@AlanMunn Do you know if titlesec or titletoc do anything funky with things like \mainmatter? There's a question about a document using the inevitable 'template', but this one doesn't just load a bunch of packages in the wrong order, it uses \if@mainmatter even though the base class is report. Assuming it doesn't just give an error for every \chapter, I'm wondering where it gets the conditional from.

It really does. Dammit. I hate titlesec.

@egreg Hurry, you got yourself a new one (but not from the same guy)

@DavidCarlisle I was looking if one can merge xr and xr-hyper and saw that they handle file names with spaces differently: xr-hyper don't like them at all, and xr ignores a space at the end ;-(

\begin{filecontents}{endspace .aux}
\newlabel{test1}{{space}{1}{}{}{}}
\end{filecontents}

\begin{filecontents}{middle space.aux}
\newlabel{test2}{{space}{1}{}{}{}}
\end{filecontents}

\documentclass{article}
%\usepackage{xr-hyper} %errors
\usepackage{xr}        %doesn't find "endspace .aux" looks for endspace.aux
\externaldocument{endspace }
\externaldocument{middle space}
\begin{document}
\ref{test1}, \ref{test2}
\end{document}

This looks like an expansion problem, but I don't think it's solvable. Certainly none of the usual TikZ expansion tricks seem to work. tex.stackexchange.com/q/703009/2693

@AlanMunn no tikz wants to put every char in a \hbox and that doesn't work with \enquote. You need simple text.

@UlrikeFischer Ok that makes sense given what it has to do with the text.

@UlrikeFischer that was the plan, just stalled as hyperref changed \label :-)

@UlrikeFischer I suppose "serves you right" isn't the correct response to %doesn't find "endspace .aux" ?

@DavidCarlisle well nobody complained about it, so I wouldn't mind if it doesn't, but one can't replace xr by xr-hyper as the testsuite errors (there was github issue 223 ...).

@UlrikeFischer we should merge though even if some edge cases break, having two makes no sense once all the label internals have been rationalised

@DavidCarlisle yes I quite agree. But I think the new version should properly support files with spaces, so both above should work.

@DavidCarlisle but beside this the testsuite seems to pass if one exchange xr by the xr-hyper code.

@UlrikeFischer yes agreed