search-paths: Allow specs with #f as their separator.

This adds support for single-entry search paths.
Fixes <http://bugs.gnu.org/25422>.
Reported by Leo Famulari <leo@famulari.name>.

* guix/search-paths.scm (<search-path-specification>)[separator]:
Document as string or #f.
(evaluate-search-paths): Add case for SEPARATOR as #f.
(environment-variable-definition): Handle SEPARATOR being #f.
* guix/build/utils.scm (list->search-path-as-string): Add case for
SEPARATOR as #f.
(search-path-as-string->list): Likewise.
* guix/build/profiles.scm (abstract-profile): Likewise.
* tests/search-paths.scm: New file.
* Makefile.am (SCM_TESTS): Add it.
* tests/packages.scm ("--search-paths with single-item search path"):
New test.
* gnu/packages/version-control.scm (git)[native-search-paths](separator):
New field.

2 files changed, 96 insertions, 1 deletions

diff --git a/tests/packages.scm b/tests/packages.scm
index 247f75cc435..962f120ea2c 100644
--- a/tests/packages.scm
+++ b/tests/packages.scm
@@ -1,5 +1,5 @@
 ;;; GNU Guix --- Functional package management for GNU
-;;; Copyright © 2012, 2013, 2014, 2015, 2016 Ludovic Courtès <ludo@gnu.org>
+;;; Copyright © 2012, 2013, 2014, 2015, 2016, 2017 Ludovic Courtès <ludo@gnu.org>
 ;;;
 ;;; This file is part of GNU Guix.
 ;;;
@@ -42,6 +42,7 @@
   #:use-module (gnu packages base)
   #:use-module (gnu packages guile)
   #:use-module (gnu packages bootstrap)
+  #:use-module (gnu packages version-control)
   #:use-module (gnu packages xml)
   #:use-module (srfi srfi-1)
   #:use-module (srfi srfi-26)
@@ -979,6 +980,52 @@
                       (guix-package "-p" (derivation->output-path prof)
                                     "--search-paths"))))))
 
+(test-assert "--search-paths with single-item search path"
+  ;; Make sure 'guix package --search-paths' correctly reports environment
+  ;; variables for things like 'GIT_SSL_CAINFO' that have #f as their
+  ;; separator, meaning that the first match wins.
+  (let* ((p1 (dummy-package "foo"
+               (build-system trivial-build-system)
+               (arguments
+                `(#:guile ,%bootstrap-guile
+                  #:modules ((guix build utils))
+                  #:builder (begin
+                              (use-modules (guix build utils))
+                              (let ((out (assoc-ref %outputs "out")))
+                                (mkdir-p (string-append out "/etc/ssl/certs"))
+                                (call-with-output-file
+                                    (string-append
+                                     out "/etc/ssl/certs/ca-certificates.crt")
+                                  (const #t))))))))
+         (p2 (package (inherit p1) (name "bar")))
+         (p3 (dummy-package "git"
+               ;; Provide a fake Git to avoid building the real one.
+               (build-system trivial-build-system)
+               (arguments
+                `(#:guile ,%bootstrap-guile
+                  #:builder (mkdir (assoc-ref %outputs "out"))))
+               (native-search-paths (package-native-search-paths git))))
+         (prof1 (run-with-store %store
+                  (profile-derivation
+                   (packages->manifest (list p1 p3))
+                   #:hooks '()
+                   #:locales? #f)
+                  #:guile-for-build (%guile-for-build)))
+         (prof2 (run-with-store %store
+                  (profile-derivation
+                   (packages->manifest (list p2 p3))
+                   #:hooks '()
+                   #:locales? #f)
+                  #:guile-for-build (%guile-for-build))))
+    (build-derivations %store (list prof1 prof2))
+    (string-match (format #f "^export GIT_SSL_CAINFO=\"~a/etc/ssl/certs/ca-certificates.crt"
+                          (regexp-quote (derivation->output-path prof1)))
+                  (with-output-to-string
+                    (lambda ()
+                      (guix-package "-p" (derivation->output-path prof1)
+                                    "-p" (derivation->output-path prof2)
+                                    "--search-paths"))))))
+
 (test-equal "specification->package when not found"
   'quit
   (catch 'quit
diff --git a/tests/search-paths.scm b/tests/search-paths.scm
new file mode 100644
index 00000000000..2a4c18dd768
--- /dev/null
+++ b/tests/search-paths.scm
@@ -0,0 +1,48 @@
+;;; GNU Guix --- Functional package management for GNU
+;;; Copyright © 2017 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 (test-search-paths)
+  #:use-module (guix search-paths)
+  #:use-module (ice-9 match)
+  #:use-module (srfi srfi-64))
+
+(define %top-srcdir
+  (dirname (search-path %load-path "guix.scm")))
+
+
+(test-begin "search-paths")
+
+(test-equal "evaluate-search-paths, separator is #f"
+  (string-append %top-srcdir
+                 "/gnu/packages/bootstrap/armhf-linux")
+
+  ;; The following search path spec should evaluate to a single item: the
+  ;; first directory that matches the "-linux$" pattern in
+  ;; gnu/packages/bootstrap.
+  (let ((spec (search-path-specification
+               (variable "CHBOUIB")
+               (files '("gnu/packages/bootstrap"))
+               (file-type 'directory)
+               (separator #f)
+               (file-pattern "-linux$"))))
+    (match (evaluate-search-paths (list spec)
+                                  (list %top-srcdir))
+      (((spec* . value))
+       (and (eq? spec* spec) value)))))
+
+(test-end "search-paths")