Merge pull request #35330 from hashicorp/jbardin/module-import-diags

Missing import target in module should error

internal/terraform/context_import_test.go

@@ -1031,6 +1031,47 @@ func TestContextImport_33572(t *testing.T) {
 	}
 }
 
+// Missing import target should produce an error
+func TestContextImport_missingModuleImport(t *testing.T) {
+	p := testProvider("test")
+	m := testModuleInline(t, map[string]string{
+		"main.tf": `
+locals {
+  xs = toset(["foo"])
+}
+
+module "a" {
+  for_each = local.xs
+  source   = "./a"
+}
+
+import {
+	to = module.WRONG.test_resource.x
+	id = "id"
+}
+`,
+		"a/main.tf": `
+resource "test_resource" "x" {
+  value = "z"
+}
+`,
+	})
+
+	ctx := testContext2(t, &ContextOpts{
+		Providers: map[addrs.Provider]providers.Factory{
+			addrs.NewDefaultProvider("test"): testProviderFuncFixed(p),
+		},
+	})
+
+	_, diags := ctx.Plan(m, states.NewState(), DefaultPlanOpts)
+	if !diags.HasErrors() {
+		t.Fatal("expected missing import target error")
+	}
+	if !strings.Contains(diags.Err().Error(), "Configuration for import target does not exist") {
+		t.Fatalf("incorrect error for missing import target: %s\n", diags.Err())
+	}
+}
+
 const testImportStr = `
 aws_instance.foo:
   ID = foo

internal/terraform/transform_config.go

@@ -62,6 +62,10 @@ func (t *ConfigTransformer) Transform(g *Graph) error {
 		return nil
 	}
 
+	if err := t.validateImportTargets(); err != nil {
+		return err
+	}
+
 	// Start the transformation process
 	return t.transform(g, t.Config)
 }
@@ -173,13 +177,6 @@ func (t *ConfigTransformer) transformSingle(g *Graph, config *configs.Config) er
 
 	// If any import targets were not claimed by resources and we are
 	// generating configuration, then let's add them into the graph now.
-
-	// TODO: use diagnostics to collect detailed errors for now, even though we
-	// can only return an error from here. This gives the user more immediate
-	// feedback, rather than waiting an unknown amount of time for the plan to
-	// fail.
-	var diags tfdiags.Diagnostics
-
 	for _, i := range importTargets {
 		if path.IsRoot() {
 			// If we have a single instance import target in the root module, we
@@ -212,8 +209,49 @@ func (t *ConfigTransformer) transformSingle(g *Graph, config *configs.Config) er
 				g.Add(node)
 				continue
 			}
+		}
+	}
+	return nil
+}
+
+// validateImportTargets ensures that the import target resources exist in the
+// configuration. We do this here rather than statically during config loading
+// to have any CLI imports included, and to provide feedback about possible
+// config generation.
+func (t *ConfigTransformer) validateImportTargets() error {
+	var diags tfdiags.Diagnostics
+
+	for _, i := range t.importTargets {
+		var toResource addrs.ConfigResource
+		switch {
+		case i.Config != nil:
+			toResource = i.Config.ToResource
+		default:
+			toResource = i.LegacyAddr.ConfigResource()
+		}
+
+		moduleCfg := t.Config.Root.Descendent(toResource.Module)
+		if moduleCfg != nil {
+			res := moduleCfg.Module.ResourceByAddr(toResource.Resource)
+			if res != nil {
+				// the target config exists, which is all we're looking for at this point.
+				continue
+			}
+		}
+
+		if toResource.Module.IsRoot() {
+			var toDiags tfdiags.Diagnostics
+			traversal, hd := hcl.AbsTraversalForExpr(i.Config.To)
+			toDiags = toDiags.Append(hd)
+			to, td := addrs.ParseAbsResourceInstance(traversal)
+			toDiags = toDiags.Append(td)
+			canGenerate := !toDiags.HasErrors() && to.Resource.Key == addrs.NoKey
+
+			if t.generateConfigPathForImportTargets != "" {
+				if canGenerate {
+					continue
+				}
 
-			if t.generateConfigPathForImportTargets != "" && !canGenerate {
 				diags = diags.Append(&hcl.Diagnostic{
 					Severity: hcl.DiagError,
 					Summary:  "Cannot generate configuration",