makeinfo --docbook vs @sp in @table

[Kevin Ryde]

In the debian i386 packaged makeinfo 4.6 (4.6-1), or my own build of
the latest cvs, the file foo.texi below processed with

    makeinfo --docbook foo.texi

gives an error

    foo.texi:12: @sp requires a positive numeric argument, not `<title>1'.


Other output formats seem ok (info, html, xml).

I wasn't actually wanting to use docbook, I was only running it on my
document to see that it passed.

Putting the @sp outside @title avoids the problem, but unless @sp in
this position is not allowed then it looks like a problem with docbook
output.

foo.texi
Description: TeXInfo document