[bug#40469] [PATCH core-updates] build-system/python: Add a #:python-output argument.

[bug#40469] [PATCH core-updates] build-system/python: Add a #:python-output argument.

[Jakub Kądziołka]

This simplifies packages that ship Python bindings in a separate output.

* guix/build-system/python.scm (python-build): Add the argument, pass it
  build-side.
* guix/build/python-build-system.scm (site-packages): Add an #:output
  argument.
  (add-installed-pythonpath): Likewise.
  (install): Use the #:python-output argument.
  (wrap): Likewise.
  (rename-pth-file): Likewise. Use the site-packages procedure.
---

See #40267 for an example of what this change wants to accomplish.

 guix/build-system/python.scm       |  2 ++
 guix/build/python-build-system.scm | 27 ++++++++++++++-------------
 2 files changed, 16 insertions(+), 13 deletions(-)

diff --git a/guix/build-system/python.scm b/guix/build-system/python.scm
index e39c06528e..34cc487c8c 100644
--- a/guix/build-system/python.scm
+++ b/guix/build-system/python.scm
@@ -170,6 +170,7 @@ pre-defined variants."
                        (phases '(@ (guix build python-build-system)
                                    %standard-phases))
                        (outputs '("out"))
+                       (python-output "out")
                        (search-paths '())
                        (system (%current-system))
                        (guile #f)
@@ -196,6 +197,7 @@ provides a 'setup.py' file as its build system."
                      #:use-setuptools? ,use-setuptools?
                      #:phases ,phases
                      #:outputs %outputs
+                     #:python-output ,python-output
                      #:search-paths ',(map search-path-specification->sexp
                                            search-paths)
                      #:inputs %build-inputs)))
diff --git a/guix/build/python-build-system.scm b/guix/build/python-build-system.scm
index 09bd8465c8..3b19072264 100644
--- a/guix/build/python-build-system.scm
+++ b/guix/build/python-build-system.scm
@@ -154,28 +154,29 @@
          (major+minor (take components 2)))
     (string-join major+minor ".")))
 
-(define (site-packages inputs outputs)
+(define* (site-packages inputs outputs #:key (output "out"))
   "Return the path of the current output's Python site-package."
-  (let* ((out (assoc-ref outputs "out"))
+  (let* ((out (assoc-ref outputs output))
          (python (assoc-ref inputs "python")))
     (string-append out "/lib/python"
                    (python-version python)
                    "/site-packages/")))
 
-(define (add-installed-pythonpath inputs outputs)
+(define* (add-installed-pythonpath inputs outputs #:key (output "out"))
   "Prepend the Python site-package of OUTPUT to PYTHONPATH.  This is useful
 when running checks after installing the package."
   (let ((old-path (getenv "PYTHONPATH"))
-        (add-path (site-packages inputs outputs)))
+        (add-path (site-packages inputs outputs #:output output)))
     (setenv "PYTHONPATH"
             (string-append add-path
                            (if old-path (string-append ":" old-path) "")))
     #t))
 
 (define* (install #:key outputs (configure-flags '()) use-setuptools?
+                  (python-output "out")
                   #:allow-other-keys)
   "Install a given Python package."
-  (let* ((out (assoc-ref outputs "out"))
+  (let* ((out (assoc-ref outputs python-output))
          (params (append (list (string-append "--prefix=" out))
                          (if use-setuptools?
                              ;; distutils does not accept these flags
@@ -186,7 +187,9 @@ when running checks after installing the package."
     (call-setuppy "install" params use-setuptools?)
     #t))
 
-(define* (wrap #:key inputs outputs #:allow-other-keys)
+(define* (wrap #:key inputs outputs
+               (python-output "out")
+               #:allow-other-keys)
   (define (list-of-files dir)
     (find-files dir (lambda (file stat)
                       (and (eq? 'regular (stat:type stat))
@@ -199,7 +202,7 @@ when running checks after installing the package."
                         (string-append dir "/sbin"))))
                 outputs))
 
-  (let* ((out  (assoc-ref outputs "out"))
+  (let* ((out  (assoc-ref outputs python-output))
          (python (assoc-ref inputs "python"))
          (var `("PYTHONPATH" prefix
                 ,(cons (string-append out "/lib/python"
@@ -214,17 +217,15 @@ when running checks after installing the package."
               bindirs)
     #t))
 
-(define* (rename-pth-file #:key name inputs outputs #:allow-other-keys)
+(define* (rename-pth-file #:key name inputs outputs
+                          (python-output "out")
+                          #:allow-other-keys)
   "Rename easy-install.pth to NAME.pth to avoid conflicts between packages
 installed with setuptools."
   ;; Even if the "easy-install.pth" is not longer created, we kept this phase.
   ;; There still may be packages creating an "easy-install.pth" manually for
   ;; some good reason.
-  (let* ((out (assoc-ref outputs "out"))
-         (python (assoc-ref inputs "python"))
-         (site-packages (string-append out "/lib/python"
-                                       (python-version python)
-                                       "/site-packages"))
+  (let* ((site-packages (site-packages inputs outputs #:output python-output))
          (easy-install-pth (string-append site-packages "/easy-install.pth"))
          (new-pth (string-append site-packages "/" name ".pth")))
     (when (file-exists? easy-install-pth)
-- 
2.26.0

[bug#40469] [PATCH core-updates] build-system/python: Add a #:python-output argument.

