build/python: Add a sanity check phase.

Add a new phase validating the usability of installed Python packages.

* gnu/packages/aux-files/python/sanity-check.py: New file.
* Makefile.am (AUX_FILES): Register it.
* guix/build-system/python.scm (sanity-check.py): New variable.
(lower): Add the script as an implicit input.
* guix/build/python-build-system.scm: Remove trailing #t.
(sanity-check): New phase.
(%standard-phases): Use it.
* tests/builders.scm: (make-python-dummy)
(dummy-ok, dummy-dummy-nosetuptools, dummy-fail-requirements)
(dummy-fail-import, dummy-fail-console-script): New variables.
("python-build-system: dummy-ok")
("python-build-system: dummy-dummy-nosetuptools")
("python-build-system: dummy-fail-requirements")
("python-build-system: dummy-fail-import")
("python-build-system: dummy-fail-console-script"): Add tests.

5 files changed, 199 insertions, 13 deletions

diff --git a/Makefile.am b/Makefile.am
index 7ef8d4d61e..e60c5f4500 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -380,6 +380,7 @@ AUX_FILES =						\
   gnu/packages/aux-files/linux-libre/4.4-i686.conf	\
   gnu/packages/aux-files/linux-libre/4.4-x86_64.conf	\
   gnu/packages/aux-files/pack-audit.c			\
+  gnu/packages/aux-files/python/sanity-check.py		\
   gnu/packages/aux-files/python/sitecustomize.py	\
   gnu/packages/aux-files/run-in-namespace.c
 
diff --git a/gnu/packages/aux-files/python/sanity-check.py b/gnu/packages/aux-files/python/sanity-check.py
new file mode 100644
index 0000000000..355e55b240
--- /dev/null
+++ b/gnu/packages/aux-files/python/sanity-check.py
@@ -0,0 +1,91 @@
+# -*- coding: utf-8 -*-
+# GNU Guix --- Functional package management for GNU
+# Copyright © 2021 Lars-Dominik Braun <lars@6xq.net>
+#
+# 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/>.
+
+from __future__ import print_function  # Python 2 support.
+import importlib
+import pkg_resources
+import sys
+import traceback
+
+try:
+    from importlib.machinery import PathFinder
+except ImportError:
+    PathFinder = None
+
+ret = 0
+
+# Only check site-packages installed by this package, but not dependencies
+# (which pkg_resources.working_set would include). Path supplied via argv.
+ws = pkg_resources.find_distributions(sys.argv[1])
+
+for dist in ws:
+    print('validating', repr(dist.project_name), dist.location)
+    try:
+        print('...checking requirements: ', end='')
+        req = str(dist.as_requirement())
+        # dist.activate() is not enough to actually check requirements, we
+        # have to .require() it.
+        pkg_resources.require(req)
+        print('OK')
+    except Exception as e:
+        print('ERROR:', req, e)
+        ret = 1
+        continue
+
+    # Try to load top level modules. This should not have any side-effects.
+    try:
+        metalines = dist.get_metadata_lines('top_level.txt')
+    except KeyError:
+        # distutils (i.e. #:use-setuptools? #f) will not install any metadata.
+        print('WARNING: cannot determine top-level modules')
+        continue
+    for name in metalines:
+        # Only available on Python 3.
+        if PathFinder and PathFinder.find_spec(name) is None:
+            # Ignore unavailable modules, often C modules, which were not
+            # installed at the top-level. Cannot use ModuleNotFoundError,
+            # because it is raised by failed imports too.
+            continue
+        try:
+            print('...trying to load module', name, end=': ')
+            importlib.import_module(name)
+            print('OK')
+        except Exception:
+            print('ERROR:')
+            traceback.print_exc(file=sys.stdout)
+            ret = 1
+            continue
+
+    # Try to load entry points of console scripts too, making sure they
+    # work. They should be removed if they don't. Other groups may not be
+    # safe, as they can depend on optional packages.
+    for group, v in dist.get_entry_map().items():
+        if group not in {'console_scripts', 'gui_scripts'}:
+            continue
+        for name, ep in v.items():
+            try:
+                print('...trying to load endpoint', group, name, end=': ')
+                ep.load()
+                print('OK')
+            except Exception:
+                print('ERROR:')
+                traceback.print_exc(file=sys.stdout)
+                ret = 1
+
+sys.exit(ret)
diff --git a/guix/build-system/python.scm b/guix/build-system/python.scm
index e39c06528e..2bb6fa87ca 100644
--- a/guix/build-system/python.scm
+++ b/guix/build-system/python.scm
@@ -2,6 +2,7 @@
 ;;; Copyright © 2013, 2014, 2015, 2016, 2017 Ludovic Courtès <ludo@gnu.org>
 ;;; Copyright © 2013 Andreas Enge <andreas@enge.fr>
 ;;; Copyright © 2013 Nikita Karetnikov <nikita@karetnikov.org>
+;;; Copyright © 2021 Lars-Dominik Braun <lars@6xq.net>
 ;;;
 ;;; This file is part of GNU Guix.
 ;;;
@@ -19,6 +20,8 @@
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
 (define-module (guix build-system python)
+  #:use-module ((gnu packages) #:select (search-auxiliary-file))
+  #:use-module (guix gexp)
   #:use-module (guix store)
   #:use-module (guix utils)
   #:use-module (guix memoization)
@@ -70,6 +73,10 @@ extension, such as '.tar.gz'."
   (let ((python (resolve-interface '(gnu packages python))))
     (module-ref python 'python-2)))
 
