Index: source/tools/i18n/checkTranslationsForSpam.py
===================================================================
--- source/tools/i18n/checkTranslationsForSpam.py
+++ source/tools/i18n/checkTranslationsForSpam.py
@@ -1,7 +1,7 @@
 #!/usr/bin/env python2
 # -*- coding:utf-8 -*-
 #
-# Copyright (C) 2014 Wildfire Games.
+# Copyright (C) 2018 Wildfire Games.
 # This file is part of 0 A.D.
 #
 # 0 A.D. is free software: you can redistribute it and/or modify
@@ -24,19 +24,20 @@
 from pology.catalog import Catalog
 from pology.message import Message
 
+# One can pass either a *.pot filename or a language from commandline
 
 l10nToolsDirectory = os.path.dirname(os.path.realpath(__file__))
 projectRootDirectory = os.path.abspath(os.path.join(l10nToolsDirectory, os.pardir, os.pardir, os.pardir))
 l10nFolderName = "l10n"
 
 
-def checkTranslationsForSpam(inputFilePath):
+def checkTranslations(inputFilePath, checkFilters):
 
-    print(u"Checking", inputFilePath)
+    print(u"Checking", os.path.basename(inputFilePath))
     templateCatalog = Catalog(inputFilePath)
 
     # If language codes were specified on the command line, filter by those.
-    filters = sys.argv[1:]
+    filters = sys.argv[1:] if checkFilters else ""
 
     # Load existing translation catalogs.
     existingTranslationCatalogs = []
@@ -52,6 +53,58 @@
                 if os.path.basename(inputFilePath)[:-4] == filename.split('.')[-2]:
                     existingTranslationCatalogs.append([filename[:-charactersToSkip], os.path.join(l10nFolderPath, filename)])
 
+    checkTranslationsForSprintfDefects(templateCatalog, existingTranslationCatalogs)
+    checkTranslationsForSpam(templateCatalog, existingTranslationCatalogs)
+
+def checkTranslationsForSprintfDefects(templateCatalog, existingTranslationCatalogs):
+
+    for languageCode, pofile in existingTranslationCatalogs:
+        translationCatalog = Catalog(pofile)
+        for templateMessage in templateCatalog:
+            checkTranslationForSprintfDefects(templateMessage, translationCatalog, pofile)
+
+def checkTranslationForSprintfDefects(templateMessage, translationCatalog, pofile):
+
+    # get translation
+    # this returns an empty list or a list with a single element, see
+    # http://pology.nedohodnik.net/doc/api/en_US/pology.catalog.Catalog-class.html#select_by_key
+    translationMessage = translationCatalog.select_by_key(templateMessage.msgctxt, templateMessage.msgid)
+    if not translationMessage:
+        return
+
+    # get sprintf arguments in the singular template
+    sprintfPattern = re.compile(u"%\([a-zA-Z0-9\-_]*\)s")
+
+    templateSprintfArgs = sprintfPattern.findall(templateMessage.msgid)
+
+    if templateMessage.msgid_plural:
+        templateSprintfArgs += sprintfPattern.findall(templateMessage.msgid_plural)
+
+    # Some sprintf translation comments mention sprintf arguments that are not used
+    # by the template string but can be used by the translaton
+    if templateMessage.auto_comment:
+        for comment in templateMessage.auto_comment:
+            templateSprintfArgs += sprintfPattern.findall(comment)
+
+    # assert that every sprintf argument in the translation is present in any of the template strings
+    for translationString in translationMessage[0].msgstr:
+        if not translationString:
+            return
+
+        translationSprintfArgs = sprintfPattern.findall(translationString)
+
+        for translationSprintfArg in translationSprintfArgs:
+            if translationSprintfArg not in templateSprintfArgs:
+                print(u"{}: The sprintf argument {} used by the translation “{}” isn't a present in the template string “{}” “{}”".format(
+                    os.path.basename(pofile),
+                    translationSprintfArg,
+                    translationString.replace("\n", "\\n"),
+                    templateMessage.msgid.replace("\n", "\\n"),
+                    templateMessage.msgid_plural.replace("\n", "\\n") if templateMessage.msgid_plural else ""))
+                # Show at most one error message per translation
+                return
+
+def checkTranslationsForSpam(templateCatalog, existingTranslationCatalogs):
     urlPattern = re.compile(u"http[s]?://(?:[a-zA-Z]|[0-9]|[$-_@.&+]|[!*\(\),]|(?:%[0-9a-fA-F][0-9a-fA-F]))+")
 
     # Check the URLs in translations against the URLs in the translation template.
@@ -60,7 +113,6 @@
         for templateMessage in templateCatalog:
             translationMessage = translationCatalog.select_by_key(templateMessage.msgctxt, templateMessage.msgid)
             if translationMessage:
-                templateSingularString = templateMessage.msgid
                 templateUrls = urlPattern.findall(templateMessage.msgid)
                 # Assert that the same URL is used in both the plural and singular forms.
                 if templateMessage.msgid_plural and len(templateMessage.msgstr) > 1:
@@ -75,22 +127,37 @@
                     for translationUrl in translationUrls:
                         if translationUrl not in templateUrls:
                             print(u"{}: Found the “{}” URL in the translation, which does not match any of the URLs in the translation template: {}".format(
-                                    languageCode,
+                                    os.path.basename(pofile),
                                     translationUrl,
                                     u", ".join(templateUrls)))
 
 
+def checkTranslationFile(fullPath, checkFilters):
+    try:
+        checkTranslations(fullPath, checkFilters)
+    except (KeyboardInterrupt, SystemExit):
+        sys.exit()
+    except:
+        raise
+
 def main():
 
     print(u"\n    WARNING: Remember to regenerate the POT files with “updateTemplates.py” before you run this script.\n    POT files are not in the repository.\n")
 
+    if len(sys.argv) > 1:
+        filePath = ' '.join(sys.argv[1:])
+        if os.path.isfile(filePath):
+            checkTranslationFile(filePath, False)
+            return
+
     foundPots = 0
     for root, folders, filenames in os.walk(projectRootDirectory):
         root = root.decode("utf-8")
         for filename in filenames:
             if len(filename) > 4 and filename[-4:] == ".pot" and os.path.basename(root) == "l10n":
                 foundPots += 1
-                checkTranslationsForSpam(os.path.join(root, filename))
+                checkTranslationFile(os.path.join(root, filename), True)
+
     if foundPots == 0:
         print(u"This script did not work because no ‘.pot’ files were found.")
         print(u"Please, run ‘updateTemplates.py’ to generate the ‘.pot’ files, and run ‘pullTranslations.py’ to pull the latest translations from Transifex.")