chore(dot/state): replace sync.Map with map+mutex

[qdm12]

Changes

Tests

go test ./dot/state

Issues

• Remove all usage of sync.Map #2281

Primary Reviewer

[codecov]

Codecov Report

Merging #2286 (7136ee9) into development (a1d7269) will decrease coverage by 2.77%.
The diff coverage is 88.37%.

@@               Coverage Diff               @@
##           development    #2286      +/-   ##
===============================================
- Coverage        60.08%   57.30%   -2.78%     
===============================================
  Files              211      212       +1     
  Lines            27759    27768       +9     
===============================================
- Hits             16678    15912     -766     
- Misses            9357    10223     +866     
+ Partials          1724     1633      -91     

Flag	Coverage Δ
unit-tests	57.30% <88.37%> (-2.78%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
dot/state/offline_pruner.go	0.00% <0.00%> (ø)
dot/state/block_finalisation.go	44.64% <75.00%> (+0.66%)	⬆️
dot/state/block.go	42.45% <83.33%> (-2.48%)	⬇️
dot/state/hashtoblockmap.go	100.00% <100.00%> (ø)
dot/state/initialize.go	42.34% <100.00%> (+1.60%)	⬆️
dot/state/service.go	51.78% <100.00%> (-0.22%)	⬇️
dot/state/storage.go	49.72% <100.00%> (-2.35%)	⬇️
dot/state/tries.go	100.00% <100.00%> (ø)
dot/utils.go	0.00% <0.00%> (-80.65%)	⬇️
dot/build_spec.go	0.00% <0.00%> (-77.89%)	⬇️
... and 14 more

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[timwu20]

why do we need this context?

[qdm12]

To cancel all runInLoop goroutines all at once.

		for ctx.Err() == nil {
			f()
		}

and the cancel is called by the timer.

To be fair, all this feels like over-engineering but also like the right way to test for data races quickly, since it has to be 'tight' and as event-driven as possible. Probably a topic I should share in go-guild 😉

[timwu20]

I don't really see the need to use a context to handle cancellation. Could you not just close some channel to signify cancellation?

[qdm12]

Yes we can use a struct{} channel that gets closed, it's just that it then becomes:

stop := false
for {
	select {
	case <-stopGoroutines:
		stop = true
	default:
	}
	if stop {
		break
	}
	f()
}

Which is longer/more confusing I think. (and no I don't want to use goto 😄)