profiles: Add 'package->development-manifest'.

* guix/profiles.scm (package->development-manifest): New procedure.
* guix/scripts/environment.scm (input->manifest-entry)
(package-environment-inputs): Remove.
* guix/scripts/environment.scm (options/resolve-packages): Use
'package->development-manifest' instead of 'package-environment-inputs'.
* tests/profiles.scm ("package->development-manifest"): New test.

doc/guix.texi

@@ -3341,6 +3341,17 @@ objects, like this:
  '("emacs" "guile@@2.2" "guile@@2.2:debug"))
 @end lisp
 
+@findex package->development-manifest
+You might also want to create a manifest for all the dependencies of a
+package, rather than the package itself:
+
+@lisp
+(package->development-manifest (specification->package "emacs"))
+@end lisp
+
+The example above gives you all the software required to develop Emacs,
+similar to what @command{guix environment emacs} provides.
+
 @xref{export-manifest, @option{--export-manifest}}, to learn how to
 obtain a manifest file from an existing profile.
 

guix/profiles.scm

@@ -124,6 +124,7 @@
 
             profile-manifest
             package->manifest-entry
+            package->development-manifest
             packages->manifest
             ca-certificate-bundle
             %default-profile-hooks
@@ -400,6 +401,24 @@ file name."
                      (properties properties))))
     entry))
 
+(define* (package->development-manifest package
+                                        #:optional
+                                        (system (%current-system))
+                                        #:key target)
+  "Return a manifest for the \"development inputs\" of PACKAGE for SYSTEM,
+optionally when cross-compiling to TARGET.  Development inputs include both
+explicit and implicit inputs of PACKAGE."
+  (manifest
+   (filter-map (match-lambda
+                 ((label (? package? package))
+                  (package->manifest-entry package))
+                 ((label (? package? package) output)
+                  (package->manifest-entry package output))
+                 ;; TODO: Support <inferior-package>.
+                 (_
+                  #f))
+               (package-development-inputs package system #:target target))))
+
 (define (packages->manifest packages)
   "Return a list of manifest entries, one for each item listed in PACKAGES.
 Elements of PACKAGES can be either package objects or package/string tuples

guix/scripts/environment.scm

@@ -66,24 +66,6 @@ do not augment existing environment variables with additional search paths."
                (newline)))
             (profile-search-paths profile manifest)))
 
-(define (input->manifest-entry input)
-  "Return a manifest entry for INPUT, or #f if INPUT does not correspond to a
-package."
-  (match input
-    ((_ (? package? package))
-     (package->manifest-entry package))
-    ((_ (? package? package) output)
-     (package->manifest-entry package output))
-    (_
-     #f)))
-
-(define (package-environment-inputs package)
-  "Return a list of manifest entries corresponding to the transitive input
-packages for PACKAGE."
-  ;; Remove non-package inputs such as origin records.
-  (filter-map input->manifest-entry
-              (package-development-inputs package)))
-
 (define (show-help)
   (display (G_ "Usage: guix environment [OPTION]... PACKAGE... [-- COMMAND...]
 Build an environment that includes the dependencies of PACKAGE and execute
@@ -297,11 +279,11 @@ for the corresponding packages."
       ((? package? package)
        (if (eq? mode 'ad-hoc-package)
            (list (package->manifest-entry* package))
-           (package-environment-inputs package)))
+           (manifest-entries (package->development-manifest package))))
       (((? package? package) (? string? output))
        (if (eq? mode 'ad-hoc-package)
            (list (package->manifest-entry* package output))
-           (package-environment-inputs package)))
+           (manifest-entries (package->development-manifest package))))
       ((lst ...)
        (append-map (cut packages->outputs <> mode) lst))))
 
@@ -313,8 +295,9 @@ for the corresponding packages."
                                  (specification->package+output spec)))
                      (list (package->manifest-entry* package output))))
                   (('package 'package (? string? spec))
-                   (package-environment-inputs
-                    (transform (specification->package+output spec))))
+                   (manifest-entries
+                    (package->development-manifest
+                     (transform (specification->package+output spec)))))
                   (('expression mode str)
                    ;; Add all the outputs of the package STR evaluates to.
                    (packages->outputs (read/eval str) mode))

tests/profiles.scm

@@ -265,6 +265,13 @@
            (manifest-transaction-removal-candidate? guile-2.0.9 t)
            (null? install) (null? downgrade) (null? upgrade)))))
 
+(test-assert "package->development-manifest"
+  (let ((manifest (package->development-manifest packages:hello)))
+    (every (lambda (name)
+             (manifest-installed? manifest
+                                  (manifest-pattern (name name))))
+           '("gcc" "binutils" "glibc" "coreutils" "grep" "sed"))))
+
 (test-assertm "profile-derivation"
   (mlet* %store-monad
       ((entry ->   (package->manifest-entry %bootstrap-guile))