added documentation for #486 in ltnews33

base/doc/ltnews33.tex

@@ -78,6 +78,7 @@
 
 \let\cls\pkg
 \providecommand\env[1]{\texttt{#1}}
+\providecommand\acro[1]{\textsc{#1}}
 
 \vbadness=1400  % accept slightly empty columns
 
@@ -146,6 +147,38 @@ \subsection{Adjusting \env{itemize} labels with \cs{labelitemfont}}
 \githubissue{497}
 
 
+\subsection{A note on file names with spaces, dots or \acro{utf8} characters}
+
+In one of the the recent \LaTeX{} releases we improved the interface
+for specifying file names so that they can now safely contain spaces
+(as is common on Windows but also elsewhere), \acro{utf8} characters
+outside the \acro{ascii} range as well as names with several dots in
+it. In the past this was only possible by applying a special syntax
+(in cases of spaces), not at all for most \acro{utf8} characters and
+not in all circumstances for files with several dots.
+
+There is, however, one restriction to this: the syntax for
+\cs{include} and \cs{includeonly} expects not a file name but a file
+without its extension, which has to be \texttt{.tex}. That is, you are
+supposed to specify \verb=\include{mychap}= to include the file
+\file{mychap.tex} because \cs{include} internally also used its
+argument to write to \file{mychap.aux} and has to construct this name.
+However, because \TeX{} treats files in special manner when when they
+have the extension \texttt{.tex} it turned out one could add this
+extension in the argument to \cs{include} and the code would somehow
+loose it and still access the right \texttt{.aux} file.
+
+This is no longer the case and with the new implementation the
+official syntax is now enforced, i.e., the argument to \cs{include} is
+always interpreted as the file without its extension. Thus specifying
+\file{mychap.tex} now results in \LaTeX{} trying to include
+\file{mychap.tex.tex} and using \file{mychap.tex.aux}, because the
+argument is \emph{correctly} interpreted as the file name without its
+extension.
+%
+\githubissue{486}
+
+
 \subsection{\cs{end}\texttt{\textbraceleft document\textbraceright}
   should always start in v-mode}