“Watch Document”: Display BibTeX Errors in Notification Window

[sanssecours]

Currently “Watch Document” only displays an unspecific message in the notification window if a .bib file included via biblatex contains an error. The command should show a more helpful error message.

Steps to Reproduce

1. Create a new file References.bib with the following content

   @article{citekey,
     title={Title},
     author={Author},
     year={1970},
     publisher={ACM}error
   }

2. Create a new file Test.tex with the following content

   \documentclass{article}
   
   \usepackage{cite}
   
   \begin{document}
   Citation~\cite{citekey}
   
   \bibliographystyle{plain}
   \bibliography{References}{}
   \end{document}

3. Invoke “Watch Document”

Current Result

The notification window displays the following error message:

Could not find any messages containing line information.
Please take a look at the log file Test.latexmk.log to find the source of the problem.

Expected Result

The notification window should show something like this:

ERROR References.bib:5 — I was expecting a `,' or a `}'