RemovePlannedResourceInstanceObjects during import

internal/terraform/context_import.go

@@ -82,6 +82,11 @@ func (c *Context) Import(config *configs.Config, prevRunState *states.State, opt
 		return state, diags
 	}
 
+	// Data sources which could not be read during the import plan will be
+	// unknown. We need to strip those objects out so that the state can be
+	// serialized.
+	walker.State.RemovePlannedResourceInstanceObjects()
+
 	newState := walker.State.Close()
 	return newState, diags
 }

internal/terraform/context_import_test.go

@@ -430,7 +430,24 @@ func TestContextImport_providerConfigResources(t *testing.T) {
 
 func TestContextImport_refresh(t *testing.T) {
 	p := testProvider("aws")
-	m := testModule(t, "import-provider")
+	m := testModuleInline(t, map[string]string{
+		"main.tf": `
+provider "aws" {
+  foo = "bar"
+}
+
+resource "aws_instance" "foo" {
+}
+
+
+// we are only importing aws_instance.foo, so these resources will be unknown
+resource "aws_instance" "bar" {
+}
+data "aws_data_source" "bar" {
+  foo = aws_instance.bar.id
+}
+`})
+
 	ctx := testContext2(t, &ContextOpts{
 		Providers: map[addrs.Provider]providers.Factory{
 			addrs.NewDefaultProvider("aws"): testProviderFuncFixed(p),
@@ -448,6 +465,13 @@ func TestContextImport_refresh(t *testing.T) {
 		},
 	}
 
+	p.ReadDataSourceResponse = &providers.ReadDataSourceResponse{
+		State: cty.ObjectVal(map[string]cty.Value{
+			"id":  cty.StringVal("id"),
+			"foo": cty.UnknownVal(cty.String),
+		}),
+	}
+
 	p.ReadResourceFn = nil
 
 	p.ReadResourceResponse = &providers.ReadResourceResponse{
@@ -471,6 +495,10 @@ func TestContextImport_refresh(t *testing.T) {
 		t.Fatalf("unexpected errors: %s", diags.Err())
 	}
 
+	if d := state.ResourceInstance(mustResourceInstanceAddr("data.aws_data_source.bar")); d != nil {
+		t.Errorf("data.aws_data_source.bar has a status of ObjectPlanned and should not be in the state\ngot:%#v\n", d.Current)
+	}
+
 	actual := strings.TrimSpace(state.String())
 	expected := strings.TrimSpace(testImportRefreshStr)
 	if actual != expected {