Comment 0 for bug 1797557

As I reported in comments on the end of Bug #1769657 "update toolchain packages for bionic" the updates have broken the ability upgrade the package(s). Specifically, the 'dpkg --unpack' stage breaks because, from what I can tell, some of the .dpkg-new files are being deleted before they are due to be renamed:

$ sudo dpkg --unpack /var/cache/apt/archives/libc6-armhf-cross_2.27-3ubuntu1cross1.1_all.deb |& tee /tmp/dpkg-unpack.log
(Reading database ... 406492 files and directories currently installed.)
Preparing to unpack .../libc6-armhf-cross_2.27-3ubuntu1cross1.1_all.deb ...
Unpacking libc6-armhf-cross (2.27-3ubuntu1cross1.1) over (2.27-3ubuntu1cross1) ...
dpkg: error processing archive /var/cache/apt/archives/libc6-armhf-cross_2.27-3ubuntu1cross1.1_all.deb (--unpack):
 unable to open '/usr/arm-linux-gnueabihf/lib/ld-2.27.so.dpkg-new': No such file or directory
Errors were encountered while processing:
 /var/cache/apt/archives/libc6-armhf-cross_2.27-3ubuntu1cross1.1_all.deb

$ sudo dpkg --unpack /var/cache/apt/archives/libc6-dev-armhf-cross_2.27-3ubuntu1cross1.1_all.deb |& tee /tmp/dpkg-unpack.log
(Reading database ... 406492 files and directories currently installed.)
Preparing to unpack .../libc6-dev-armhf-cross_2.27-3ubuntu1cross1.1_all.deb ...
Unpacking libc6-dev-armhf-cross (2.27-3ubuntu1cross1.1) over (2.27-3ubuntu1cross1) ...
dpkg: error processing archive /var/cache/apt/archives/libc6-dev-armhf-cross_2.27-3ubuntu1cross1.1_all.deb (--unpack):
 unable to open '/usr/arm-linux-gnueabihf/lib/Mcrt1.o.dpkg-new': No such file or directory
Errors were encountered while processing:
 /var/cache/apt/archives/libc6-dev-armhf-cross_2.27-3ubuntu1cross1.1_all.deb

$ apt-cache policy libc6-armhf-cross
libc6-armhf-cross:
  Installed: 2.27-3ubuntu1cross1
  Candidate: 2.27-3ubuntu1cross1.1
  Version table:
     2.27-3ubuntu1cross1.1 500
        500 http://gb.archive.ubuntu.com/ubuntu bionic-updates/main amd64 Packages
        500 http://gb.archive.ubuntu.com/ubuntu bionic-updates/main i386 Packages
 *** 2.27-3ubuntu1cross1 500
        500 http://gb.archive.ubuntu.com/ubuntu bionic/main amd64 Packages
        500 http://gb.archive.ubuntu.com/ubuntu bionic/main i386 Packages
        100 /var/lib/dpkg/status

I've analysed both failures using a combination of 'dpkg --debug 77777', strace, and inotifywait, but I've not familiar enough with the dpkg logic to determine what is going wrong.

I'm attaching debug, strace and inotifywait logs for 'libc6-armhf-cross' where 'ld-2.27.so.dpkg-new' appears to be the problem.