Automatically word-wrap the description of extras subpackages

This only works for package and extra names less than 79 characters long.
I don't expect many actual packages to exceed this limit.
78 characters should be enough for everybody.

Why 78? 79 is the line-lenght limit from rpmlint.
And we need to put punctuation in there.

macros.python-srpm

@@ -202,8 +202,18 @@
         local rpmname = value_n .. '+' .. extras
         local pkgdef = '%package -n ' .. rpmname
         local summary = 'Summary: Metapackage for ' .. value_n .. ': ' .. extras .. ' extras'
-        local description = '%description -n ' .. rpmname .. '\\\n' ..
+        local description = '%description -n ' .. rpmname .. '\\\n'
-                            'This is a metapackage bringing in ' .. extras .. ' extras requires for ' .. value_n .. '.\\\n' ..
+        local current_line = 'This is a metapackage bringing in'
+        for _, word in ipairs({extras, 'extras', 'requires', 'for', value_n .. '.'}) do
+          local line = current_line .. ' ' .. word
+          if line:len() > 79 then
+            description = description .. current_line .. '\\\n'
+            current_line = word
+          else
+            current_line = line
+          end
+        end
+        description = description .. current_line .. '\\\n' ..
                       'It contains no code, just makes sure the dependencies are installed.\\\n'
         local files = ''
         if value_i ~= '' then

python-rpm-macros.spec

@@ -1,6 +1,6 @@
 Name:           python-rpm-macros
 Version:        3.9
-Release:        12%{?dist}
+Release:        13%{?dist}
 Summary:        The common Python RPM macros
 
 # macros and lua: MIT, compileall2.py: PSFv2
@@ -107,6 +107,10 @@ install -m 644 compileall2.py %{buildroot}%{_rpmconfigdir}/redhat/
 
 
 %changelog
+* Fri Feb 05 2021 Miro Hrončok <mhroncok@redhat.com> - 3.9-13
+- Automatically word-wrap the description of extras subpackages
+- Fixes: rhbz#1922442
+
 * Wed Jan 27 2021 Fedora Release Engineering <releng@fedoraproject.org> - 3.9-12
 - Rebuilt for https://fedoraproject.org/wiki/Fedora_34_Mass_Rebuild
 

tests/test_evals.py

@@ -340,7 +340,8 @@ def test_python_extras_subpkg_i():
         Summary: Metapackage for python3-setuptools_scm: toml extras
         Requires: python3-setuptools_scm = 6-7
         %description -n python3-setuptools_scm+toml
-        This is a metapackage bringing in toml extras requires for python3-setuptools_scm.
+        This is a metapackage bringing in toml extras requires for
+        python3-setuptools_scm.
         It contains no code, just makes sure the dependencies are installed.
 
         %files -n python3-setuptools_scm+toml
@@ -350,7 +351,8 @@ def test_python_extras_subpkg_i():
         Summary: Metapackage for python3-setuptools_scm: yaml extras
         Requires: python3-setuptools_scm = 6-7
         %description -n python3-setuptools_scm+yaml
-        This is a metapackage bringing in yaml extras requires for python3-setuptools_scm.
+        This is a metapackage bringing in yaml extras requires for
+        python3-setuptools_scm.
         It contains no code, just makes sure the dependencies are installed.
 
         %files -n python3-setuptools_scm+yaml
@@ -367,7 +369,8 @@ def test_python_extras_subpkg_f():
         Summary: Metapackage for python3-setuptools_scm: toml extras
         Requires: python3-setuptools_scm = 6-7
         %description -n python3-setuptools_scm+toml
-        This is a metapackage bringing in toml extras requires for python3-setuptools_scm.
+        This is a metapackage bringing in toml extras requires for
+        python3-setuptools_scm.
         It contains no code, just makes sure the dependencies are installed.
 
         %files -n python3-setuptools_scm+toml -f ghost_filelist
@@ -376,7 +379,8 @@ def test_python_extras_subpkg_f():
         Summary: Metapackage for python3-setuptools_scm: yaml extras
         Requires: python3-setuptools_scm = 6-7
         %description -n python3-setuptools_scm+yaml
-        This is a metapackage bringing in yaml extras requires for python3-setuptools_scm.
+        This is a metapackage bringing in yaml extras requires for
+        python3-setuptools_scm.
         It contains no code, just makes sure the dependencies are installed.
 
         %files -n python3-setuptools_scm+yaml -f ghost_filelist
@@ -392,7 +396,8 @@ def test_python_extras_subpkg_F():
         Summary: Metapackage for python3-setuptools_scm: toml extras
         Requires: python3-setuptools_scm = 6-7
         %description -n python3-setuptools_scm+toml
-        This is a metapackage bringing in toml extras requires for python3-setuptools_scm.
+        This is a metapackage bringing in toml extras requires for
+        python3-setuptools_scm.
         It contains no code, just makes sure the dependencies are installed.
 
 
@@ -401,12 +406,35 @@ def test_python_extras_subpkg_F():
         Summary: Metapackage for python3-setuptools_scm: yaml extras
         Requires: python3-setuptools_scm = 6-7
         %description -n python3-setuptools_scm+yaml
-        This is a metapackage bringing in yaml extras requires for python3-setuptools_scm.
+        This is a metapackage bringing in yaml extras requires for
+        python3-setuptools_scm.
         It contains no code, just makes sure the dependencies are installed.
         """).lstrip().splitlines()
     assert lines == expected
 
 
+@pytest.mark.parametrize('basename_len', [1, 10, 30, 45, 78])
+@pytest.mark.parametrize('extra_len', [1, 13, 28, 52, 78])
+def test_python_extras_subpkg_description_wrapping(basename_len, extra_len):
+    basename = 'x' * basename_len
+    extra = 'y' * extra_len
+    lines = rpm_eval(f'%python_extras_subpkg -n {basename} -F {extra}',
+                     version='6', release='7')
+    for idx, line in enumerate(lines):
+        if line.startswith('%description'):
+            start = idx + 1
+    lines = lines[start:]
+    assert all(len(l) < 80 for l in lines)
+    assert len(lines) < 6
+    if len(" ".join(lines[:-1])) < 80:
+        assert len(lines) == 2
+    expected_singleline = (f"This is a metapackage bringing in {extra} extras "
+                           f"requires for {basename}. It contains no code, "
+                           f"just makes sure the dependencies are installed.")
+    description_singleline = " ".join(lines)
+    assert description_singleline == expected_singleline
+
+
 unversioned_macros = pytest.mark.parametrize('macro', [
     '%__python',
     '%python',