ARB placeholder types not compatible with Flutter localizations

[msonntag13]

As per a commit in the Flutter localizations tool from November 2024, it is now preferred (effectively enforced) to match ARB placeholder types between all languages. Means if there's a template ARB file with defines a placeholder, all other ARB files must include and match that placeholder.

However, using the Localizely CLI, a pull command would automatically populate the placeholders in all files, but not their types. E.g.:

template_arb_file

  "someTranslation": "With some {placeHolder}",
  "@someTranslation": {
    "placeholders": {
      "placeHolder": {
         "type": "String"
      }
    }
  }

Would become this in any other languages ARB file:

  "someTranslation": "Another language {placeHolder}",
  "@someTranslation": {
    "placeholders": {
      "placeHolder": {}
    }
  }

Which leads to the following error when flutter gen-l10n is executed:

The placeholder, type, has its "type" resource attribute set to the "null" type in locale "<OTHER_LANGUAGE>", 
but it is "String" in the template placeholder. For compatibility with template placeholder, 
change the "type" attribute to "String".

This also happens if no specific type is defined in the template ARB file, in this case complaining about null (in other language) not matching Object from template ARB.

Is there any way around this?

[lzoran]

Hi @msonntag13,

Thank you for reporting this!

The easiest way to fix this issue is by updating the 'Custom attributes' of the localization messages that lack type information on Localizely. Here's how to do it:

• Navigate to the Translations page and open the dialog for editing the string key. You can do this by either clicking on a message identifier or the "Settings" button next to it.
• In the "Edit string key" dialog, switch to the "Custom" tab.
• Add the missing types for any placeholders present in the message.
• Save the changes within the dialog.

After you've updated the missing types on the Localizely platform for all your localization messages, simply pull the arb files using the localizely-cli (localizely-cli pull) and run the gen-l10n generation (flutter gen-l10n) again to verify if the issue has been resolved.

I hope this solution works out for you.

[msonntag13]

Hi @lzoran,
thank you for the hint, I'll try this out! Is there any way this is can done automatically through the CLI once I push the template ARB file? Or should this already set this property if it's defined there?

[lzoran]

For now, there are certain constraints regarding the overwriting of resource attributes from ARB files during subsequent uploads to Localizely, so those need to be done manually in web console. I know that there are plans to address and improve this issue.