Add a tool to check printf style format string in translations (#48530)

* Add script to check printf format string in translation

* Coloured output and highlighted diagnostic message

* Add GitHub Action workflow to check printf format string in translations

.github/workflows/check-translation.yml

@@ -0,0 +1,21 @@
+name: Check printf format string in translations
+
+on:
+  pull_request:
+    paths:
+      - 'lang/po/*.po'
+      - 'tools/check_po_printf_format.py'
+
+jobs:
+  check-po-printf:
+    runs-on: ubuntu-20.04
+    steps:
+      - name: "Install dependencies"
+        run: |
+          sudo apt-get update
+          sudo apt-get install python3-pip
+          sudo pip3 install polib
+      - name: "Checkout"
+        uses: actions/checkout@v2
+      - name: "Check printf format string in translations"
+        run: ./tools/check_po_printf_format.py

tools/check_po_printf_format.py

@@ -0,0 +1,142 @@
+#!/usr/bin/env python3
+import polib
+import os
+import re
+types = ["d", "i", "u", "f", "e", "g", "x", "s", "c", "p"]
+
+
+def findall(p, s):
+    i = s.find(p)
+    while i != -1:
+        yield i
+        i = s.find(p, i + 1)
+
+
+def is_formatted_entry(msg):
+    if "%" not in msg:
+        return False
+    indices = list(findall("%", msg))
+    index_iter = iter(indices)
+    for i in index_iter:
+        if i + 1 == len(msg):
+            return False
+        if msg[i + 1] == "%":  # skip %%
+            next(index_iter, None)
+            continue
+        if not msg[i + 1].isnumeric() and \
+           msg[i + 1] not in ["d", "s", "c", "l", "f", "."]:
+            return False
+        if msg[i + 1] == "." and \
+           (i + 2 == len(msg) or not msg[i + 2].isnumeric()):
+            return False
+    return True
+
+
+def decompose_format_strings(msg):
+    indices = list(findall("%", msg))
+    non_positional = []
+    positional = []
+    segments = []
+    index_iter = iter(indices)
+    for i in index_iter:
+        if i + 1 == len(msg):
+            break
+        if msg[i + 1] == "%":  # skip %%
+            next(index_iter, None)
+            continue
+        if msg[i + 1].isnumeric() and msg[i + 2] == "$":
+            # positional format strings %1$s, %2$d, etc.
+            positional.append(msg[i:i + 4])
+            segments.append((i, i + 4))
+        else:
+            # non-positional format strings %s, %3d, etc.
+            idx = i + 1
+            while msg[idx] not in types and idx + 1 < len(msg):
+                idx += 1
+            if idx == len(msg):
+                break
+            # ignore the cases where "%d" is translated to "%2d"
+            non_positional.append(re.sub(r'[0-9]+', '', msg[i:idx + 1]))
+            segments.append((i, idx + 1))
+    return (non_positional, positional, segments)
+
+
+def check_message(entry):
+    msgid = entry.msgid
+    msgstr = entry.msgstr
+    if not is_formatted_entry(msgid) and not is_formatted_entry(msgstr):
+        return (True, [], [])
+    (non_pos_msgid, pos_msgid, seg_msgid) = decompose_format_strings(msgid)
+    (non_pos_msgstr, pos_msgstr, seg_msgstr) = decompose_format_strings(msgstr)
+    if non_pos_msgid == non_pos_msgstr and \
+       sorted(pos_msgid) == sorted(pos_msgstr):
+        return (True, [], [])
+    # Allow "%1$s %2$d" translated to "%s %d"
+    # as long as the order of types is preserved
+    if len(non_pos_msgid) == 0 and len(pos_msgid) > 0 and \
+       len(non_pos_msgstr) == len(pos_msgid) and len(pos_msgstr) == 0:
+        for i in range(len(pos_msgid)):
+            if pos_msgid[i][-1] != non_pos_msgstr[i][-1]:
+                return (False, seg_msgid, seg_msgstr)
+        return (True, [], [])
+    # otherwise it's an error
+    return (False, seg_msgid, seg_msgstr)
+
+
+def check_po_file(file):
+    pofile = polib.pofile(file)
+    errors = []
+    for entry in pofile.translated_entries():
+        if entry.msgid_plural:
+            # TODO: implement proper check for plural messages
+            continue
+        (ok, seg_msgid, seg_msgstr) = check_message(entry)
+        if not ok:
+            errors.append((entry.msgid, entry.msgstr, seg_msgid, seg_msgstr))
+    return errors
+
+
+class bcolors:
+    HEADER = '\033[95m'
+    OKBLUE = '\033[94m'
+    OKCYAN = '\033[96m'
+    OKGREEN = '\033[92m'
+    WARNING = '\033[93m'
+    FAIL = '\033[91m'
+    ENDC = '\033[0m'
+    BOLD = '\033[1m'
+    UNDERLINE = '\033[4m'
+
+
+def print_message(msg, segments):
+    beg = [x for (x, y) in segments]
+    end = [y for (x, y) in segments]
+    for i in range(len(msg)):
+        if i in beg:
+            print(bcolors.FAIL, end="")
+            print(bcolors.UNDERLINE, end="")
+        elif i in end:
+            print(bcolors.ENDC, end="")
+        print(msg[i], end="")
+    print()
+
+
+num_errors = 0
+for file in sorted(os.listdir("lang/po")):
+    if file.endswith(".po") and not file.endswith("en.po"):
+        print("Checking", file, end="", flush=True)
+        errors = check_po_file("lang/po/" + file)
+        n = len(errors)
+        num_errors += n
+        if n > 0:
+            print(f" => {bcolors.FAIL}{n} error(s) detected:{bcolors.ENDC}")
+            for (msgid, msgstr, seg_msgid, seg_msgstr) in errors:
+                print(f"{bcolors.BOLD}original  :{bcolors.ENDC}", end="")
+                print_message(msgid.replace("\n\n", "\n"), seg_msgid)
+                print(f"{bcolors.BOLD}translated:{bcolors.ENDC}", end="")
+                print_message(msgstr.replace("\n\n", "\n"), seg_msgstr)
+                print()
+        else:
+            print(f" => {bcolors.OKGREEN}No error detected.{bcolors.ENDC}")
+        print()
+exit(num_errors)