common: add calculate_gradle_flavor_combination

fdroidserver/common.py

@@ -58,6 +58,7 @@ from typing import List
 import git
 import glob
 import io
+import itertools
 import os
 import sys
 import re
@@ -4823,6 +4824,20 @@ def calculate_archive_policy(app, default):
     return archive_policy
 
 
+def calculate_gradle_flavor_combination(flavors):
+    """Calculate all combinations of gradle flavors."""
+    combination_lists = itertools.product(*[[flavor, ''] for flavor in flavors])
+    combinations = [
+        re.sub(
+            r' +\w',
+            lambda pat: pat.group(0)[-1].upper(),
+            ' '.join(combination_list).strip(),
+        )
+        for combination_list in combination_lists
+    ]
+    return combinations
+
+
 FDROIDORG_MIRRORS = [
     {
         'isPrimary': True,

tests/test_common.py

@@ -3040,6 +3040,11 @@ class CommonTest(SetUpTearDownMixin, unittest.TestCase):
         p = fdroidserver.common.FDroidPopen(['printenv', 'SOURCE_DATE_EPOCH'])
         self.assertEqual(int(p.output), int(now.timestamp()))
 
+    def test_calculate_gradle_flavor_combination(self):
+        flavors = ['aa', 'BB', 'δδ']
+        combinations = ['aaBBΔδ', 'aaBB', 'aaΔδ', 'aa', 'BBΔδ', 'BB', 'δδ', '']
+        self.assertEqual(fdroidserver.common.calculate_gradle_flavor_combination(flavors), combinations)
+
 
 APKS_WITH_JAR_SIGNATURES = (
     (