+  #:use-module (guix packages)
+  #:use-module (guix download)
+  #:use-module (guix build-system trivial))
+
+(define-public foo
+  (package
+    (name "foo")
+    (version "42")
+    (source (origin
+              (method url-fetch)
+              (uri "http://www.example.com/foo.tar.gz")
+              (sha256
+               (base32
+                "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx"))))
+    (build-system trivial-build-system)
+    (inputs
+     (quasiquote (("bar" ,bar))))
+    (home-page "www.example.com")
+    (synopsis "Dummy package")
+    (description "foo is a dummy package for testing.")
+    (license #f)))
+
+(define-public bar
+  (package
+    (name "bar")
+    (version "9001")
+    (source (origin
+              (method url-fetch)
+              (uri "http://www.example.com/bar.tar.gz")
+              (sha256
+               (base32
+                "yyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyy"))))
+    (build-system trivial-build-system)
+    (inputs
+     (quasiquote
+      (("data" ,(origin
+                 (method url-fetch)
+                 (uri "http://www.example.com/bar.dat")
+                 (sha256
+                  (base32
+                   "zzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzz")))))))
+    (home-page "www.example.com")
+    (synopsis "Dummy package")
+    (description "bar is a dummy package for testing.")
+    (license #f)))
+EOF
+
+GUIX_PACKAGE_PATH="$module_dir"
+export GUIX_PACKAGE_PATH
+
+# foo.tar.gz
+guix build -d -S foo
+guix build -d -S foo | grep -e 'foo\.tar\.gz'
+
+guix build -d --sources=package foo
+guix build -d --sources=package foo | grep -e 'foo\.tar\.gz'
+
+# bar.tar.gz and bar.dat
+guix build -d --sources bar
+test `guix build -d --sources bar \
+      | grep -e 'bar\.tar\.gz' -e 'bar\.dat' \
+      | wc -l` -eq 2
+
+# bar.tar.gz and bar.dat
+guix build -d --sources=all bar
+test `guix build -d --sources bar \
+      | grep -e 'bar\.tar\.gz' -e 'bar\.dat' \
+      | wc -l` -eq 2
+
+# Should include foo.tar.gz, bar.tar.gz, and bar.dat
+guix build -d --sources=transitive foo
+test `guix build -d --sources=transitive foo \
+      | grep -e 'foo\.tar\.gz' -e 'bar\.tar\.gz' -e 'bar\.dat' \
+      | wc -l` -eq 3
+
 # Should all return valid log files.
 drv="`guix build -d -e '(@@ (gnu packages bootstrap) %bootstrap-guile)'`"
 out="`guix build -e '(@@ (gnu packages bootstrap) %bootstrap-guile)'`"