Mfcttrf

I usually work with sesamanuel to produce texts for my math classes,
but in the new update of MacTeX, an error arises.

! Package ifluatex Error: Name clash, ifluatex is already defined.See the ifluatex package documentation for explanation.Type H for immediate help.... }

And I can not understand what is happening. Would someone know what to do in this case so he can use sesamanuel again? Thank you

It would be better if the class was fixed, but meanwhile you can do

RequirePackageifluatex
letifluatexrelax
documentclasssesamanuel

begindocument

enddocument

The documentation of the class states

On chargera le minimum d’extensions dans la classe afin de limiter les problèmes de compatibilités avec les différentes distributions TeX (distributions et versions de ces distributions). On aurait pu choisir de charger les extensions ifpdf, ifluatex et ifxetex pour tester le mode de compilation et agir en conséquence mais on n’a pas besoin de ce luxe : comme on est en tout début de classe, on peut utiliser des méthodes légèrement moins solides que celles fournies dans ces extensions mais très largement suffisantes ici.

We’ll load a bare minimum of packages in the class in order to limit problems of compatibility among different TeX distributions (distributions and versions thereof). We could have chosen to load the packages ifpdf, ifluatex and ifxetex in order to test the engine and act on consequence, but we don’t need such a luxury: as we’re at the very start of the class, we can employ methods slightly less robust than those provided by those packages, but largely sufficient here.

This statement is a bit weird:

• the package ifxetex has been unchanged since 2010




• the package ifluatex was modified in 2016 from its earlier version of 2011 but the change consisted in updating the version number (because it belongs to a larger bundle)




• the package ifpdf has a slightly different status and indeed it underwent some major changes between TeX Live 2015 and 2016, mainly to include better LuaTeX support, but has been basically stable since 2011 as well.

The class code contradicts the initial statement later on, when it loads etex, geometry, crop, ifmtarg, mathtools, amssymb, longtable, tabularx, multirow, xcolor (with table option), pst-all, pstricks-add, fancyhdr, fancyvrb, multicol, babel (with french option), numprint, besides some font packages. This doesn't qualify as “bare minimum” to my eyes.

The “culprit” is pst-all, that in turn loads pst-calculate and this one now loads siunitx, which requires ifluatex.

The final effect is that “limiting problems of compatibility” and to not load standard packages, basically unchanged for more than three years before the release of sesamanuel, actually creates them.

By the way, the 2015-01-01 release of LaTeX (which predates the release of sesamanuel) made etex no longer necessary.