do not evaluate module variables during import

We do not currently need to evaluate module variables in order to
import a resource.

This will likely change once we can select the import provider
automatically, and have a more dynamic method for dispatching providers
to module instances. In the meantime we can avoid the evaluation for now
and prevent a certain class of import errors.

terraform/context_import_test.go

@@ -732,6 +732,95 @@ func TestContextImport_multiStateSame(t *testing.T) {
 	}
 }
 
+func TestContextImport_noConfigModuleImport(t *testing.T) {
+	p := testProvider("aws")
+	m := testModuleInline(t, map[string]string{
+		"main.tf": `
+locals {
+  xs = toset(["foo"])
+}
+
+module "a" {
+  for_each = local.xs
+  source   = "./a"
+}
+
+module "b" {
+  for_each = local.xs
+  source   = "./b"
+  y = module.a[each.key].y
+}
+`,
+		"a/main.tf": `
+output "y" {
+  value = "bar"
+}
+`,
+		"b/main.tf": `
+variable "y" {
+  type = string
+}
+
+resource "test_resource" "unused" {
+  value = var.y
+}
+`,
+	})
+
+	p.GetSchemaReturn = &ProviderSchema{
+		Provider: &configschema.Block{
+			Attributes: map[string]*configschema.Attribute{
+				"foo": {Type: cty.String, Optional: true},
+			},
+		},
+		ResourceTypes: map[string]*configschema.Block{
+			"test_resource": {
+				Attributes: map[string]*configschema.Attribute{
+					"id": {Type: cty.String, Computed: true},
+				},
+			},
+		},
+	}
+
+	p.ImportResourceStateResponse = providers.ImportResourceStateResponse{
+		ImportedResources: []providers.ImportedResource{
+			{
+				TypeName: "test_resource",
+				State: cty.ObjectVal(map[string]cty.Value{
+					"id": cty.StringVal("test"),
+				}),
+			},
+		},
+	}
+
+	ctx := testContext2(t, &ContextOpts{
+		Config: m,
+		Providers: map[addrs.Provider]providers.Factory{
+			addrs.NewDefaultProvider("test"): testProviderFuncFixed(p),
+		},
+	})
+
+	state, diags := ctx.Import(&ImportOpts{
+		Targets: []*ImportTarget{
+			&ImportTarget{
+				Addr: addrs.RootModuleInstance.ResourceInstance(
+					addrs.ManagedResourceMode, "test_resource", "test", addrs.NoKey,
+				),
+				ID: "test",
+			},
+		},
+	})
+	if diags.HasErrors() {
+		t.Fatal(diags.ErrWithWarnings())
+	}
+
+	ri := state.ResourceInstance(mustResourceInstanceAddr("test_resource.test"))
+	expected := `{"id":"test"}`
+	if string(ri.Current.AttrsJSON) != expected {
+		t.Fatalf("expected %q, got %q\n", expected, ri.Current.AttrsJSON)
+	}
+}
+
 const testImportStr = `
 aws_instance.foo:
   ID = foo

terraform/node_module_variable.go

@@ -153,7 +153,7 @@ func (n *nodeModuleVariable) Execute(ctx EvalContext, op walkOperation) error {
 	var err error
 
 	switch op {
-	case walkPlan, walkApply, walkDestroy, walkImport:
+	case walkPlan, walkApply, walkDestroy:
 		vals, err = n.EvalModuleCallArgument(ctx, false)
 		if err != nil {
 			return err