Re: roff.c question

[Ingo Schwarze <schwarze@usta.de>]

Hi Kristaps,

Kristaps Dzonsons wrote on Thu, Dec 02, 2010 at 02:29:41PM +0100:

> The groff_char.man page causes the blow-up (enclosed).

Typical GNU sabotage.  ;-(

Did you look at that code?
Take a seat first, lest you fall.

But seriously, how do you expect the following code to behave?

  .ds CH \\*[CH]
  \*(CH

Here is what groff does:

  EXAMPLES/loop.in:8: fatal error:
  input stack limit exceeded (probable infinite loop)

Apparently, the groff_char manual does not actually dereference this
self-referencing string, but the macro and if constructs are so
complicated that i guess i would need quite some time to disentangle
them and understand the reason.

In any case, this is all way above mandoc's head.
Young mandoc simply evaluates almost all conditions to false -
and runs straight into the trap.

I see two things this we can do here:

 1) roff_res() should not expand \\* or \\\\*,
    but it should expand \* and \\\*.

 2) We should implement some kind of stack limit
    and just bail out.

Planning to look into that tomorrow...

Yours,
  Ingo
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