[tex-live] Bug in TexLive 2005 and 2007? Non-writable aux-file

Heiko Oberdiek oberdiek at uni-freiburg.de
Wed Mar 7 00:38:10 CET 2007

On Tue, Mar 06, 2007 at 04:43:43PM -0600, Karl Berry wrote:

>     If the user does not provide a
>     file name, then he is probably unable/unwilling to provide
>     the correct error recovery.
> I see a difference between typing CTRL-C or CTRL-D to "give me an input
> file", and just pressing RET.  Handling of CTRL-C and CTRL-D has always
> been problematic; I've seen lots of different behavior over the years.
> I have no qualms about simply aborting given CTRL-C or CTRL-D.  That
> seems eminently desirable to me.
> However, in the case of just pressing RET, I see no harm in asking again

This thread with its seemingly non-trivial analysis shows, that
even the experts have difficulties to know, which exact file name
TeX uses, if he just presses RET.
  Therefore pressing RET cannot mean the user wants the file
name that the TeX port guesses. In most or even all cases
just pressing RET means, the user doesn't have a file name to try.
Thus the question for error recovery is: does it make sense
to continue without a file name?
* File output could be redirected to the terminal.
* An empty input file could be simulated.
* Eventually a scratch file similar to "texput.tex" could
  be used for DVI/PDF output if possible.
But all this doesn't solve the original problem and is difficult
to implement. And one of the main questions remains unanswered.
How can the file name prompt be aborted without specifying a valid file.
There can even be circumstances (wrong TEXINPUTS, ...) where no valid
file exists or can be found.
  For example, LaTeX's workaround for input files `x.tex' requires
that x.tex can be found and it hopes hopes that the current catcodes
are appropriate.

> (not trying to open *any* files in the meantime).  As a TeX user, I
> would be rather surprised if the job aborted from simply pressing RET.
> TeX has never behaved that way in the past.

The unbreakable file prompt loop is one of TeX's most annoying parts.
I clearly remember my despair as beginner when I was not be able
to finish the TeX job in such as situation. Clearly TeX forces its
users to become masochists. But is this the purpose of the program?

> Using a previous filename when RET is pressed, as is apparently
> happening now, seems worst of all.
> For me, the ideal would be a specific error message, like:
> ! You didn't type a filename, please do so.
> <*>
> Please type another input file name: 
> (Or maybe it'd be possible to get thrown into the regular error
> routines, so a help string could be provided?)

But this action does not provide more information than
the user had the first time. The help string could already
be provided the first time. A useful help string could be:
"An empty file name aborts the job" :-)

> Wdyt?

I think endless loops are evil. And this kind of loops should
be also avoided in the interactive prompt loop for the file name.

Yours sincerely
  Heiko <oberdiek at uni-freiburg.de>

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