Re: [PATCH 1/4] build/python-build-system: Fix easy-install.pth collisions.

[Federico Beffa <beffa@ieee.org>]

[-- Attachment #1: Type: text/plain, Size: 1861 bytes --]

On Sun, Dec 14, 2014 at 9:28 PM, Ludovic Courtès <ludo@gnu.org> wrote:
>> +(define* (fix-pth #:key name inputs outputs #:allow-other-keys)
>
> What about calling it ‘rename-pth-file’, which should be more
> descriptive?  Also please add a docstring.

Agreed.

>> +  (let* ((out (assoc-ref outputs "out"))
>> +         (python (assoc-ref inputs "python"))
>> +         (site-packages (string-append out "/lib/python"
>> +                                       (get-python-version python)
>> +                                       "/site-packages"))
>> +         (easy-install-pth (string-append site-packages "/easy-install.pth"))
>> +         (new-pth (string-append site-packages "/" name ".pth")))
>> +    (if (file-exists? easy-install-pth)
>> +        (rename-file easy-install-pth new-pth))))
>
> Please use ‘when’ instead of ‘if’, and add a trailing #t, to make it
> clear that the phase succeeds.

OK

> Is PACKAGE.pth a common convention?  I mean, does Python (or
> setuptools?) actually use files called PYTHON.pth?

Yes, the basename of path configuration files with extension .pth does
not matter. The site module will load them all. Setuptools, on top of
easy-install.pth, installs a site.py file. This program adds (with
site.addsitedir) all directories in PYTHONPATH to the list of
directories to be processed by the site module.

https://docs.python.org/2/library/site.html

Before writing the path I had conflicts, e.g., between matplotlib and
cairocffi resulting in import failures. After the patch they work
nicely together.

Using NAME.pth  instead of easy-install.pth should guarantee that no
package configuration file collisions occurs between different
packages installed with setuptools, nor between two versions of the
same library.

Attached the amended patch.
Regards,
Fede

[-- Attachment #2: 0001-build-python-build-system-Fix-easy-install.pth-colli.patch --]
[-- Type: text/x-patch, Size: 2338 bytes --]

From d32c6b5b51c4d61a2aef7467705073dafc1087d5 Mon Sep 17 00:00:00 2001
From: Federico Beffa <beffa@fbengineering.ch>
Date: Sat, 13 Dec 2014 22:19:08 +0100
Subject: [PATCH 1/4] build/python-build-system: Fix easy-install.pth
 collisions.

* guix/build/python-build-system.scm (rename-pth-file): New rename-pth-file
  phase and corresponding function.
---
 guix/build/python-build-system.scm | 35 ++++++++++++++++++++++++++---------
 1 file changed, 26 insertions(+), 9 deletions(-)

diff --git a/guix/build/python-build-system.scm b/guix/build/python-build-system.scm
index 2f3d04a..74ba0c7 100644
--- a/guix/build/python-build-system.scm
+++ b/guix/build/python-build-system.scm
@@ -105,19 +105,36 @@
                             files)))
               bindirs)))
 
+(define* (rename-pth-file #:key name inputs outputs #:allow-other-keys)
+  "Rename easy-install.pth to NAME.pth to avoid conflicts between packages
+installed with setuptools."
+  (let* ((out (assoc-ref outputs "out"))
+         (python (assoc-ref inputs "python"))
+         (site-packages (string-append out "/lib/python"
+                                       (get-python-version python)
+                                       "/site-packages"))
+         (easy-install-pth (string-append site-packages "/easy-install.pth"))
+         (new-pth (string-append site-packages "/" name ".pth")))
+    (when (file-exists? easy-install-pth)
+      (rename-file easy-install-pth new-pth))
+    #t))
+
 (define %standard-phases
   ;; 'configure' and 'build' phases are not needed.  Everything is done during
   ;; 'install'.
-  (alist-cons-after
-   'install 'wrap
-   wrap
-   (alist-replace
-    'build build
+  (alist-cons-before
+   'strip 'rename-pth-file
+   rename-pth-file
+   (alist-cons-after
+    'install 'wrap
+    wrap
     (alist-replace
-     'check check
-     (alist-replace 'install install
-                    (alist-delete 'configure
-                                               gnu:%standard-phases))))))
+     'build build
+     (alist-replace
+      'check check
+      (alist-replace 'install install
+                     (alist-delete 'configure
+                                   gnu:%standard-phases)))))))
 
 (define* (python-build #:key inputs (phases %standard-phases)
                        #:allow-other-keys #:rest args)
-- 
1.8.4