gitlab-ci: check if Application ID will cause keyalias collision

fdroid/fdroidserver#553

.gitlab-ci.yml

@@ -37,4 +37,5 @@ lint:
     - echo "these images have EXIF that must be stripped:"
     - git --no-pager diff --stat
     - git --no-pager diff --name-only --exit-code || export EXITVALUE=1
+    - ./tools/check-keyalias-collision.py || export EXITVALUE=1
     - exit $EXITVALUE

tools/check-keyalias-collision.py

@@ -0,0 +1,30 @@
+#!/usr/bin/env python3
+
+import glob
+import hashlib
+import inspect
+import os
+import sys
+
+def generate_keyalias(s):
+    m = hashlib.md5()
+    m.update(s.encode())
+    return m.hexdigest()[:8]
+
+base = os.path.realpath(
+    os.path.join(os.path.dirname(inspect.getfile(inspect.currentframe())), '..'))
+metadatafiles = sorted(glob.glob(base + '/metadata/*.txt')
+                       + glob.glob(base + '/metadata/*.yml'))
+
+if not metadatafiles:
+    print('No metadata files found!')
+    sys.exit(1)
+
+keyaliases = dict()
+for f in metadatafiles:
+    appid = os.path.basename(f)[:-4]
+    keyalias = generate_keyalias(appid)
+    if keyalias in keyaliases:
+        print(appid, "keyalias conflicts with", keyaliases[keyalias])
+        sys.exit(1)
+    keyaliases[keyalias] = appid