Spacing before subequations

[Alexander Zeilmann]

Summary

There is a bug in the subequations environment that causes a too large spacing if the line before fills the entire paragraph.
This can be fixed by adding

\usepackage{etoolbox}
\preto\subequations{\ifhmode\unskip\fi}

to the preamble.

Maybe you want to add this to kaobook.

MWE

\documentclass{kaobook}

% \usepackage{etoolbox}
% \preto\subequations{\ifhmode\unskip\fi}

\begin{document}

A line that does not fill the paragraph has normal spacing
\begin{subequations}
	\begin{alignat}{1}
		a \\
		b
	\end{alignat}
\end{subequations}
A line that does fill the paragraph has too much spacing before the eq.
\begin{subequations}
	\begin{alignat}{1}
		a \\
		b
	\end{alignat}
\end{subequations}
A line after the equation.

\end{document}

[Federico Marotta]

Done, thanks!

[Meven Lennon-Bertrand]

@fmarotta I get an error on my end with your fix, it seems to be because you need to put the fix after importing amsmath rather than before. Can you confirm the issue comes from your side?
The CI after commit deaac8a and PR #221 all agree that there’s an issue with subequation introduced by that commit.

[Federico Marotta]

Sorry, my bad. I've merged #221, which should fix the problem.