`apk update/upgrade --no-cache` exits with exitstatus 0, where it uses 2 without `--no-cache`
apk update exits with status 2 if it fails to download files, but when using --no-cache it does not.
This might be ok given that the cache is not updated, but also affects apk upgrade, where it certainly should be a failure from what I can see.
% docker run -it --rm alpine
/ # apk update; echo $?
fetch http://dl-cdn.alpinelinux.org/alpine/v3.12/main/x86_64/APKINDEX.tar.gz
ERROR: http://dl-cdn.alpinelinux.org/alpine/v3.12/main: temporary error (try again later)
WARNING: Ignoring APKINDEX.2c4ac24e.tar.gz: No such file or directory
fetch http://dl-cdn.alpinelinux.org/alpine/v3.12/community/x86_64/APKINDEX.tar.gz
ERROR: http://dl-cdn.alpinelinux.org/alpine/v3.12/community: temporary error (try again later)
WARNING: Ignoring APKINDEX.40a3604f.tar.gz: No such file or directory
2 errors; 14 distinct packages available
2
/ # apk update --no-cache; echo $?
fetch http://dl-cdn.alpinelinux.org/alpine/v3.12/main/x86_64/APKINDEX.tar.gz
WARNING: Ignoring http://dl-cdn.alpinelinux.org/alpine/v3.12/main/x86_64/APKINDEX.tar.gz: temporary error (try again later)
fetch http://dl-cdn.alpinelinux.org/alpine/v3.12/community/x86_64/APKINDEX.tar.gz
WARNING: Ignoring http://dl-cdn.alpinelinux.org/alpine/v3.12/community/x86_64/APKINDEX.tar.gz: temporary error (try again later)
OK: 14 distinct packages available
0
/ # apk --version
apk-tools 2.10.5, compiled for x86_64.
/ # cat /etc/os-release
NAME="Alpine Linux"
ID=alpine
VERSION_ID=3.12.1
PRETTY_NAME="Alpine Linux v3.12"
HOME_URL="https://alpinelinux.org/"
BUG_REPORT_URL="https://bugs.alpinelinux.org/"Using alpine:latest Docker image (d6e46aa2470d).