build-system/pyproject: Ignore selected pytest inputs.

This commit includes squashed changes from
https://codeberg.org/guix/guix/pulls/7220 and
https://codeberg.org/guix/guix/pulls/7338.

* gnu/packages/aux-files/python/pytest_guix.py: New file.
* Makefile.am: Record it.
* guix/build/pyproject-build-system.scm (check): Preload pytest_guix
plugin when available.
* guix/build-system/pyproject.scm (default-pytest-guix-plugin): New
package, generated from pytest_guix.py.
(lower): Add python-pytest-guix argument, and inject it if
python-pytest is in the native-inputs.

Change-Id: I13263b461e9962aad340347657b9c9685db63927
Signed-off-by: Sharlatan Hellseher <sharlatanus@gmail.com>

4 files changed, 135 insertions, 12 deletions

diff --git a/Makefile.am b/Makefile.am
index 16ab2d317ec..79575c7dfdb 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -488,6 +488,7 @@ AUX_FILES =						\
   gnu/packages/aux-files/linux-libre/5.10-x86_64.conf   \
   gnu/packages/aux-files/ovmf/51-edk2-ovmf-2m-raw-x64-nosb.json \
   gnu/packages/aux-files/pack-audit.c                   \
+  gnu/packages/aux-files/python/pytest_guix.py          \
   gnu/packages/aux-files/python/sanity-check.py         \
   gnu/packages/aux-files/python/sitecustomize.py        \
   gnu/packages/aux-files/renpy/renpy.in \
diff --git a/gnu/packages/aux-files/python/pytest_guix.py b/gnu/packages/aux-files/python/pytest_guix.py
new file mode 100644
index 00000000000..750b1e99e99
--- /dev/null
+++ b/gnu/packages/aux-files/python/pytest_guix.py
@@ -0,0 +1,68 @@
+# GNU Guix --- Functional package management for GNU
+# Copyright © 2025 Nicolas Graves <ngraves@ngraves.fr>
+#
+# 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/>.
+
+import importlib.util
+
+
+def pytest_addoption(parser):
+    """Add stub options to be ignored by pytest.
+
+    More precisely, inject all options provided in .pytest_guix_options.json,
+    except options whose plugin is indeed installed.
+
+    For example, if the json file records --cov:
+      if the pytest_cov module is installed, its --cov will be used.
+      otherwise, --cov is ignored (read by this parser, but nothing is done
+      with it).
+
+    This allows to remove development packages, which are not required at build
+    time while at the same time avoiding the need to adjust test options in
+    pyproject.toml or other configuration files.
+    """
+    plugin_options = {
+        "cov": [
+            "--cov",
+            "--cov-reset",
+            "--cov-report",
+            "--cov-config",
+            "--no-cov-on-fail",
+            "--no-cov",
+            "--cov-fail-under",
+            "--cov-append",
+            "--cov-branch",
+            "--cov-context",
+        ],
+        "mypy": ["--mypy", "--mypy-config-file", "--mypy-ignore-missing-imports"],
+        "isort": ["--isort"],
+        "flake8": ["--flake8"],
+        "black": ["--black"],
+        "flakes": ["--flakes"],
+        "pep8": ["--pep8"],
+        "html": ["--html", "--self-contained-html", "--css"],
+    }
+
+    group = parser.getgroup(
+        "guix", "Options ignored by the Guix pyproject-build-system"
+    )
+
+    # Only add options for plugins that are not present.
+    for key, options in plugin_options.items():
+        if importlib.util.find_spec(f"pytest_{key}") is None:
+            # Plugin not found, add stub options
+            for option in options:
+                group.addoption(option, action="append", nargs="?")
diff --git a/guix/build-system/pyproject.scm b/guix/build-system/pyproject.scm
index d8939a7fde8..d833be10b47 100644
--- a/guix/build-system/pyproject.scm
+++ b/guix/build-system/pyproject.scm
@@ -23,15 +23,19 @@
   #:use-module (guix store)
   #:use-module (guix utils)
   #:use-module (guix gexp)
+  #:use-module ((guix licenses) #:prefix license:)
   #:use-module (guix monads)
   #:use-module (guix packages)
   #:use-module (guix search-paths)
   #:use-module (guix build-system)
   #:use-module (guix build-system gnu)
   #:use-module (guix build-system python)
+  #:use-module (guix build-system trivial)
   #:use-module (srfi srfi-1)
+  #:use-module (ice-9 match)
   #:export (%pyproject-build-system-modules
             default-python
+            default-pytest-guix-plugin
             default-sanity-check.py
             pyproject-build
             pyproject-build-system
@@ -62,6 +66,37 @@
   "Return the default guile-json package, resolved lazily."
   (@* (gnu packages guile) guile-json-4))
 
