Bug#251690: Possibly discover problem?
I just finished debugging a very similar issue to bug 251690, where the
preinst of xserver-xfree86 failed with exit code 127. As in the
submitter's case, there was no useful debugging output, even with variables
DEBUG_XFREE86_PACKAGE=true and DEBIAN_FRONTEND=readline
exported as you requested. The problem turned out to be that discover
crashed silently in the xserver-xfree86 config script.
In my case, this was due to libcurl2 abruptly changing soname (I've just
filed a grave bug against libcurl2, #252348), but since the broken libcurl2
package only entered unstable today, the submitter likely has a different
problem. Still, I suggest investigating discover as a first possible
culprit. Maybe in the X inst/config/rm scripts, you could output debugging
messages before and after calls to discover when DEBUG_XFREE86_PACKAGE is
set, to aid in catching these problems?
Kevin B. McCarty <email@example.com> Physics Department
WWW: http://www.princeton.edu/~kmccarty/ Princeton University
GPG: public key ID 4F83C751 Princeton, NJ 08544