buildah 1.39.0: When using BUILDAH_ISOLATION=chroot, symlinks are not followed correctly (?)

[mh21]

When using buildah on FC42/Rawhide, /etc/os-release seems to come from the host fs, not the container building environment.

Reproducer:

$ podman run  --rm  -it --pull=newer --privileged quay.io/fedora/fedora:42 sh -c "dnf install buildah -y; printf 'FROM quay.io/fedora/fedora:40\nRUN cat /etc/os-release\nRUN cat /usr/lib/os-release' > Dockerfile; buildah build .; BUILDAH_ISOLATION=chroot buildah build ."|grep PLATFORM_ID
PLATFORM_ID="platform:f40"
PLATFORM_ID="platform:f40"
PLATFORM_ID="platform:f42"
PLATFORM_ID="platform:f40"
$ podman run  --rm  -it --pull=newer --privileged quay.io/fedora/fedora:41 sh -c "dnf install buildah -y; printf 'FROM quay.io/fedora/fedora:40\nRUN cat /etc/os-release\nRUN cat /usr/lib/os-release' > Dockerfile; buildah build .; BUILDAH_ISOLATION=chroot buildah build ."|grep PLATFORM_ID
PLATFORM_ID="platform:f40"
PLATFORM_ID="platform:f40"
PLATFORM_ID="platform:f40"
PLATFORM_ID="platform:f40"

This runs a FC container via podman, installs buildah, and than outputs the contents of /etc/os-release and /usr/lib/os-release and greps for the version number, once without BUILDAH_ISOLATION and once with BUILDAH_ISOLATION=chroot.

On FC <= 41, this outputs PLATFORM_ID="platform:f40" four times. On FC >= 42, this outputs the PLATFORM_ID from the host fs once (for BUILDAH_ISOLATION=chroot and /etc/os-release).

Expected behavior: /etc/os-release comes from the container building environment.

Buildah version: buildah x86_64 2:1.39.0-1.fc42 fedora

[mh21]

This seems to work correctly on a FC42 container with buildah 1.38.1:

$ podman run  --rm  -it --pull=newer --privileged quay.io/fedora/fedora:42 sh -c "dnf install https://kojipkgs.fedoraproject.org//packages/buildah/1.38.1/1.fc42/x86_64/buildah-1.38.1-1.fc42.x86_64.rpm -y; printf 'FROM quay.io/fedora/fedora:40\nRUN cat /etc/os-release\nRUN cat /usr/lib/os-release' > Dockerfile; buildah build .; BUILDAH_ISOLATION=chroot buildah build ."|grep PLATFORM_ID
PLATFORM_ID="platform:f40"
PLATFORM_ID="platform:f40"
PLATFORM_ID="platform:f40"
PLATFORM_ID="platform:f40"