Installer package identifiers and the mystery of the missing Java 11 files

As part of developing new AutoPkg recipes to support SapMachine‘s new Long Term Support (LTS) distribution for Java 17, I ran into a curious problem when testing. When I ran the SapMachine Java 17 LTS installer that was being generated by AutoPkg, I was seeing the following behavior:

• SapMachine Java 17 LTS is installed by itself – no problem
• SapMachine Java 17 LTS installed, then SapMachine Java 11 LTS is installed – no problem
• SapMachine Java 11 LTS installed, then SapMachine Java 17 LTS is installed – SapMachine Java 11 LTS is removed, only SapMachine Java 17 LTS is installed now.

I double-checked the preinstall script for the SapMachine Java 17 LTS installer. It is supposed to remove an existing SapMachine Java 17 LTS installation with the same version info, but it should not have also been removing SapMachine Java 11 LTS. After a re-review of the script and additional testing, I was able to rule out the script as the problem. But what was causing this behavior? Also, why was it happening in this order?

• SapMachine Java 11 LTS installed, then SapMachine Java 17 LTS is installed

But not this order?

• SapMachine Java 17 LTS installed, then SapMachine Java 11 LTS is installed

The answer was in how the package’s package identifier was set up. For more details, please see below the jump.