Prevent biber from choking on "%" characters in abstract?

Question

This question is basically a duplicate of Error with percent sign in bib entry field when using biblatex/biber, however the accepted solution (biber configuration file set to skip the abstract field entirely) does not satisfy me and the question is a bit old so maybe something changed.

On the one hand, I would like to be able to use the abstract field if needed; on the other hand, export tools of some editors routinely include an unescaped "%" in abstracts. Is there a way around this that does not involve replacements in .bib files by hand or by an external software?

(BTW, I fail to see how biber can skip the abstract field even if it contains a "%", which proves that at some point it is not in LateX-mode of "ignore the comments", but cannot escape it reliably - that's purely for curiosity, but since I'm asking...)

MWE if needed: (the first pdflatex and biber compilations will work, for a successive pdflatex will fail with "Runaway argument?")

\documentclass{article}
\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}
\usepackage[english]{babel}
\usepackage{filecontents}

\begin{filecontents}{biblio.bib}
@article{key1,
    author="Ann Onymous",  
    journal="Some journal",  
    title="Title",  
    year="2017",  
    abstract={This abstract will fail because of an unescaped percent sign:
        10\% is fine, 10% is not.},  
    }
\end{filecontents}
\usepackage[backend=biber]{biblatex}
\addbibresource{biblio.bib}

\begin{document}
    Citation: \parencite{key1}.

    \printbibliography
\end{document}

Answer 1

biber is almost never in "LaTeX Mode". It is perl programm. It is easy for it to remove the complete entry. biber also doesn't choke on the %. But if it doesn't ignore it the whole entry ends up in a file processed by LaTeX. And then LaTeX chokes.

You can use a sourcemap to replace a % by \%. But imho it doesn't make much sense. If you want to use the abstract in LaTeX then you will have to go through the text anyway to check and correct the typesetting and change e.g. - to -- or a path like C:\documents.

\documentclass{article}
\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}
\usepackage[english]{babel}
\usepackage{filecontents}

\begin{filecontents}{biblio.bib}
@article{key1,
    author="Ann Onymous",
    journal="Some journal",
    title="Title",
    year="2017",
    abstract={This abstract will fail because of an unescaped percent sign:
        10\% is fine, 10% is not.},
    }
\end{filecontents}
\usepackage[backend=biber]{biblatex}
\addbibresource{biblio.bib}

\DeclareSourcemap{
  \maps[datatype = bibtex]{
    \map{
       \step[fieldsource = abstract,
          match = \regexp{([^\\])\%},
          replace = \regexp{$1\\\%}]
    }
  }
}


\begin{document}
    Citation: \parencite{key1}.

    \printbibliography
\end{document}