PO/POT now contains substitution names. Why?

[Matt Documatt]

Hi friends,
I've just updated from Sphinx 3.5.3 to 4.1.0. Now, "make gettext" extracts all substitution names. I can't find any details at https://www.sphinx-doc.org/en/master/changes.html.

For example, in RST:

.. |grid-manual-actions-action-trigger| image:: img/portlets/grid-manual-actions-action-trigger.nol10n.png

and in POT:

msgid "grid-manual-actions-action-trigger"
mststr ""

I'm sure that substitutions were not picked up MessageCatalogBuilder...

Is this behavior configurable and documented?

Thanks

Matt
https://techwriter.documatt.com

[Pieter Claeys]

Hi, I also recently encountered this problem, yesterday.
I think it's caused by this feature introduced in 4.0:

• #7784: i18n: The alt text for image is translated by default (without gettext_additional_targets setting)

I guess that an image without any 'alt text' uses the substitution reference. Which then ends up in the .po files

As a workaround, I have added an empty ':alt:'  option to each image directive in the rst file.  It's some work, but I found the strings are not longer present in the po/pot files.
Example

.. |grid-manual-actions-action-trigger| image:: some_image.png

   :alt:

One could debate if the current behavior is a defect  (from my point of view, I'd say that