Bug#994152: ca-certificates fails foreign installation: doesn't know about openjdk-18

[Helmut Grohne]

Package: ca-certificates-java
Version: 20190909
Severity: important
User: debian-cross at lists.debian.org
Usertags: ftcbfs
Control: affects -1 + src:astyle

ca-certificates-java.postinst currently fails when installing
default-jdk for a foreign architecture. The situation picks different
openjdk versions for native and foreign. In particular, the native one
tends to be openjdk-18, which is missing in
ca-certificates-java.postinst. Example failure:

| Setting up ca-certificates-java (20190909) ...
| head: cannot open '/etc/ssl/certs/java/cacerts' for reading: No such file or directory
| /usr/bin/which: this version of `which' is deprecated; use `command -v' in scripts instead.
| /var/lib/dpkg/info/ca-certificates-java.postinst: line 101: java: command not found
| dpkg: error processing package ca-certificates-java (--configure):
|  installed ca-certificates-java package post-installation script subprocess returned error exit status 127

I guess that adding openjdk-18 support to the postinst fixes this, but I
haven't verified.

The failure can be reproduced as follows:

mmdebstrap --variant=apt --architectures=amd64,ppc64el --include=default-jdk:ppc64el sid /dev/null

Helmut