Allocated memory bloat on project build attempt (yarn build) about fluent-ui-react

[kuzhelov]

Key takeaways

• major impact is provided by enabled strictNullCheck TS compiler flag
  • skipLibCheck, skipDefaultLibCheck, noStrictGenericChecks
• while yes, we can fix types for this PR and 'resolve' CI build issue for it, with that we will effectively agree that stability of our build infrastructure is dependent on the code we are providing in sources (?!)
• introduce larger allocation size limits helps, but only for the case where 'strictNullCheck' is disabled

Proposed solutions/mitigation strategies

• disable strictNullCheck flag as a mitigation step (#157)
• • increase memory limits
• • run build tasks (for sources and docs) sequentially

Details

Here are the results from the investigation process held by me and @miroslavstastny. Essentially, the following approaches were tries to solve the problem (results from all of them were subsequently monitored by running process with trace_gc flag):

• increase memory size available for heap allocation (max_old_space_size flag)
  • although memory size was increased, this move haven't resulted in problem being solved: all the available space was consumed by build tasks (docs + sources, simultaneously), and subsequent allocation requests fail. Worth to notice that gradient of allocation size growth is quite impressive - we do not even reaching plato at this point
• our next thought was about problems with build process pipeline. We've tried to limit amount of concurrently running tasks, the simplest move - to make sources and docs run sequentially. This hasn't solved the problem or made any effect on amount of memory consumed
• next thing that has been tried - remove strictNullCheck flag from TS compiler config. This has resulted in much moderate memory consumption by the compiler, with even default threshold being never exceeded (irregardless of whether sources were built in parallel with docs or not)

cc: @levithomason, @miroslavstastny

[kuzhelov]

as problem is reproing only for docs build, maybe it makes sense to apply disabled strictNullChecks flag only for the docs files? However, problem's scope should be strictly defined first..

[kuzhelov]

will be addressed and tracked by #184, closing