"Extra \fi" error when defining mutually exclusive package options with conditionals

Question

I have been trying to create a package, which loads the babel package and sets the language with an option. I've been getting strange errors when trying to define mutually exclusive package options, so as to prevent babel options conflict. I've put together a MWE. Here is the failedpackage.sty file :

\NeedsTeXFormat{LaTeX2e}
\ProvidesPackage{failedpackage}

\newif\ifbabel@french
\newif\ifbabel@english
\newif\ifbabel@german

%% Option zone
\DeclareOption{french}{\babel@frenchtrue\babel@englishfalse\babel@germanfalse}
\DeclareOption{english}{\babel@frenchfalse\babel@englishtrue\babel@germanfalse}
\DeclareOption{german}{\babel@frenchfalse\babel@englishfalse\babel@germantrue}

\ExecuteOptions{french}

\ProcessOptions
%% end of Option zone


\ifbabel@frenchtrue
    \RequirePackage[french]{babel}
\fi
\ifbabel@englishtrue
    \RequirePackage[english]{babel}
\fi
\ifbabel@germantrue
    \RequirePackage[german]{babel}
\fi


\endinput

Here is the .tex file to compile :

\documentclass[report]

\usepackage[T1]{fontenc}
\usepackage[UTF8]{inputenc}

\usepackage{failedpackage}

\begin{document}

    Bonjour TeX.StackExchange !

\end{document}

And here is the .log document : http://paf.im/8a8tc

Well I guess the problem is caused by the fact that the compiler treats the conditional statements (e.g. \ifbabel@englishtrue) as undefined, but they have been defined right at the beginning of the .sty!

I don't understand.

Thanks in advance for your help.

Answer 1

1. Remove the suffix true from the \ifbabel@.... queries! You must use \ifbabel@french etc for the query, but \babel@frenchtrue or \babel@frenchfalse to set the state of the 'variable'.

2. Change \documentclass[report] to \documentclass{report}

---

\NeedsTeXFormat{LaTeX2e}
\ProvidesPackage{failedpackage}

\newif\ifbabel@french
\newif\ifbabel@english
\newif\ifbabel@german

%% Option zone
\DeclareOption{french}{\babel@frenchtrue\babel@englishfalse\babel@germanfalse}
\DeclareOption{english}{\babel@frenchfalse\babel@englishtrue\babel@germanfalse}
\DeclareOption{german}{\babel@frenchfalse\babel@englishfalse\babel@germantrue}

\ExecuteOptions{french}

\ProcessOptions
%% end of Option zone


\ifbabel@french
\RequirePackage[french]{babel}
\fi

\ifbabel@english
\RequirePackage[english]{babel}
\fi
\ifbabel@german
\RequirePackage[german]{babel}
\fi


\endinput

Main.tex

\documentclass{report}

\usepackage[T1]{fontenc}
\usepackage[utf8]{inputenc}     %

\usepackage{failedpackage}

\begin{document}

Bonjour TeX.StackExchange !

\end{document}