KSP 1.9.21-1.0.15 leaking memory & causing OOMs for Buck

[jbarr21]

KSP 1.9.21-1.0.15 has started leaking memory and causing OOM issues & GC thrash when being used in a daemon environment. Our Buck builds use a long-lived buckd daemon process:

For subsequent commands, Buck checks for the running daemon process and if found, uses the daemon to execute the command. Using the Buck daemon can save significant time as it avoids the overhead of starting a Java virtual machine (JVM) and loading the Buck class files

I performed the same build of a smaller app (larger apps fail to compile after 2x their normal time due to OOM or stuck in GC thrash):

• 1.0.14: 1.5 GB used
• 1.0.16: 5 GB used

1.0.16 is on the left, 1.0.14 on the right. At the end of compilation, there were 116 mockproject instances in memory on the new version as opposed to 0 on the older version.

MockProject was identified as a potential leak by Memory Analyzer Tool & the path to GC roots looks like:

[jbarr21]

dupe since original issue was not fully resolved with the initial fix