[Leo Famulari]

On Mon, Apr 06, 2020 at 04:48:09PM +0200, Jakub Kądziołka wrote:
> This simplifies packages that ship Python bindings in a separate output.
> 
> * guix/build-system/python.scm (python-build): Add the argument, pass it
>   build-side.
> * guix/build/python-build-system.scm (site-packages): Add an #:output
>   argument.
>   (add-installed-pythonpath): Likewise.
>   (install): Use the #:python-output argument.
>   (wrap): Likewise.
>   (rename-pth-file): Likewise. Use the site-packages procedure.
> ---
> 
> See #40267 for an example of what this change wants to accomplish.

Too bad it didn't make it into the recent core-updates cycle.

If you are ready to add Unicorn, you could do that on master with a TODO
comment about using this feature once it is live.

And I think you can push this to the current core-updates along with a
commit adjusting Unicorn. If you cherry-picked just this commit to
master then it would probably not take *too* long to test. That's what I
would do to test it, anyways.

Thanks for working on this!

[bug#40469] [PATCH core-updates v2 1/2] build-system/python: Install to the python output if present.

[Jakub Kądziołka]

* gnu/build/python-build-system.scm (python-output): New procedure.
  (site-packages, install): Use python-output to find the output path.
  (wrap, rename-pth-file): Use site-packages where appropriate.
* doc/guix.texi (Build Systems): Mention the new behavior.
---

Following a discussion on IRC, I am changing the approach a bit. Also,
should this go on core-updates or staging? I'm not sure how to account
for all the dependent packages, but just grepping for
python-build-system puts this in the staging range.

$ rg python-build-system gnu/packages | wc -l
1474

 doc/guix.texi                      |  7 +++++++
 guix/build/python-build-system.scm | 24 +++++++++++-------------
 2 files changed, 18 insertions(+), 13 deletions(-)

diff --git a/doc/guix.texi b/doc/guix.texi
index 2268e159a2..7af98d3e00 100644
--- a/doc/guix.texi
+++ b/doc/guix.texi
@@ -6685,6 +6685,13 @@ By default guix calls @code{setup.py} under control of
 @code{setuptools}, much like @command{pip} does.  Some packages are not
 compatible with setuptools (and pip), thus you can disable this by
 setting the @code{#:use-setuptools?} parameter to @code{#f}.
+
+If a @code{"python"} output is available, the package is installed into it
+instead of the default @code{"out"} output. This is useful for packages that
+include a Python package as only a part of the software, and thus want to
+combine the phases of @code{python-build-system} with another build system.
+Python bindings are a common usecase.
+
 @end defvr
 
 @defvr {Scheme Variable} perl-build-system
diff --git a/guix/build/python-build-system.scm b/guix/build/python-build-system.scm
index 09bd8465c8..62e7a7b305 100644
--- a/guix/build/python-build-system.scm
+++ b/guix/build/python-build-system.scm
@@ -6,6 +6,7 @@
 ;;; Copyright © 2016 Hartmut Goebel <h.goebel@crazy-compilers.com>
 ;;; Copyright © 2018 Ricardo Wurmus <rekado@elephly.net>
 ;;; Copyright © 2018 Arun Isaac <arunisaac@systemreboot.net>
+;;; Copyright © 2020 Jakub Kądziołka <kuba@kadziolka.net>
 ;;;
 ;;; This file is part of GNU Guix.
 ;;;
@@ -154,9 +155,14 @@
          (major+minor (take components 2)))
     (string-join major+minor ".")))
 
