i18n: adds a check on missing translation keys in locale/*.json file

This commit adds a script to check all keys from translation files to
make sure no missing keys / no translation files are incorrect.

Even if missing keys should not happen (because we use a script to add
keys automatically) this script made helped to understand that all
three `ar`, `eo` and `fr_FR` translation files were completly off
compared to the `en.json` file.

I believe we can safely delete `ar`, `eo` and `fr_FR` locales from
Zanata (because those languages are not set in the ALLOWED_LANGUAGES
config array). ⚠️ this needs to be check in the production `config.php`
file ⚠️.

Deleting the `fr_FR` locale file should solve both !358 and #395

closes !358 #395

.gitlab-ci.yml

@@ -17,6 +17,11 @@ test:
     paths:
       - vendor/
 
+check:missing:trads:
+  stage: test
+  script:
+    - ./scripts/check-translations.py
+
 # check-trad:
 #   stage: test
 #   allow_failure: true

scripts/check-translations.py

+#!/usr/bin/env python
+
+import json
+import glob
+
+def get_all_keys(jsons_dict):
+    all_keys = set()
+
+    for json_dict in jsons_dict.values():
+        all_keys |= flatten_keys(json_dict)
+
+    return all_keys
+
+def flatten_keys(json_dict):
+    all_keys = set()
+
+    for key in json_dict.keys():
+        el = json_dict[key]
+        if isinstance(el, dict):
+            flatten = flatten_keys(el)
+            for flat_key in flatten:
+                all_keys.add("%s.%s" % (key, flat_key))
+        else:
+            all_keys.add(key)
+
+    return all_keys
+
+def check_files_share_same_keys(all_keys, jsons):
+    exit_code = 0
+
+    for locale in jsons.keys():
+        difference = all_keys - flatten_keys(jsons[locale])
+        if bool(difference):
+            print("%s has missing translation keys:" % (locale))
+            for el in difference:
+                print("  - %s" % (el))
+            exit_code = 1
+
+    return exit_code
+
+def main():
+    locales_dir = "locale/*.json"
+
+    jsons = {}
+    for json_file in glob.iglob(locales_dir):
+        with open(json_file) as f:
+            jsons[json_file] = json.load(f)
+
+    all_keys = get_all_keys(jsons)
+
+    return check_files_share_same_keys(all_keys, jsons)
+
+main()