Definition of @heading for LaTeX messes with vertical spacing

[Gavin Smith]

I found bad vertical spacing with the @heading-like commands in the
LaTeX output.  It can be seen in the Tips appendix in texinfo.texi, or
here is a minimal example:

\input texinfo

@chapter One 
 
@noindent test test  test  test  test 
@example
a
 b
c
@end example


@heading Heading

@noindent test test  test  test  test 
@example
a
 b
c
@end example

@bye

Note in the image that there is no space before the second @example.

I found that it was due to the group used in the output of @heading:

\newcommand{\GNUTexinfonopagebreakheading}[2]{{\let\clearpage\relax 
\let\cleardoublepage\relax \let\thispagestyle\GNUTexinfoplaceholder #1{#2}}}
% ...
\GNUTexinfonopagebreakheading{\section*}{{Heading}}

If I replace the \GNUTexinfonopagebreakheading line with simply

{\section*{Heading}}

the output is the same.  However, if it is simply

\section*{Heading}

the vertical spacing is good.  I suspect that some redefinition of vertical
spacing is happening inside \section* and the group characters are stopping
this.

Evidently the attempt here to hook into LaTeX internals isn't reliable.
I don't have a fix for this.

I'm going to remove the \GNUTexinfonopagebreakheading uses for
@heading and below (keeping it for \chapheading and \majorheading), as
\section* doesn't cause a page break.

heading-spacing.png
Description: PNG image