Add deeper XML checking to update-translation script

- Catch problems such as mismatched formatting characters. Remove
  messages that can give problems at runtime.

- Also remove unfinished/untranslated messages, they just take up space
  in the ts and waste parsing time.

Fixes #4774.

contrib/devtools/update-translations.py

@@ -14,13 +14,14 @@ It will do the following automatically:
 
 TODO:
 - auto-add new translations to the build system according to the translation process
-- remove 'unfinished' translation items
 '''
 from __future__ import division, print_function
 import subprocess
 import re
 import sys
 import os
+import io
+import xml.etree.ElementTree as ET
 
 # Name of transifex tool
 TX = 'tx'
@@ -40,24 +41,143 @@ def fetch_all_translations():
         print('Error while fetching translations', file=sys.stderr)
         exit(1)
 
-def postprocess_translations():
-    print('Postprocessing...')
+def find_format_specifiers(s):
+    '''Find all format specifiers in a string.'''
+    pos = 0
+    specifiers = []
+    while True:
+        percent = s.find('%', pos)
+        if percent < 0:
+            break
+        specifiers.append(s[percent+1])
+        pos = percent+2
+    return specifiers
+
+def split_format_specifiers(specifiers):
+    '''Split format specifiers between numeric (Qt) and others (strprintf)'''
+    numeric = []
+    other = []
+    for s in specifiers:
+        if s in {'1','2','3','4','5','6','7','8','9'}:
+            numeric.append(s)
+        else:
+            other.append(s)
+
+    # numeric (Qt) can be present in any order, others (strprintf) must be in specified order
+    return set(numeric),other
+
+def sanitize_string(s):
+    '''Sanitize string for printing'''
+    return s.replace('\n',' ')
+
+def check_format_specifiers(source, translation, errors):
+    source_f = split_format_specifiers(find_format_specifiers(source))
+    # assert that no source messages contain both Qt and strprintf format specifiers
+    # if this fails, go change the source as this is hacky and confusing!
+    assert(not(source_f[0] and source_f[1]))
+    try:
+        translation_f = split_format_specifiers(find_format_specifiers(translation))
+    except IndexError:
+        errors.append("Parse error in translation '%s'" % sanitize_string(translation))
+        return False
+    else:
+        if source_f != translation_f:
+            errors.append("Mismatch between '%s' and '%s'" % (sanitize_string(source), sanitize_string(translation)))
+            return False
+    return True
+
+def all_ts_files(suffix=''):
     for filename in os.listdir(LOCALE_DIR):
         # process only language files, and do not process source language
-        if not filename.endswith('.ts') or filename == SOURCE_LANG: 
+        if not filename.endswith('.ts'+suffix) or filename == SOURCE_LANG+suffix:
             continue
+        if suffix: # remove provided suffix
+            filename = filename[0:-len(suffix)]
         filepath = os.path.join(LOCALE_DIR, filename)
-        with open(filepath, 'rb') as f:
+        yield(filename, filepath)
+
+FIX_RE = re.compile(b'[\x00-\x09\x0b\x0c\x0e-\x1f]')
+def remove_invalid_characters(s):
+    '''Remove invalid characters from translation string'''
+    return FIX_RE.sub(b'', s)
+
+# Override cdata escape function to make our output match Qt's (optional, just for cleaner diffs for
+# comparison, disable by default)
+_orig_escape_cdata = None
+def escape_cdata(text):
+    text = _orig_escape_cdata(text)
+    text = text.replace("'", '&apos;')
+    text = text.replace('"', '&quot;')
+    return text
+
+def postprocess_translations(reduce_diff_hacks=False):
+    print('Checking and postprocessing...')
+
+    if reduce_diff_hacks:
+        global _orig_escape_cdata
+        _orig_escape_cdata = ET._escape_cdata
+        ET._escape_cdata = escape_cdata
+
+    for (filename,filepath) in all_ts_files():
+        os.rename(filepath, filepath+'.orig')
+
+    have_errors = False
+    for (filename,filepath) in all_ts_files('.orig'):
+        # pre-fixups to cope with transifex output
+        parser = ET.XMLParser(encoding='utf-8') # need to override encoding because 'utf8' is not understood only 'utf-8'
+        with open(filepath + '.orig', 'rb') as f:
             data = f.read()
-        # remove non-allowed control characters
-        data = re.sub('[\x00-\x09\x0b\x0c\x0e-\x1f]', '', data)
-        data = data.split('\n')
-        # strip locations from non-origin translation
-        # location tags are used to guide translators, they are not necessary for compilation
-        # TODO: actually process XML instead of relying on Transifex's one-tag-per-line output format
-        data = [line for line in data if not '<location' in line]
+        # remove control characters; this must be done over the entire file otherwise the XML parser will fail
+        data = remove_invalid_characters(data)
+        tree = ET.parse(io.BytesIO(data), parser=parser)
+
+        # iterate over all messages in file
+        root = tree.getroot()
+        for context in root.findall('context'):
+            for message in context.findall('message'):
+                numerus = message.get('numerus') == 'yes'
+                source = message.find('source').text
+                translation_node = message.find('translation')
+                # pick all numerusforms
+                if numerus:
+                    translations = [i.text for i in translation_node.findall('numerusform')]
+                else:
+                    translations = [translation_node.text]
+
+                for translation in translations:
+                    if translation is None:
+                        continue
+                    errors = []
+                    valid = check_format_specifiers(source, translation, errors)
+
+                    for error in errors:
+                        print('%s: %s' % (filename, error))
+
+                    if not valid: # set type to unfinished and clear string if invalid
+                        translation_node.clear()
+                        translation_node.set('type', 'unfinished')
+                        have_errors = True
+
+                # Remove location tags
+                for location in message.findall('location'):
+                    message.remove(location)
+
+                # Remove entire message if it is an unfinished translation
+                if translation_node.get('type') == 'unfinished':
+                    context.remove(message)
+
+        # write fixed-up tree
+        # if diff reduction requested, replace some XML to 'sanitize' to qt formatting
+        if reduce_diff_hacks:
+            out = io.BytesIO()
+            tree.write(out, encoding='utf-8')
+            out = out.getvalue()
+            out = out.replace(b' />', b'/>')
             with open(filepath, 'wb') as f:
-            f.write('\n'.join(data))
+                f.write(out)
+        else:
+            tree.write(filepath, encoding='utf-8')
+    return have_errors
 
 if __name__ == '__main__':
     check_at_repository_root()