Function TestUninitializedVarAccess

state_test.go:554–583

This test exposed a panic caused by accessing an unassigned var in the lua registry. The panic was caused by initCallFrame. It was calling resize() on the registry after it had written some values directly to the reg's array, but crucially, before it had updated "top". This meant when the resize occ

(t *testing.T)

// directly to the reg's array, but crucially, before it had updated "top". This meant when the resize occurred, the
// values beyond top where not copied, and were lost, leading to a later uninitialised value being found in the registry.
func TestUninitializedVarAccess(t *testing.T) {
	L := NewState(Options{
		RegistrySize:    128,
		RegistryMaxSize: 256,
	})
	defer L.Close()
	// This test needs to trigger a resize when the local vars are allocated, so we need it to
	// be 128 for the padding amount in the test function to work. If it's larger, we will need
	// more padding to force the error.
	errorIfNotEqual(t, cap(L.reg.array), 128)
	ctx, cancel := context.WithCancel(context.Background())
	L.SetContext(ctx)
	defer cancel()
	errorIfScriptFail(t, L, `
		local function test(arg1, arg2, arg3)
			-- padding to cause a registry resize when the local vars for this func are reserved
			local a0,b0,c0,d0,e0,f0,g0,h0,i0,j0,k0,l0,m0,n0,o0,p0,q0,r0,s0,t0,u0,v0,w0,x0,y0,z0
			local a1,b1,c1,d1,e1,f1,g1,h1,i1,j1,k1,l1,m1,n1,o1,p1,q1,r1,s1,t1,u1,v1,w1,x1,y1,z1
			local a2,b2,c2,d2,e2,f2,g2,h2,i2,j2,k2,l2,m2,n2,o2,p2,q2,r2,s2,t2,u2,v2,w2,x2,y2,z2
			local a3,b3,c3,d3,e3,f3,g3,h3,i3,j3,k3,l3,m3,n3,o3,p3,q3,r3,s3,t3,u3,v3,w3,x3,y3,z3
			local a4,b4,c4,d4,e4,f4,g4,h4,i4,j4,k4,l4,m4,n4,o4,p4,q4,r4,s4,t4,u4,v4,w4,x4,y4,z4
			if arg3 == nil then
				return 1
			end
			return 0
		end

		test(1,2)
	`)
}

func BenchmarkCallFrameStackPushPopAutoGrow(t *testing.B) {
	stack := newAutoGrowingCallFrameStack(256)