It is not easy to produce a correct and helpful error message.

Indeed :/ I'm still trying to figure out the best way to show the messages. I'll make the PR a draft for now while I experiment with it

Ok so I think the main issue with the error messages is that it is not clear that pygettext is trying to match multiple specs and each of the error message relates to a different spec but for the same function call. I think we can make the message more structured in case there are multiple specs for the same function name. Something like this:

*** test.py:1: No keywords matched gettext call "_":        keyword="_": Expected a string constant for argument 1, got x        keyword="_:2": Expected a string constant for argument 2, got 42

The 'main' message makes it clear there are multiple specs and none of them matched. Then each sub-message is prefixed with a particular spec and shows the error for that spec. This is in my opinion clearer and makes it easier for the user to figure out where the problem is.

Whatxgettext does?

xgettext does not print anything when it can't extract a message, which is also an option I suppose, though pygettext has had these error messages since the beginning so I don't know if it's a good idea to get rid of them?

I implemented the example I showed above. It collects errors from all keyword specs for a given func name and then prints them all in a structured way that is hopefully both clear and helpful. I'd like to know what you think!

Alternatively, we could just get rid of the error messages which would simplify the code. Though as I wrote before, pygettext has always had these error messages and I think they are useful as they help you find i18n issues in your code.