Translatable strings using %r and %s cause problems if translation reverses order

[jfbu]

On master branch (at circa 14-11-2019 16:42:29 CET for transifex pull)

cd sphinx/locale
tx pull -f -a
cd ../..
python setup.py compile_catalog

output (trimmed)

running compile_catalog
...
error: sphinx/locale/ja/LC_MESSAGES/sphinx.po:1280: positional format placeholders are unbalanced
error: sphinx/locale/ja/LC_MESSAGES/sphinx.po:2415: incompatible format for placeholder 1: 'r' and 's' are not compatible
...
error: sphinx/locale/zh_CN/LC_MESSAGES/sphinx.po:403: incompatible format for placeholder 1: 'r' and 's' are not compatible
compiling catalog sphinx/locale/zh_CN/LC_MESSAGES/sphinx.po to sphinx/locale/zh_CN/LC_MESSAGES/sphinx.mo
...
Compiling failed.

Apart from the ％ problem at sphinx/locale/ja/LC_MESSAGES/sphinx.po:1280 (there were others earlier so I think transifex has been updated recently) the problem is with strings such as

#: sphinx/ext/coverage.py:46
#, python-format
msgid "invalid regex %r in %s"
msgstr "%s 内に無効な正規表現 %r があります"

where translation permutes order. For Chinese:

#: sphinx/registry.py:464
#, python-format
msgid ""
"the extension %r was already merged with Sphinx since version %s; this "
"extension is ignored."
msgstr "自版本 %s 开始，扩展 %r 已合并至 Sphinx；该扩展被忽略。"

When more translation work will be done at transifex more and more such occurrences will arise for languages where order is permuted with respect to English.

It seems usage of .fmt should solve this.

edit: I of course meant "usage of .format() would solve this"

[tk0miya]

I fixed Japanese translations in #6823. But error in Chinese translations still remains. So I keep this opened.