plumb import changes to and from binary plan

internal/plans/planfile/tfplan.go

@@ -427,6 +427,13 @@ func changeFromTfplan(rawChange *planproto.Change) (*plans.ChangeSrc, error) {
 		}
 	}
 
+	if rawChange.Importing != nil {
+		ret.Importing = &plans.ImportingSrc{
+			ID: rawChange.Importing.Id,
+		}
+	}
+	ret.GeneratedConfig = rawChange.GeneratedConfig
+
 	sensitive := cty.NewValueMarks(marks.Sensitive)
 	beforeValMarks, err := pathValueMarksFromTfplan(rawChange.BeforeSensitivePaths, sensitive)
 	if err != nil {
@@ -759,6 +766,14 @@ func changeToTfplan(change *plans.ChangeSrc) (*planproto.Change, error) {
 	ret.BeforeSensitivePaths = beforeSensitivePaths
 	ret.AfterSensitivePaths = afterSensitivePaths
 
+	if change.Importing != nil {
+		ret.Importing = &planproto.Importing{
+			Id: change.Importing.ID,
+		}
+
+	}
+	ret.GeneratedConfig = change.GeneratedConfig
+
 	switch change.Action {
 	case plans.NoOp:
 		ret.Action = planproto.Action_NOOP

internal/plans/planfile/tfplan_test.go

@@ -122,6 +122,33 @@ func TestTFPlanRoundTrip(t *testing.T) {
 						}), objTy),
 					},
 				},
+				{
+					Addr: addrs.Resource{
+						Mode: addrs.ManagedResourceMode,
+						Type: "test_thing",
+						Name: "importing",
+					}.Instance(addrs.IntKey(1)).Absolute(addrs.RootModuleInstance),
+					PrevRunAddr: addrs.Resource{
+						Mode: addrs.ManagedResourceMode,
+						Type: "test_thing",
+						Name: "importing",
+					}.Instance(addrs.IntKey(1)).Absolute(addrs.RootModuleInstance),
+					ProviderAddr: addrs.AbsProviderConfig{
+						Provider: addrs.NewDefaultProvider("test"),
+						Module:   addrs.RootModule,
+					},
+					ChangeSrc: plans.ChangeSrc{
+						Action: plans.NoOp,
+						Before: mustNewDynamicValue(cty.ObjectVal(map[string]cty.Value{
+							"id": cty.StringVal("testing"),
+						}), objTy),
+						After: mustNewDynamicValue(cty.ObjectVal(map[string]cty.Value{
+							"id": cty.StringVal("testing"),
+						}), objTy),
+						Importing:       &plans.ImportingSrc{ID: "testing"},
+						GeneratedConfig: "resource \\\"test_thing\\\" \\\"importing\\\" {}",
+					},
+				},
 			},
 		},
 		DriftedResources: []*plans.ResourceInstanceChangeSrc{