capfirst filter breaks translation context in template

[Dylan Verheul]

Using the cap first filter breaks any context used in translation using the trans template tag.

{% trans "species" context "singular" %}
# works as expected, results in translation of 'species' with context 'singular'

{% trans "species"|capfirst %}
# works as expected, results in translation of 'species' without context, capfirst applied

{% trans "species"|capfirst context "singular" %}
# BROKEN, results in translation of 'species' without context, capfirst applied

[Aymeric Augustin]

I can't reproduce the issue on master.

With this template and the appropriate French translations:

{% trans "species" %}
# works as expected, results in translation of 'species'

{% trans "species" context "singular" %}
# works as expected, results in translation of 'species' with context 'singular'

{% trans "species"|capfirst %}
# works as expected, results in translation of 'species' without context, capfirst applied

{% trans "species"|capfirst context "singular" %}
# works as expected, results in translation of 'species' with context 'singular', capfirst applied

I get this output:

espèces # works as expected, results in translation of 'species'

espèce # works as expected, results in translation of 'species' with context 'singular'

Espèces # works as expected, results in translation of 'species' without context, capfirst applied

Espèce # works as expected, results in translation of 'species' with context 'singular', capfirst applied

[Dylan Verheul]

Will test again to see if it is fixed.

[Dylan Verheul]

Confirmed, it works

[None]

The problem is actual again :(

[Tomáš Ehrlich]

Hi,
I tried to reproduce this problem, but it works for me:

# django.po
#: templates/test.html:3 templates/test.html.py:5 templates/test.html.py:6
msgid "species"
msgstr "espèces"

#: templates/test.html:4
msgctxt "singular"
msgid "species"
msgstr "espèce"

# test.html
{% load i18n %}

{% trans "species" %}
{% trans "species" context "singular" %}
{% trans "species"|capfirst %}
{% trans "species"|capfirst context "singular" %}

# tests.py
from django.template import Context
from django.template.loader import get_template

tmpl = get_template('test.html')
print(tmpl.render(Context({})))

# output
espèces
espèce
Espèces
Espèce

The message catalogue has wrong references for plural "species", but references are just informational. It doesn't affect the result.

If it still doesn't work for you (tested against 1.7.1 and master), could you please provide more info to reproduce this bug?

[Pascal Polleunus]

Same problem with Django 1.8.8.

[Aymeric Augustin]

Several people have tried and failed to reproduce the issue, as shown in the comments above. Can you provide reproduction instructions? Thanks.

[Przemysław Czumaj]

OK, I'll leave a reproduction example below if anyone will be interested, but after some more digging I found out what the issue was.

Within django/django/utils/translation/trans_real.py file there was an inline_re regex and this regex was badly constructed - up to Django 1.8.18. There was no "filters" block between translated string and a "context" keyword, so construction

{% trans 'string'|capfirst context 'context' %}

couldn't be recognised properly. This issue was fixed in Django 1.9.

So that's it. If you are still using Django 1.8 and need a fix for it use

{% filter capfirst %}{% trans 'string' context 'context' %}{% endfilter %}

construction instead or update your Django version.

---

I can provide additional information to this issue as I'm fighting with it right now.

Let's assume I have a template like this:

{% trans 'test_clean' %}
{% trans 'test_capfirst'|capfirst %}
{% trans 'test_context' context 'test_context' %}
{% trans 'test_context'|capfirst context 'test_context' %}
{% filter capfirst %}{% trans 'test_filter_context' context 'test_context' %}{% endfilter %}

Now let's run makemessages...

For:

{% trans 'test_clean' %}

I got:

msgid "test_clean"
msgstr ""

Result: OK!

For:

{% trans 'test_capfirst'|capfirst %}

I got:

msgid "test_capfirst"
msgstr ""

Result: OK!

For:

{% trans 'test_context' context 'test_context' %}

I got:

msgctxt "test_context"
msgid "test_context"
msgstr ""

Result: OK! Context is set as it should be.

For:

{% trans 'test_context'|capfirst context 'test_context' %}

I got:

msgid "test_context_capfirst"
msgstr ""

Comment: NOT OK! "msgctxt" key is missing, therefore Context is not set.

For:

{% filter capfirst %}{% trans 'test_filter_context' context 'test_context' %}{% endfilter %}

I got:

msgctxt "test_context"
msgid "test_filter_context"
msgstr ""

Comment: OK! Context is set as it should be.

[Dylan Verheul]

Thanks for the explanation, explains everything. Good to know it's fixed. I can confirm we haven't seen this bug since moving away from 1.8.