environment: For --ad-hoc, allow users to specify an output.

* guix/scripts/environment.scm (package+propagated-inputs): Add 'output'
  parameter.  Use it in return value.
  (options/resolve-packages): Use 'append-map' instead of 'map'.  For 'load'
  and 'expression', return all the outputs of the resulting package.  For
  'package', use 'specification->package+output' instead of
  'specification->package'.
  (guix-environment): Adjust uses of PACKAGES accordingly.
* doc/guix.texi (Invoking guix environment): Document it.
* tests/guix-environment.sh: Add test for --ad-hoc guile-bootstrap:out.

1 files changed, 3 insertions, 0 deletions

diff --git a/tests/guix-environment.sh b/tests/guix-environment.sh
index d04e6a6ea0..08c97cbb65 100644
--- a/tests/guix-environment.sh
+++ b/tests/guix-environment.sh
@@ -31,11 +31,14 @@ mkdir "$tmpdir"
 
 # Check the environment variables for the bootstrap Guile.
 guix environment --ad-hoc guile-bootstrap --pure --search-paths > "$tmpdir/a"
+guix environment --ad-hoc guile-bootstrap:out --pure --search-paths > "$tmpdir/b"
 
 # $PATH must appear in the search paths, and nothing else.
 grep -E '^export PATH=.*guile-bootstrap-[0-9.]+/bin' "$tmpdir/a"
 test "`wc -l < "$tmpdir/a"`" = 1
 
+cmp "$tmpdir/a" "$tmpdir/b"
+
 if guile -c '(getaddrinfo "www.gnu.org" "80" AI_NUMERICSERV)' 2> /dev/null
 then
     # Compute the build environment for the initial GNU Make.