PR#4334: work around parse_qs behavior in python < 3.11

Merges #4334
https://pagure.io/koji/pull-request/4334

Fixes: #4332
https://pagure.io/koji/issue/4332
parse_qs fails on python 3.9

tests/test_www/loadwebindex.py

@@ -17,4 +17,4 @@ if importlib:
     sys.modules[INDEX_MOD] = webidx
     spec.loader.exec_module(webidx)
 else:
-    cli = imp.load_source(INDEX_MOD, INDEX_FILENAME)
+    webidx = imp.load_source(INDEX_MOD, INDEX_FILENAME)

tests/test_www/test_search.py

@@ -19,6 +19,7 @@ class TestSearch(unittest.TestCase):
         }
         urlencode_data = "terms=test&type=package&match=testmatch"
         self.fs = FieldStorageCompat({'QUERY_STRING': urlencode_data})
+        self.gen_html = mock.patch.object(webidx, '_genHTML').start()
 
         def __get_server(env):
             env['koji.form'] = self.fs
@@ -29,6 +30,18 @@ class TestSearch(unittest.TestCase):
     def tearDown(self):
         mock.patch.stopall()
 
+    def test_no_args(self):
+        self.fs = FieldStorageCompat({'QUERY_STRING': ''})
+
+        webidx.search(self.environ)
+
+        self.gen_html.assert_called_once()
+        # extract values
+        # called as _genHTML(environ, 'search.chtml')
+        args = self.gen_html.call_args_list[0][0]  # no kwargs passed here
+        environ = args[0]
+        self.assertEqual(environ['koji.values']['terms'], '')
+
     def test_search_exception_match(self):
         """Test taskinfo function raises exception"""
         self.server.getBuildTarget.return_info = None
@@ -37,3 +50,7 @@ class TestSearch(unittest.TestCase):
         with self.assertRaises(koji.GenericError) as cm:
             webidx.search(self.environ)
         self.assertEqual(str(cm.exception), "No such match type: 'testmatch'")
+        self.gen_html.assert_not_called()
+
+
+# the end

www/lib/kojiweb/util.py

@@ -211,8 +211,13 @@ class FieldStorageCompat(Mapping):
     """Emulate the parts of cgi.FieldStorage that we need"""
 
     def __init__(self, environ):
-        data = parse_qs(environ.get('QUERY_STRING', ''), strict_parsing=True,
-                        keep_blank_values=True)
+        qs = environ.get('QUERY_STRING', '')
+        if not qs:
+            # for python < 3.11, parse_qs will error on a blank string
+            self.data = {}
+            return
+
+        data = parse_qs(qs, strict_parsing=True, keep_blank_values=True)
         # replace singleton lists with single values
         for arg in data:
             val = data[arg]