django-makemessages-rs

A fast Rust alternative to Django's makemessages command. Produces byte-identical .po file output compared to django-extended-makemessages.

Tested against a ~2000 file Django project with ~3000 translatable strings across 5 locales:

Install

pip install django-makemessages-rs

Platform wheels are available for macOS (arm64, x86_64) and Linux (x86_64, aarch64).

Usage

django-makemessages-rs \
  -l en -l zh_Hant -l zh_Hans -l ko -l ja \
  --ignore .venv --ignore node_modules \
  --no-location --no-flags --sort-output \
  --no-fuzzy-matching --keep-header \
  --locale-dir locale

CI check mode

Use --check to verify translation files are in sync with source code. Exits with code 1 if any .po file would change:

django-makemessages-rs \
  -l en -l zh_Hant \
  --ignore .venv --ignore node_modules \
  --no-location --no-flags --sort-output \
  --no-fuzzy-matching --keep-header \
  --locale-dir locale \
  --check

Add --no-untranslated to also fail when a message has an empty msgstr, which catches strings that were extracted but never translated:

django-makemessages-rs -l en -l zh_Hant --locale-dir locale \
  --check --no-untranslated

--dry-run computes everything and reports, but never touches the tree.

Compiling to .mo

--compile runs msgfmt --check-format over each .po it wrote, the same way Django's compilemessages does, so a single invocation can refresh and compile the catalogs:

django-makemessages-rs -l en -l zh_Hant --locale-dir locale --compile

Options

-l, --locale <LOCALES>       Locales to generate (repeatable)
-x, --exclude <LOCALES>      Locales to exclude (repeatable)
-a, --all                    Update all existing locales
-s, --symlinks               Follow symlinks to directories when scanning
-i, --ignore <PATTERNS>      Patterns to ignore (directories/files)
    --no-default-ignore      Don't ignore CVS, .*, *~, *.pyc
-d, --domain <DOMAIN>        Domain name: django or djangojs [default: django]
-e, --extension <EXTS>       File extensions to examine [default: html txt py, or js for djangojs]
-k, --keyword <SPEC>         Extra xgettext keywordspec, e.g. -k t or -k t:1c,2
                             (repeatable; -k '' drops the defaults)
    --add-comments [TAG]     Emit preceding comments as #. lines
                             [default tag: Translators; bare = all comments]
    --detect-aliases         Treat `import gettext as x` aliases as keywords
    --root <PATH>            Root directory to scan [default: .]
    --locale-dir <PATH>      Locale directory [default: locale]
    --locale-path <PATH>     Extra locale directories, like LOCALE_PATHS (repeatable)
    --per-app-locale         Write into each app's own locale/ dir, like Django
    --no-location            Don't write #: filename:line lines (shorthand for --add-location never)
    --add-location <MODE>    Controls #: location comments: full (default), file, or never
    --no-flags               Don't write #, flags lines
    --sort-output            Generate sorted output
    --no-fuzzy-matching      Do not use fuzzy matching
    --keep-header            Keep the existing .po file header
    --no-obsolete            Remove obsolete message strings
    --no-wrap                Don't break long message lines
    --check                  Exit with error if .po files would change (dry-run)
    --dry-run                Compute everything but leave the tree untouched
    --no-untranslated        Exit with error if any message is untranslated
    --compile                Also compile .po to .mo afterwards (needs msgfmt)
    --width <WIDTH>          Wrap at this column instead of 80 (0 disables)
    --force-po               Write the .po even when it holds no messages
    --no-flag <FLAG>         Remove only this flag from '#,' lines (repeatable)
    --timing                 Show timing information

How it works

1. Walks the project tree using ignore (same engine as ripgrep)
2. Extracts translatable strings from .py and .html/.txt templates in parallel using rayon
3. Merges extracted strings with existing .po files, preserving translations
4. Writes updated .po files

The extractor handles:

• Python gettext(), ngettext(), pgettext(), npgettext() and the _() alias
• Django template tags: {% trans %}, {% translate %}, {% blocktrans %}, {% blocktranslate %}
• context "..." on both {% translate %} and {% blocktranslate %}, emitted as msgctxt
• {% blocktrans trimmed %} whitespace collapsing
• {% blocktrans %}...{% plural %}...{% endblocktrans %} plural forms
• _("...") constants in block tags, variable expressions and filter arguments ({{ foo|default:_("bar") }})
• Translators: comments, from # in Python and {# ... #} / {% comment %} in templates, written out as #. lines
• Python implicit string concatenation (_("foo" "bar")) and triple-quoted strings
• Template variable substitution, including filters and dotted lookups ({{ user.name|upper }} to %(user.name|upper)s)
• Literal % escaping to %%
• JavaScript sources under --domain djangojs
• custom translation functions via --keyword, using xgettext's keywordspec syntax (name, name:2, name:1c,2, name:1,2)

Only arguments that are entirely string literals are extracted, matching xgettext: _(getattr(obj, 'verbose_name', label)) yields nothing, while _("a" "b") yields ab.

Entries that disappear from the source are kept as #~ obsolete blocks so existing translations survive, matching gettext. Pass --no-obsolete to drop them instead.

New .po files get the correct Plural-Forms for their locale, taken from a table generated out of Django's own shipped catalogs (98 locales; ja, ko and zh_* are nplurals=1, Russian and Polish get their 4-form rules, and so on). Unknown locales fall back to the base language, then to nplurals=2; plural=(n != 1);.

Per-app locale directories

By default everything is written to a single --locale-dir. Pass --per-app-locale to follow Django's layout instead: any directory named locale/ is treated as a locale root for the app containing it, and each file's messages go to the nearest enclosing one.

appA/locale/en/LC_MESSAGES/django.po   <- strings from appA/
appB/locale/en/LC_MESSAGES/django.po   <- strings from appB/
locale/en/LC_MESSAGES/django.po        <- everything else

No Django settings or DJANGO_SETTINGS_MODULE required — runs as a standalone CLI.

Pre-commit / Git hooks integration

Add to your pyproject.toml dev dependencies:

"django-makemessages-rs"

Then in your pre-commit script:

uv run django-makemessages-rs \
  -l en -l zh_Hant \
  --ignore .venv --ignore node_modules \
  --no-location --no-flags --sort-output \
  --no-fuzzy-matching --keep-header \
  --locale-dir locale

Testing

cargo test --release

There is also a differential suite that runs the real Django makemessages over the same fixtures and compares the extracted messages, so behavioral drift from Django gets caught:

python3 -m venv tests/differential/.venv
tests/differential/.venv/bin/pip install django django-extended-makemessages
cargo build --release
./tests/differential/run.sh

It needs GNU gettext (xgettext, msgmerge, msguniq, msgattrib) on PATH, plus django-extended-makemessages for the fixtures covering --keyword, --add-comments and --detect-aliases. Headers and #: locations are excluded from the comparison; everything else (msgid, msgid_plural, msgctxt, #. comments, ordering) must match exactly.

License

MIT