[cpuguy83]

This is more stuff where we weren't accounting for concurrent access.

Seen this on latest buildx stable image:

fatal error: concurrent map writes

goroutine 23041 [running]:
internal/runtime/maps.fatal({0x2068176?, 0x1d660e0?})
	/usr/local/go/src/runtime/panic.go:1046 +0x18
github.com/moby/buildkit/sourcepolicy.(*wildcardCache).Match(0xc003813a30, {0xc001f020c0, 0x3e})
	/src/sourcepolicy/formatter.go:66 +0xbf
github.com/moby/buildkit/sourcepolicy.match(0xc0055ed320, {0xc001f020c0, 0x3e}, {0x0, 0x0, 0xc0027fa2a0?}, 0x0)
	/src/sourcepolicy/matcher.go:56 +0x48f
github.com/moby/buildkit/sourcepolicy.(*Engine).evaluatePolicy(0xc002ccb5c0, {0x23ad8b8, 0xc0026926c0}, 0xc001cdaaa0, 0xc00344cd40)
	/src/sourcepolicy/engine.go:133 +0x305
github.com/moby/buildkit/sourcepolicy.(*Engine).evaluatePolicies(0xc002ccb5c0, {0x23ad8b8, 0xc0026926c0}, 0xc00344cd40)
	/src/sourcepolicy/engine.go:101 +0x7a
github.com/moby/buildkit/sourcepolicy.(*Engine).Evaluate(0xc002ccb5c0, {0x23ad8f0, 0xc001cdaa50}, 0xc00344cd40)
	/src/sourcepolicy/engine.go:84 +0x312
github.com/moby/buildkit/solver/llbsolver.(*policyEvaluator).Evaluate(0xc002f8f950, {0x23ad8f0, 0xc001cdaa50}, 0xc003d10420)
	/src/solver/llbsolver/policy.go:27 +0x90
github.com/moby/buildkit/solver/llbsolver.loadLLB.func1()
	/src/solver/llbsolver/vertex.go:353 +0x6e
golang.org/x/sync/errgroup.(*Group).Go.func1()
	/src/vendor/golang.org/x/sync/errgroup/errgroup.go:93 +0x50
created by golang.org/x/sync/errgroup.(*Group).Go in goroutine 22895
	/src/vendor/golang.org/x/sync/errgroup/errgroup.go:78 +0x95

[tonistiigi]

would it make sense to use sync.OnceValue for re/w in here instead?

[cpuguy83]

Updated, I think this is what you meant?

[cpuguy83]

Fixed a stray newline causing lint failure.