Section translation is in an early stage and we plan to enable the tool in one wiki (Bengali Wikipedia, T271397) to learn from its use with real content.
Since the tool was designed to select any target language, users may be able to select a different language to publish their translation on. This may lead to errors and confusion.
This ticket proposes to (a) investigate the current status (what happens is someone selects a different language to publish) and (b) avoid problematic situations.
One approach to avoid problems, would be to limit the language selection for the target language to those languages where the tool is enabled. For the cases where there is only one option, the target language element can be an non-interactive label (using Base20/#54595d for color and no drop-down icon) as illustrated below:
Since we plan to enable in one wiki and learn about its use for a while, it is ok to consider a temporary fix that we can generalize later once the tool is available to more wikis.
We may also need to define how to prevent the selection of the language pair "Bengali-> Bengali". The standard behaviour would be to swap the other language, but with only one target language we don't have such option. So excluding it from source selection may be a temporary fix.