Introduce the 'GUIX_PACKAGE_PATH' environment variable.

* gnu/packages.scm (%package-module-path): Honor $GUIX_PACKAGE_PATH.
* test-env.in: Unset 'GUIX_PACKAGE_PATH'.
* tests/guix-package.sh: Test it.
* doc/guix.texi (Package Modules): Document it.

1 files changed, 12 insertions, 1 deletions

diff --git a/gnu/packages.scm b/gnu/packages.scm
index ddabacd199..6d128280cc 100644
--- a/gnu/packages.scm
+++ b/gnu/packages.scm
@@ -91,7 +91,18 @@
   ;; Search path for package modules.  Each item must be either a directory
   ;; name or a pair whose car is a directory and whose cdr is a sub-directory
   ;; to narrow the search.
-  (list (cons %distro-root-directory "gnu/packages")))
+  (let* ((not-colon   (char-set-complement (char-set #\:)))
+         (environment (string-tokenize (or (getenv "GUIX_PACKAGE_PATH") "")
+                                       not-colon)))
+    ;; Automatically add items from $GUIX_PACKAGE_PATH to Guile's search path.
+    (for-each (lambda (directory)
+                (set! %load-path (cons directory %load-path))
+                (set! %load-compiled-path
+                      (cons directory %load-compiled-path)))
+              environment)
+
+    (make-parameter
+     (append environment `((,%distro-root-directory . "gnu/packages"))))))
 
 (define* (scheme-files directory)
   "Return the list of Scheme files found under DIRECTORY."