mask: improve parsing of empty header line

If the header of mask had a break, which looked like `#`, it would fail
to parse, which is somewhat wrong. So add it as exception.

Signed-off-by: Arthur Zamarin <arthurzam@gentoo.org>

Author: arthurzam

src/pkgdev/scripts/pkgdev_mask.py

@@ -160,7 +160,7 @@ def parse(self):
             comment = []
             i = mask_lines[0] - 2
             while i >= 0 and (line := lines[i].rstrip()):
-                if not line.startswith('# '):
+                if not line.startswith('# ') and line != '#':
                     mask.error(f'invalid mask entry header, lineno {i + 1}: {line!r}')
                 comment.append(line[2:])
                 i -= 1
@@ -274,8 +274,7 @@ def _mask(options, out, err):
 
     if options.rites:
         removal_date = today + timedelta(days=options.rites)
-        removal = removal_date.strftime('%Y-%m-%d')
-        mask_args['comment'].append(f'Removal: {removal}')
+        mask_args['comment'].append(f'Removal: {removal_date:%Y-%m-%d}')
 
     m = Mask(**mask_args)
     mask_file.add(m)

tests/scripts/test_pkgdev_mask.py

@@ -194,6 +194,29 @@ def test_existing_masks(self):
             self.script()
         assert self.profile.masks == frozenset([atom_cls('cat/masked'), atom_cls('=cat/pkg-0')])
 
+    def test_invalid_header(self, capsys):
+        self.masks_path.write_text(textwrap.dedent("""\
+            # Random Dev <random.dev@email.com> (2022-09-09)
+            #
+            # Larry the Cow was here
+            #
+            # masked
+            cat/masked
+
+            # Larry the Cow <larry@gentoo.org> (2022-09-09)
+            #test
+            # Larry the Cow wasn't here
+            cat/masked2
+        """))
+
+        with os_environ(EDITOR="sed -i '1s/$/mask comment/'"), \
+                patch('sys.argv', self.args + ['=cat/pkg-0']), \
+                pytest.raises(SystemExit), \
+                chdir(pjoin(self.repo.path)):
+            self.script()
+        _, err = capsys.readouterr()
+        assert 'invalid mask entry header, lineno 9' in err
+
     def test_invalid_author(self, capsys):
         for line in (
             '# Random Dev <random.dev@email.com>',