Bug#901717: debootstrap: Version 1.0.102 breaks use of file mirrors

[Christopher Obbard <obbardc@gmail.com>]

Package: debootstrap
Version: 1.0.102
Severity: important

This is a new bug introduced in 1.0.101

We use debootstrap with a custom file:// mirror to strap cross-arch
images for SBCs, with a second call to debootstrap --second-stage.

in this format:
debootstrap --foreign --arch="armhf" "buster" "test" "file://$PWD/repo"
cp /usr/bin/qemu-arm-static test/usr/bin/
chroot test/ /debootstrap/debootstrap --second-stage


Normally, debootstrap is used with http and https mirrors so this bug
will not be an issue for most users.

In git commit #48d77abf3a4209f7cff72aec20f618e086169aa7 the following
change breaks debootstrap for my use:
if there is no http or https mirror defined, revert MIRRORS back to
DEF_MIRROR. This is dangerous because now --second-stage will always
revert to DEF_MIRROR.
we should write the file mirror URI to sources.list

When trying to setup packages using setup_available, debootstrap exits
and the log complains it cannot find the cached Packages file from
DEF_MIRROR.

I think debootstrap in --second-stage mode should read the mirror URI
from sources.list or read the mirror URI from a new file called
/debootstrap/mirror.

What do you think?



Cheers!