Longtable change breaks 'X' column specification

[svonohr]

Brief outline of the bug

The recent commit 6ec3409 breaks long tables with 'X' column specification. Building the example code below generates >100 errors and then terminates. I'm using the tabu package in my example to combine long tables and tabularx, so maybe this is also problem with tabu. Also, not including the color package makes the code work again.

Minimal example showing the bug

\RequirePackage{latexbug}       % <--should be always the first line (see CONTRIBUTING)!
\documentclass{article}

\usepackage{longtable}
\usepackage{tabu}
\usepackage{color}

\begin{document}

\begin{longtabu}{Xl}
1 & 2 \\
\end{longtabu}

\end{document}

Log file (required) and possibly PDF file

test.log

[davidcarlisle]

as should be indicated by the latexbug package this is an issue with tabu not with packages that we support directly. So we can not handle this here, sorry

See for example

https://tex.stackexchange.com/questions/469282/xcolor-breaking-and-align-environments-inside-tabu

https://tex.stackexchange.com/questions/468948/longtabu-and-color-compatibility/468958#468958

https://tex.stackexchange.com/questions/466147/tabu-very-recently-stopped-working-with-color-xcolor-or-with-fancyvrb/466261#466261

We are trying to reach the tabu author but he did post several years ago that the package was not maintained and currently he is not contactable by any email address that we know. Hopefully the patches discussed in those stackexchange answers will allow you to get your document working.

[FrankMittelbach]

The commit you mention doesn't break longtable's X specification. Instead it exhibits (one of several) issues with the tabu package that is not maintained by us. Note that latexbug clearly says

! Package latexbug Error: Third-party file(s)
(latexbug)                
(latexbug)                This test file uses third-party file(s)
(latexbug)                
(latexbug)                ==============
(latexbug)                tabu.sty
(latexbug)                ==============
(latexbug)                
(latexbug)                So you should contact the authors
(latexbug)                of these files, not the LaTeX Team!
(latexbug)                (Or remove the packages that load
(latexbug)                them, if they are not necessary to
(latexbug)                exhibit the problem).

and if you would remove tabu and use longtable there would be no such issue.

What happens inside tabu is that it does uses some internal implementation detail that is not part of a public interface and that detail has changed. We are aware if this fact and trying to contact the author of tabu to get the dependency on this no longer existing internal removed. Until that happened you may want to take a look at

https://tex.stackexchange.com/questions/466147/tabu-very-recently-stopped-working-with-color-xcolor-or-with-fancyvrb/466261#466261

If we don't get a reaction by the package owner it might be the case that the package evenually has to be forked as the correction in the kernel is necessary and the depdency in tabu should be there in the first place (or if then the package owner needs to be preparted to adjust).

[albert-github]

I think it is worth mentioning the new repository: https://github.com/tabu-fixed/tabu