+(define sanity-check.py
+  ;; The script used to validate the installation of a Python package.
+  (search-auxiliary-file "python/sanity-check.py"))
+
 (define* (package-with-explicit-python python old-prefix new-prefix
                                        #:key variant-property)
   "Return a procedure of one argument, P.  The procedure creates a package with
@@ -156,6 +163,7 @@ pre-defined variants."
                         ;; Keep the standard inputs of 'gnu-build-system'.
                         ,@(standard-packages)))
          (build-inputs `(("python" ,python)
+                         ("sanity-check.py" ,(local-file sanity-check.py))
                          ,@native-inputs))
          (outputs outputs)
          (build python-build)
diff --git a/guix/build/python-build-system.scm b/guix/build/python-build-system.scm
index 0f2402d3a3..1fc97d1398 100644
--- a/guix/build/python-build-system.scm
+++ b/guix/build/python-build-system.scm
@@ -9,6 +9,7 @@
 ;;; Copyright © 2019, 2020, 2021 Maxim Cournoyer <maxim.cournoyer@gmail.com>
 ;;; Copyright © 2020 Jakub Kądziołka <kuba@kadziolka.net>
 ;;; Copyright © 2020 Efraim Flashner <efraim@flashner.co.il>
+;;; Copyright © 2021 Lars-Dominik Braun <lars@6xq.net>
 ;;;
 ;;; This file is part of GNU Guix.
 ;;;
@@ -132,6 +133,15 @@
              (apply invoke "python" "./setup.py" command params)))
       (error "no setup.py found")))
 
+(define* (sanity-check #:key tests? inputs outputs #:allow-other-keys)
+  "Ensure packages depending on this package via setuptools work properly,
+their advertised endpoints work and their top level modules are importable
+without errors."
+  (let ((sanity-check.py (assoc-ref inputs "sanity-check.py")))
+    ;; Make sure the working directory is empty (i.e. no Python modules in it)
+    (with-directory-excursion "/tmp"
+      (invoke "python" sanity-check.py (site-packages inputs outputs)))))
+
 (define* (build #:key use-setuptools? #:allow-other-keys)
   "Build a given Python package."
   (call-setuppy "build" '() use-setuptools?)
@@ -209,8 +219,7 @@ running checks after installing the package."
     ;; '--invalidation-mode' option, do not generate any.
     (unless <3.7?
       (invoke "python" "-m" "compileall" "--invalidation-mode=unchecked-hash"
-              out))
-    #t))
+              out))))
 
 (define* (wrap #:key inputs outputs #:allow-other-keys)
   (define (list-of-files dir)
@@ -244,8 +253,7 @@ installed with setuptools."
          (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))
+      (rename-file easy-install-pth new-pth))))
 
 (define* (ensure-no-mtimes-pre-1980 #:rest _)
   "Ensure that there are no mtimes before 1980-01-02 in the source tree."
@@ -257,8 +265,7 @@ installed with setuptools."
     (ftw "." (lambda (file stat flag)
                (unless (<= early-1980 (stat:mtime stat))
                  (utime file early-1980 early-1980))
-               #t))
-    #t))
+               #t))))
 
 (define* (enable-bytecode-determinism #:rest _)
   "Improve determinism of pyc files."
@@ -266,8 +273,7 @@ installed with setuptools."
   (setenv "PYTHONHASHSEED" "0")
   ;; Prevent Python from creating .pyc files when loading modules (such as
   ;; when running a test suite).
-  (setenv "PYTHONDONTWRITEBYTECODE" "1")
-  #t)
+  (setenv "PYTHONDONTWRITEBYTECODE" "1"))
 
 (define* (ensure-no-cythonized-files #:rest _)
   "Check the source code for @code{.c} files which may have been pre-generated
@@ -278,8 +284,7 @@ by Cython."
               (string-append (string-drop-right file 3) "c")))
         (when (file-exists? generated-file)
           (format #t "Possible Cythonized file found: ~a~%" generated-file))))
-    (find-files "." "\\.pyx$"))
-  #t)
+    (find-files "." "\\.pyx$")))
 
