1->0 set changes non longer should happen in Read

The new normalization should make preventing those changes unnecessary,
and will also prevent extra empty elements from being added when
resources are refreshed.

helper/plugin/grpc_provider.go

@@ -431,7 +431,7 @@ func (s *GRPCProviderServer) ReadResource(_ context.Context, req *proto.ReadReso
 		// here we use the prior state to check for unknown/zero containers values
 		// when normalizing the flatmap.
 		stateAttrs := hcl2shim.FlatmapValueFromHCL2(stateVal)
-		newInstanceState.Attributes = normalizeFlatmapContainers(stateAttrs, newInstanceState.Attributes, true)
+		newInstanceState.Attributes = normalizeFlatmapContainers(stateAttrs, newInstanceState.Attributes, false)
 	}
 
 	if newInstanceState == nil || newInstanceState.ID == "" {

helper/plugin/grpc_provider_test.go

@@ -709,6 +709,11 @@ func TestNormalizeFlatmapContainers(t *testing.T) {
 			attrs:  map[string]string{"map.%": "0", "list.#": "0", "id": "1"},
 			expect: map[string]string{"id": "1", "map.%": "0", "list.#": "0"},
 		},
+		{
+			prior:  map[string]string{"list.#": "1", "list.0": "old value"},
+			attrs:  map[string]string{"list.#": "0"},
+			expect: map[string]string{},
+		},
 	} {
 		t.Run(strconv.Itoa(i), func(t *testing.T) {
 			got := normalizeFlatmapContainers(tc.prior, tc.attrs, false)