# References not respecting margins with biblatex

I am using biblatex with the biber backend for my bibliography. The problem I encountered is that margins are not always respected. It seems to be a fairly common issue, cf. these possibly related questions (answers do not apply as far as I can tell):

## Repro code

I used the showframe package to help visualize the spilling.

\documentclass[12pt,draft]{report}
\usepackage{showframe}
\usepackage[backend=biber]{biblatex}

\begin{filecontents}{testbib.bib}
@article{cheng:ijrr:2004,
author = {Cheng, Peng and LaValle, Steven M.},
journal = {International Journal of Robotics Research},
pages = {1--37},
title = {{Resolution completeness for sampling-based motion planning with differential constraints}},
year = {2004}
}
\end{filecontents}
\bibliography{testbib.bib}

\begin{document}

\cite{cheng:ijrr:2004}

\printbibliography

\end{document}


So how can I solve this? Who's the culprit here? Is there workaround for this issue?

• add \usepackage{microtype} in your preamble. I might help. – pluton Jan 15 '16 at 9:13
• @pluton: it did not seem to have any effect. – BenC Jan 15 '16 at 9:19
• @Johannes_B thanks for the pointers, I added the hyphenation tag since that seems to be the source of the problem. – BenC Jan 15 '16 at 9:23
• Microtype has no effect with the draft option. – pluton Jan 15 '16 at 9:32

As @Johannes_B pointed out, the issue is with the hyphenation. Possible workarounds involve \raggedright (see No hyphens in biblatex) or \sloppy (see Hyphenation in bibliography with Biblatex).
With \appto{\bibsetup}{\raggedright}:
With \appto{\bibsetup}{\sloppy}: