lilypond-book: "Output would overwrite input file" error

[Jonathan Kulp]

Hi All,

I'm getting to know lilypond-book, both with html and LaTeX source 
files, running running Ubuntu 8.04 with 2.11.63.

As suggested in the manual, I've specifed an output directory (
--output=out).  So let's say my source file is
~/Book/filename.lytex

and my output directory is

~/Book/out/

I also have a couple of other \input{foobar.tex} files and am trying to 
include lily source files with \lilypondfile{foobar.ly}, stuff like that.

What I've found is that the first invocation of lilypond-book on the
source file works fine, but the next time I run it after making
changes to the sourcefile, it won't compile.  It took me a while to find 
the problem in the massive amounts of terminal output, but the culprit 
is apparently this one:

"lilypond-book: error: Output would overwrite input file; use --output."

What I've deduced from this is that lilypond-book must first make a copy
of my source file and put it in the output directory, then use that as
the input file.  Is this correct?  Because when I remove the .tex files
from the output directory and run lilypond-book on the original 
filename.lytex (in the main directory), it compiles correctly and 
creates the desired output.  My question is this: shouldn't the "input 
file" really be the one that's NOT in the output directory?  In other 
words, why doesn't lilypond-book take the command-line argument as the 
input file instead of the file that it has put in the output directory?
Is there a command-line option (such as the -e flag for convert-ly) that 
would allow overwriting the files?

I've made a workaround by adding cleanup lines to my lilybook
script to remove .tex files from the output directory, but it seems to 
me that the program should use the argument of the lilypond-book command 
as the input file and then overwrite the files inside the output 
directory instead of returning errors saying that output would overwrite 
the input file.

I don't remember this happening when using lilypond-book on the .itely 
files for the GDP.  Is it designed this way to avoid deleting files 
inadvertently?

Best,

Jon
--
Jonathan Kulp
http://www.jonathankulp.com