+;; Maybe try to upstream it at some point, it's currently flavored for guix
+;; but the idea itself is more general.
+(define (default-pytest-guix-plugin python)
+  (let* ((effective (version-major+minor (package-version python)))
+         (site (string-append "lib/python" effective "/site-packages/")))
+    (package
+      (name "python-pytest-guix")
+      (version "0.0.1")
+      (source (local-file (search-auxiliary-file "python/pytest_guix.py")))
+      (build-system trivial-build-system)
+      (arguments
+       (list
+        #:modules '((guix build utils))
+        #:builder
+        #~(begin
+            (use-modules (guix build utils))
+            (let* ((site (string-append #$output "/" #$site))
+                   (dist (string-append site "pytest_guix-" #$version
+                                        ".dist.info")))
+              (mkdir-p dist)
+              (copy-file #$source (string-append site "/pytest_guix.py"))
+              (call-with-output-file (string-append dist "/entry_points.txt")
+                (lambda (port)
+                  (format port "[pytest11]~%guix=pytest_guix~%")))))))
+      (home-page "https://guix.gnu.org/")
+      (synopsis "Ignore selected pytest options")
+      (description
+       "This package provides the script to cleanly ignore pytest options at the
+build-system level.")
+      (license license:gpl3+))))
+
 ;; TODO: On the next iteration of python-team, migrate the sanity-check to
 ;; importlib_metadata instead of setuptools.
 (define (default-sanity-check.py)
@@ -69,13 +104,21 @@
 
 (define* (lower name
                 #:key source inputs native-inputs outputs system target
+                test-backend
                 (python (default-python))
+                (python-pytest-guix (default-pytest-guix-plugin python))
                 (sanity-check.py (default-sanity-check.py))
                 #:allow-other-keys
                 #:rest arguments)
   "Return a bag for NAME."
   (define private-keywords
-    '(#:target #:python #:inputs #:native-inputs #:sanity-check.py))
+    '(#:target #:python #:inputs #:native-inputs
+      #:python-pytest-guix #:sanity-check.py))
+  (define native-inputs-labels (map car native-inputs))
+  (define has-pytest?
+    (or (member "python-pytest-bootstrap" native-inputs-labels)
+        (member "python-pytest" native-inputs-labels)))
+
 
   (and (not target)                               ;XXX: no cross-compilation
        (bag
@@ -88,9 +131,16 @@
 
                         ;; Keep the standard inputs of 'gnu-build-system'.
                         ,@(standard-packages)))
-         (build-inputs `(("python" ,python)
-                         ("sanity-check.py" ,sanity-check.py)
-                         ,@native-inputs))
+         (build-inputs
+          `(("python" ,python)
+            ("sanity-check.py" ,sanity-check.py)
+            ,@(if (and has-pytest?
+                       (match test-backend
+                         ((or 'pytest-with-guix-plugin #f) #t)
+                         (_ #f)))
+                  `(("python-pytest-guix" ,python-pytest-guix))
+                  `())
+            ,@native-inputs))
          (outputs (append outputs '(wheel)))
          (build pyproject-build)
          (arguments (strip-keyword-arguments private-keywords arguments)))))
diff --git a/guix/build/pyproject-build-system.scm b/guix/build/pyproject-build-system.scm
index 21f356c67e9..5685ddc033f 100644
--- a/guix/build/pyproject-build-system.scm
+++ b/guix/build/pyproject-build-system.scm
@@ -314,7 +314,7 @@ without errors."
     (with-directory-excursion "/tmp"
       (invoke "python" sanity-check.py (site-packages inputs outputs)))))
 
-(define* (check #:key tests? test-backend test-flags #:allow-other-keys)
+(define* (check #:key inputs tests? test-backend test-flags #:allow-other-keys)
   "Run the test suite of a given Python package."
   (if tests?
       ;; Unfortunately with PEP 517 there is no common method to specify test
@@ -330,20 +330,24 @@ without errors."
              (tests-found (find-files "." "test.*\\.py$"))
              (use-test-backend
               (or test-backend
-                  ;; Prefer pytest
-                  (if pytest 'pytest #f)
-                  (if stestr 'stestr #f)
-                  (if nosetests 'nose #f)
-                  (if nose2 'nose2 #f)
+                  ;; By order of preference.
+                  (and (assoc-ref inputs "python-pytest-guix")
+                       'pytest-with-guix-plugin)
+                  (and pytest 'pytest)
+                  (and stestr 'stestr)
+                  (and nosetests 'nose)
+                  (and nose2 'nose2)
                   ;; Fall back to setup.py. The command is deprecated, but is
                   ;; a superset of unittest, so should work for most packages.
                   ;; Keep it until setuptools removes `setup.py test'.
                   ;; See https://setuptools.pypa.io/en/latest/deprecated/\
                   ;; commands.html#test-build-package-and-run-a-unittest-suite
-                  (if have-setup-py 'setup.py #f)
-                  (if tests-found 'unittest #f))))
+                  (and have-setup-py 'setup.py)
+                  (and tests-found 'unittest))))
         (format #t "Using ~a~%" use-test-backend)
         (match use-test-backend
+          ('pytest-with-guix-plugin
+           (apply invoke pytest "-vv" "-p" "pytest_guix" test-flags))
           ('pytest
            (apply invoke pytest "-vv" test-flags))
           ('nose