[pdftex] pdftex core dump when including certain pdf files

[Werner LEMBERG]

>> It's not only file size!  Accessing the disc for writing
>> unnecessarily large files is also time consuming.
> 
> How often does this need to be done?  If only once to produce the
> final PDF, what is the problem?

The intermediate files become much larger if they contain fonts that
are not subsetted.  A lilypond developer has disabled subsetting for
testing purposes; doing so increases the necessary disk space by a
factor of around three, IIRC, which means that you then need more than
7 GByte for building the whole documentation, which is excessively
huge.

> If only intermediate, why do they need to be valid PDFs?

Well, all PDF snippets created by lilypond (and gs) are read by pdftex
(or xetex) to create the final texinfo file, so you need valid PDFs, I
guess.

>>> it's certainly worthwhile to investigate what ghostscript can do
>>> for you.
> 
> Ghostscript can read individual files that add to the construction
> of a PostScript or PDF file.  Those files do not need to be complete
> documents.  They just need to contain streams of graphic commands or
> other valid PostScript source, which add to what you want to show on
> a page.

OK, but I don't see how you want me to do that.

> Postscript is an incredibly powerful programming language, [...]

Indeed, but the standard is no longer evolving, and support for
current font formats (OTF, OTC) is missing.

>> Note that ghostscript is *not* capable to merge various subsetted
>> fonts back to a single one: too much information is already lost
>> during the subsetting process.
> 
> Do you believe this is a deliberate choice, or just accidental?

It's not a mistake, as far as I know, but indeed not possible.

>>> This program is amazing.  But whom do I tell it?
>
> Well, actually it is a very good implementation of an extremely good
> programming language.

I think you refer to guile, which lilypond uses as a programmable
interface for almost everything.  While the programming language might
be `extremely good', the support isn't.  Since a few years we can't
upgrade to the latest guile 2.x series because essential features have
changed in an incompatible way, and the new `replacements' don't work
as expected and/or as needed.  This really threatens lilypond, because
virtually no application is still using guile 1.8, and GNU/Linux
distributions are going to throw out lilypond for this reason.


    Werner