 (define %standard-phases
   ;; The build phase only builds C extensions and copies the Python sources,
@@ -301,6 +306,7 @@ by Cython."
     (add-after 'install 'wrap wrap)
     (add-before 'check 'add-install-to-pythonpath add-install-to-pythonpath)
     (add-before 'check 'add-install-to-path add-install-to-path)
+    (add-after 'check 'sanity-check sanity-check)
     (add-before 'strip 'rename-pth-file rename-pth-file)))
 
 (define* (python-build #:key inputs (phases %standard-phases)
diff --git a/tests/builders.scm b/tests/builders.scm
index 624547500a..2143c0738b 100644
--- a/tests/builders.scm
+++ b/tests/builders.scm
@@ -1,5 +1,6 @@
 ;;; GNU Guix --- Functional package management for GNU
 ;;; Copyright © 2012, 2013, 2014, 2015, 2019 Ludovic Courtès <ludo@gnu.org>
+;;; Copyright © 2021 Lars-Dominik Braun <lars@6xq.net>
 ;;;
 ;;; This file is part of GNU Guix.
 ;;;
@@ -23,15 +24,15 @@
   #:use-module (guix build-system gnu)
   #:use-module (guix build gnu-build-system)
   #:use-module (guix build utils)
+  #:use-module (guix build-system python)
   #:use-module (guix store)
+  #:use-module (guix monads)
   #:use-module (guix utils)
   #:use-module (guix base32)
   #:use-module (guix derivations)
   #:use-module (gcrypt hash)
   #:use-module (guix tests)
-  #:use-module ((guix packages)
-                #:select (package?
-                          package-derivation package-native-search-paths))
+  #:use-module (guix packages)
   #:use-module (gnu packages bootstrap)
   #:use-module (ice-9 match)
   #:use-module (ice-9 textual-ports)
@@ -111,4 +112,83 @@
              (call-with-input-file name get-string-all))))))))
  compressors)
 
+
+;;;
+;;; Test the sanity-check phase of the Python build system.
+;;;
+
+(define* (make-python-dummy name #:key (setup-py-extra "")
+                            (init-py "") (use-setuptools? #t))
+  (dummy-package (string-append "python-dummy-" name)
+    (version "0.1")
+    (build-system python-build-system)
+    (arguments
+     `(#:tests? #f
+       #:use-setuptools? ,use-setuptools?
+       #:phases
+       (modify-phases %standard-phases
+         (replace 'unpack
+           (lambda _
+             (mkdir-p "dummy")
+             (with-output-to-file "dummy/__init__.py"
+               (lambda _
+                 (display ,init-py)))
+             (with-output-to-file "setup.py"
+               (lambda _
+                 (format #t "\
+~a
+setup(
+     name='dummy-~a',
+     version='0.1',
+     packages=['dummy'],
+     ~a
+     )"
+                         (if ,use-setuptools?
+                             "from setuptools import setup"
+                             "from distutils.core import setup")
+                         ,name ,setup-py-extra))))))))))
+
+(define python-dummy-ok
+  (make-python-dummy "ok"))
+
+;; distutil won't install any metadata, so make sure our script does not fail
+;; on a otherwise fine package.
+(define python-dummy-no-setuptools
+  (make-python-dummy
+   "no-setuptools" #:use-setuptools? #f))
+
+(define python-dummy-fail-requirements
+  (make-python-dummy "fail-requirements"
+                     #:setup-py-extra "install_requires=['nonexistent'],"))
+
+(define python-dummy-fail-import
+  (make-python-dummy "fail-import" #:init-py "import nonexistent"))
+
+(define python-dummy-fail-console-script
+  (make-python-dummy "fail-console-script"
+                     #:setup-py-extra (string-append "entry_points={'console_scripts': "
+                                                     "['broken = dummy:nonexistent']},")))
+
+(define (check-build-success store p)
+  (unless store (test-skip 1))
+  (test-assert (string-append "python-build-system: " (package-name p))
+    (let* ((drv (package-derivation store p)))
+      (build-derivations store (list drv)))))
+
+(define (check-build-failure store p)
+  (unless store (test-skip 1))
+  (test-assert (string-append "python-build-system: " (package-name p))
+    (not (false-if-exception (package-derivation store python-dummy-fail-requirements)))))
+
+(with-external-store store
+  (for-each (lambda (p) (check-build-success store p))
+            (list
+             python-dummy-ok
+             python-dummy-no-setuptools))
+  (for-each (lambda (p) (check-build-failure store p))
+            (list
+             python-dummy-fail-requirements
+             python-dummy-fail-import
+             python-dummy-fail-console-script)))
+
 (test-end "builders")