Steps to reproduce;
1. Enable Content Translation module
2. Add 2 language
3. Make a new content type Test and Enable translation on it
4. Make a new image field and make it translatable (check "Users may translate this field"). Make sure File is set to not translatable, but the Alt and Title elements are translatable (default configurations)
5. Add a node with an image
6. Open translation form for the two other languages (so you edit them concurrently)
7. One the first translation form you upload a new image and save it
8. Then you save the second translation. Notice that there is no message like "The content has either been modified by another user, or you have already submitted modifications. As a result, your changes cannot be saved."
9. Go back to the first translation (in step 7). Notice that the uploaded image have been changed back to the original image because the unchanged image field in step 8 is saved over the new upladed image in step 7.
The same also goes for untranslatable fields. When someone edit concurrently different language versions of the node they will revert any changes made in untranslatable.
Problem
- It is not possible to update an untranslatable image file with translatable attributes as long as someone else edit translations concurrently
- It is not possible to update any untranslatable field as long as someone else edit translations concurrently, they will then revet any changes made (without knowing it themselves)
- For sites with many languages or where content is frequently updated this can be a significant drawback in the user experience
Proposed resolutions
- At least translatable image fields with untranslatable file should give a warning when it has been changed in a concurrent translation edit form: "The content has either been modified by another user, or you have already submitted modifications. As a result, your changes cannot be saved."
- Should maybe this warning come for any untranslatable field that is changed? Currently the same behavior is present for all untranslatable fields so it is impossible to updated them as long as someone edit a translations concurrently (as they will revert any changes made)
- Another solution could be to only save fields that have been changed in the form. In that way it would be possible to concurrently edit different language version of a node as long as the same field is not changed. However this doesn't seam feasable for translatable image fields with untranslatable files as these would need updated of alt and title attributes