Use tomllib from the standard library on Python 3.11+

Related: rhbz#2117571

macros.pyproject

@@ -143,7 +143,13 @@ echo 'python%{python3_pkgversion}-devel'
 echo 'python%{python3_pkgversion}dist(pip) >= 19'
 echo 'python%{python3_pkgversion}dist(packaging)'
 %{!-N:if [ -f pyproject.toml ]; then
-  echo 'python%{python3_pkgversion}dist(toml)'
+  %["%{python3_pkgversion}" == "3"
+    ? "echo '(python%{python3_pkgversion}dist(toml) if python%{python3_pkgversion}-devel < 3.11)'"
+    : "%[v"%{python3_pkgversion}" < v"3.11"
+       ? "echo 'python%{python3_pkgversion}dist(toml)'"
+       : "true # will use tomllib, echo nothing"
+    ]"
+  ]
 elif [ -f setup.py ]; then
   # Note: If the default requirements change, also change them in the script!
   echo 'python%{python3_pkgversion}dist(setuptools) >= 40.8'

pyproject-rpm-macros.spec

@@ -12,7 +12,7 @@ License:        MIT
 #   Increment Y and reset Z when new macros or features are added
 #   Increment Z when this is a bugfix or a cosmetic change
 # Dropping support for EOL Fedoras is *not* considered a breaking change
-Version:        1.2.0
+Version:        1.3.0
 Release:        1%{?dist}
 
 # Macro files
@@ -52,9 +52,9 @@ BuildRequires: python3dist(pyyaml)
 BuildRequires: python3dist(packaging)
 BuildRequires: python3dist(pip)
 BuildRequires: python3dist(setuptools)
-BuildRequires: python3dist(toml)
 BuildRequires: python3dist(tox-current-env) >= 0.0.6
 BuildRequires: python3dist(wheel)
+BuildRequires: (python3dist(toml) if python3-devel < 3.11)
 %endif
 
 # We build on top of those:
@@ -126,6 +126,9 @@ export HOSTNAME="rpmbuild"  # to speedup tox in network-less mock, see rhbz#1856
 %license LICENSE
 
 %changelog
+* Thu May 12 2022 Miro Hrončok <mhroncok@redhat.com> - 1.3.0-1
+- Use tomllib from the standard library on Python 3.11+
+
 * Wed Apr 27 2022 Miro Hrončok <mhroncok@redhat.com> - 1.2.0-1
 - %%pyproject_buildrequires: Add provisional -w flag for build backends without
   prepare_metadata_for_build_wheel hook

pyproject_buildrequires.py

@@ -187,21 +187,32 @@ class Requirements:
             self.add(req_str, **kwargs)
 
 
-def get_backend(requirements):
+def toml_load(opened_binary_file):
     try:
-        f = open('pyproject.toml')
-    except FileNotFoundError:
-        pyproject_data = {}
-    else:
+        # tomllib is in the standard library since 3.11.0b1
+        import tomllib as toml_module
+        load_from = opened_binary_file
+    except ImportError:
         try:
-            # lazy import toml here, not needed without pyproject.toml
-            import toml
+            # note: we could use tomli here,
+            # but for backwards compatibility with RHEL 9, we use toml instead
+            import toml as toml_module
+            load_from = io.TextIOWrapper(opened_binary_file, encoding='utf-8')
         except ImportError as e:
             print_err('Import error:', e)
             # already echoed by the %pyproject_buildrequires macro
             sys.exit(0)
+    return toml_module.load(load_from)
+
+
+def get_backend(requirements):
+    try:
+        f = open('pyproject.toml', 'rb')
+    except FileNotFoundError:
+        pyproject_data = {}
+    else:
         with f:
-            pyproject_data = toml.load(f)
+            pyproject_data = toml_load(f)
 
     buildsystem_data = pyproject_data.get('build-system', {})
     requirements.extend(