Set %__python3 value according to %python3_pkgversion

I.e. when %python3_pkgversion is 3.12, %__python3 is /usr/bin/python3.12

We assume that when packagers package for Python 3.X, they want to change both
%python3_pkgversion and %__python3 value.

Hence instead of copy-pasting this:

    %global python3_pkgversion 3.X
    %global __python3 /usr/bin/python3.X

They just need to do:

    %global python3_pkgversion 3.X

Packagers who want to change the value of %__python3 without touching
%python3_pkgversion can still do it:

    %global __python3 /usr/bin/pypy3

Related: rhbz#1950291

macros.python-srpm

@@ -37,7 +37,7 @@
 
 # use the underscored macros to redefine the behavior of %%python3_version etc.
 %__python2 /usr/bin/python2
-%__python3 /usr/bin/python3
+%__python3 /usr/bin/python%{python3_pkgversion}
 
 # use the non-underscored macros to refer to Python in spec, etc.
 %python2 %__python2

python-rpm-macros.spec

@@ -1,6 +1,6 @@
 Name:           python-rpm-macros
 Version:        3.9
-Release:        46%{?dist}
+Release:        47%{?dist}
 Summary:        The common Python RPM macros
 URL:            https://src.fedoraproject.org/rpms/python-rpm-macros/
 
@@ -101,6 +101,10 @@ install -m 644 import_all_modules.py %{buildroot}%{_rpmconfigdir}/redhat/
 
 
 %changelog
+* Wed Dec 08 2021 Miro Hrončok <mhroncok@redhat.com> - 3.9-47
+- Set %%__python3 value according to %%python3_pkgversion
+  I.e. when %%python3_pkgversion is 3.12, %%__python3 is /usr/bin/python3.12
+
 * Mon Nov 01 2021 Karolina Surma <ksurma@redhat.com> - 3.9-46
 - Fix multiline arguments processing for %%py_check_import
 - Fix %%py_shebang_flags handling within %%py_check_import

tests/test_evals.py

@@ -83,6 +83,17 @@ def shell_stdout(script):
                                    shell=True).rstrip()
 
 
+@pytest.mark.parametrize('macro', ['%__python3', '%python3'])
+def test_python3(macro):
+    assert rpm_eval(macro) == ['/usr/bin/python3']
+
+
+@pytest.mark.parametrize('macro', ['%__python3', '%python3'])
+@pytest.mark.parametrize('pkgversion', ['3', '3.9', '3.12'])
+def test_python3_with_pkgversion(macro, pkgversion):
+    assert rpm_eval(macro, python3_pkgversion=pkgversion) == [f'/usr/bin/python{pkgversion}']
+
+
 @pytest.mark.parametrize('argument, result', [
     ('a', 'a'),
     ('a-a', 'a-a'),
@@ -629,7 +640,9 @@ def test_python3_sitelib_value_default():
 
 def test_python3_sitelib_value_alternate_python(alt_x_y):
     macro = '%python3_sitelib'
-    assert rpm_eval(macro, __python3=f'/usr/bin/python{alt_x_y}') == [f'/usr/lib/python{alt_x_y}/site-packages']
+    assert (rpm_eval(macro, __python3=f'/usr/bin/python{alt_x_y}') ==
+            rpm_eval(macro, python3_pkgversion=alt_x_y) ==
+            [f'/usr/lib/python{alt_x_y}/site-packages'])
 
 
 def test_python_sitearch_value_python3(lib):
@@ -649,7 +662,9 @@ def test_python3_sitearch_value_default(lib):
 
 def test_python3_sitearch_value_alternate_python(lib, alt_x_y):
     macro = '%python3_sitearch'
-    assert rpm_eval(macro, __python3=f'/usr/bin/python{alt_x_y}') == [f'/usr/{lib}/python{alt_x_y}/site-packages']
+    assert (rpm_eval(macro, __python3=f'/usr/bin/python{alt_x_y}') ==
+            rpm_eval(macro, python3_pkgversion=alt_x_y) ==
+            [f'/usr/{lib}/python{alt_x_y}/site-packages'])
 
 
 @pytest.mark.parametrize(