Don't use one language's plural index formula with another language's string in the case of untranslated strings using format_plural().

If this is indeed a bug, a test might be needed in

core/modules/locale/lib/Drupal/locale/Tests/LocalePluralFormatTest.php

and the code can be changed in the formatPlural() function at

core/lib/Drupal/Core/StringTranslation/TranslationManager.php

Here is a patch of what I have in mind. Also, better title.

The patch causes a problem with the unit test and the mock translator. I modified the unit test slightly, mostly because I don't understand how expects() works: the return for the anonymous function can be anything and the unit test will still pass without the patch and fail with the patch.

Patch at #4 no longer applied, here is an updated patch.

The problem occurs also in D7. Here is a quick and dirty patch which fixes it. I have set it to not test because:

(a) we should fix it in D8 before thinking about D7
(b) there is no test in the D7 version
(c) the technique used will work except in cases where the string is translated in the target language but identical to the source language

I'm putting the patch here because I needed it for a project and figured it might be useful to others as well.

@sivaji@knackforge.com Thanks for this. You need to put the string "do-not-test" in the filename of the purposefully failing test to avoid the testbot setting the issue to "needs work".

[edit] this is actually still a problem, but format_plural() has been replaced with \Drupal::translation()->formatPlural(). Now you can reproduce this by installing the French language and running:

drush eval "print_r(\Drupal::translation()->formatPlural(0, '1 comment', '@count comments', array(), array('langcode' => 'fr')) . PHP_EOL);
print_r(\Drupal::translation()->formatPlural(0, '1 comment', '@count comments', array()) . PHP_EOL);
print_r(\Drupal::translation()->formatPlural(1, '1 comment', '@count comments', array(), array('langcode' => 'fr')) . PHP_EOL);
print_r(\Drupal::translation()->formatPlural(1, '1 comment', '@count comments', array()) . PHP_EOL);
print_r(\Drupal::translation()->formatPlural(2, '1 comment', '@count comments', array(), array('langcode' => 'fr')) . PHP_EOL);
print_r(\Drupal::translation()->formatPlural(2, '1 comment', '@count comments', array()) . PHP_EOL);
print_r(\Drupal::translation()->formatPlural(0, '1 whatever', '@count whatevers', array(), array('langcode' => 'fr')) . PHP_EOL);
print_r(\Drupal::translation()->formatPlural(0, '1 whatever', '@count whatevers', array()) . PHP_EOL);
print_r(\Drupal::translation()->formatPlural(1, '1 whatever', '@count whatevers', array(), array('langcode' => 'fr')) . PHP_EOL);
print_r(\Drupal::translation()->formatPlural(1, '1 whatever', '@count whatevers', array()) . PHP_EOL);
print_r(\Drupal::translation()->formatPlural(2, '1 whatever', '@count whatevers', array(), array('langcode' => 'fr')) . PHP_EOL);
print_r(\Drupal::translation()->formatPlural(2, '1 whatever', '@count whatevers', array()) . PHP_EOL);"

I think this might meet the requirements of a major bug, specifically:

• Interfere with normal site visitors' use of the site (for example, content in the wrong language, or validation errors for regular form submissions), even if there is a workaround.

• Cause a significant admin- or developer-facing bug with no workaround.

This bug will cause the number 1 to be displayed instead of the number 0 in an untranslated string, and it is reasonable to expect certain sites to not have 100% translation of all strings and still be used by visitors or developers in the target language (French, German...). Also, during active development of a site, stakeholders are aware that not all strings are translated but interact with the site nonetheless; they will expect some strings to show up in English, but they will not expect underlying data (numbers) to be wrong.

The following (hypothetical) examples might cause site visitors or admins to take action based on false information:

• If "You need one 1 badge to move to the next level; you currently have 1 badge" is displayed instead of "You need one 1 badge to move to the next level; you currently have 0 badges", users will react differently.
• If "You currently have 1 article to approve" is displayed instead of "You currently have 0 articles to approve", admins might assume there is an article to approve even when there is none.

Oops, I think this still should be 8.1.x.

I renamed @Sivaji's patches from #11. These are otherwise identical but I renamed one to use the "do-not-test" string, which should avoid a failure if the other one passes.

There seems to have been a lot of change in the class structure since the last patch, which is why it no longer applies. Here is a version which does apply, but I have not added a test yet:

The code is added to ./core/lib/Drupal/Core/StringTranslation/PluralTranslatableMarkup.php, and we probably need a unit test in ./core/tests/Drupal/Tests/Core/StringTranslation/PluralTranslatableMarkupTest.php

Setting to needs review to see if we do not break existing tests.

Here is the same patch as in #24, renamed; it should test with 8.5.x now.

See also the possibly related #2660338: [pp-3] locale_get_plural call in PluralTranslatableString is wrong

Here are two patches, one which only provides a failing test demonstrating the problem. The second is the same test along with a fix in code taken from previous patches.

This is still an issue on the Drupal 9.2.x branch in my tests.

The patch still applies; here is a new version (without the fuzziness) to trigger the testbot.

The test is failing because the following code gives "0 heure" without the patch (as it should) and "0 heures" (wrongly) with the patch. The patch needs to be updated so that the following code gives "0 heure".

use Drupal\Core\StringTranslation\PluralTranslatableMarkup;
use Drupal\Component\Gettext\PoItem;
$langcode= 'fr';
$count = 0;
$translated_string = \Drupal::translation()->translate('1 hour' . PoItem::DELIMITER . '@count hours', [], ['langcode' => $langcode]);
$plural = PluralTranslatableMarkup::createFromTranslatedString($count, $translated_string, [], ['langcode' => $langcode]);
$plural->render();