+(define (python-output outputs)
+  "Return the path of the python output, if there is one, or fall-back to out."
+  (or (assoc-ref outputs "python")
+      (assoc-ref outputs "out")))
+
 (define (site-packages inputs outputs)
   "Return the path of the current output's Python site-package."
-  (let* ((out (assoc-ref outputs "out"))
+  (let* ((out (python-output outputs))
          (python (assoc-ref inputs "python")))
     (string-append out "/lib/python"
                    (python-version python)
@@ -175,7 +181,7 @@ when running checks after installing the package."
 (define* (install #:key outputs (configure-flags '()) use-setuptools?
                   #:allow-other-keys)
   "Install a given Python package."
-  (let* ((out (assoc-ref outputs "out"))
+  (let* ((out (python-output outputs))
          (params (append (list (string-append "--prefix=" out))
                          (if use-setuptools?
                              ;; distutils does not accept these flags
@@ -199,12 +205,8 @@ when running checks after installing the package."
                         (string-append dir "/sbin"))))
                 outputs))
 
-  (let* ((out  (assoc-ref outputs "out"))
-         (python (assoc-ref inputs "python"))
-         (var `("PYTHONPATH" prefix
-                ,(cons (string-append out "/lib/python"
-                                      (python-version python)
-                                      "/site-packages")
+  (let* ((var `("PYTHONPATH" prefix
+                ,(cons (site-packages inputs outputs)
                        (search-path-as-string->list
                         (or (getenv "PYTHONPATH") ""))))))
     (for-each (lambda (dir)
@@ -220,11 +222,7 @@ installed with setuptools."
   ;; Even if the "easy-install.pth" is not longer created, we kept this phase.
   ;; There still may be packages creating an "easy-install.pth" manually for
   ;; some good reason.
-  (let* ((out (assoc-ref outputs "out"))
-         (python (assoc-ref inputs "python"))
-         (site-packages (string-append out "/lib/python"
-                                       (python-version python)
-                                       "/site-packages"))
+  (let* ((site-packages (site-packages inputs outputs))
          (easy-install-pth (string-append site-packages "/easy-install.pth"))
          (new-pth (string-append site-packages "/" name ".pth")))
     (when (file-exists? easy-install-pth)
-- 
2.26.2

[bug#40469] [PATCH core-updates v2 2/2] gnu: unicorn: Use python-build-system with grace.

[Jakub Kądziołka]

* gnu/packages/emulators.scm (unicorn)[arguments]: Remove the
  install-bindings-to-python-output phase. Adjust output names used in
  other phases.
---
 gnu/packages/emulators.scm | 19 ++++---------------
 1 file changed, 4 insertions(+), 15 deletions(-)

diff --git a/gnu/packages/emulators.scm b/gnu/packages/emulators.scm
index ab5b662915..0e83d7e82c 100644
--- a/gnu/packages/emulators.scm
+++ b/gnu/packages/emulators.scm
@@ -1700,17 +1700,6 @@ performance, features, and ease of use.")
                     (guix build utils))
          #:phases
          (modify-phases %standard-phases
-           (add-after 'unpack 'install-bindings-to-python-output
-             (lambda* (#:key outputs #:allow-other-keys)
-               ;; python-build-system will build the bindings and install them to
-               ;; the "out" output, so change the build-internal names of the
-               ;; outputs.
-               ;;
-               ;; TODO: remove this once #40469 lands, through the core-updates
-               ;; holding zone, on master.
-               (set-car! (assoc "out" outputs) "lib")
-               (set-car! (assoc "python" outputs) "out")
-               #t))
            (add-before 'build 'build-library
              (lambda* (#:key inputs #:allow-other-keys)
                (invoke "make"
@@ -1723,7 +1712,7 @@ performance, features, and ease of use.")
                        "UNICORN_STATIC=no"
                        (string-append
                         "PREFIX="
-                        (assoc-ref outputs "lib")))))
+                        (assoc-ref outputs "out")))))
            (add-before 'build 'prepare-bindings
              (lambda* (#:key outputs #:allow-other-keys)
                (chdir "bindings/python")
@@ -1736,7 +1725,7 @@ performance, features, and ease of use.")
                  (("_path_list = \\[.*")
                   (string-append
                    "_path_list = [\""
-                   (assoc-ref outputs "lib")
+                   (assoc-ref outputs "out")
                    ;; eat the rest of the list
                    "/lib\"] + 0*[")))
                #t))
@@ -1757,10 +1746,10 @@ performance, features, and ease of use.")
                (let* ((python-samples (find-files "." "sample_.*"))
                       (c-samples (find-files "../../samples" ".*\\.c"))
                       (python-docdir
-                        (string-append (assoc-ref outputs "out")
+                        (string-append (assoc-ref outputs "python")
                                        "/share/doc/unicorn/samples"))
                       (c-docdir
-                        (string-append (assoc-ref outputs "lib")
+                        (string-append (assoc-ref outputs "out")
                                        "/share/doc/unicorn/samples")))
                  (for-each (cut install-file <> c-docdir) c-samples)
                  (for-each (cut install-file <> python-docdir) python-samples)
-- 
2.26.2

bug#40469: [PATCH core-updates] build-system/python: Add a #:python-output argument.

[Jakub Kądziołka]

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Patchstack pushed in commits @ 352e6c8a750c1b995ad8a357caf65eeded7e7774,
closing.

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