lookup(): only treat map as unknown if it is wholly unknown

Fix for issue #26320 - this allows us to derive known values
from partially known maps where we can, and may prevent unnecessary
destroy/rebuild cycles during apply in some cases.

command/e2etest/automation_test.go

@@ -56,8 +56,8 @@ func TestPlanApplyInAutomation(t *testing.T) {
 		t.Fatalf("unexpected plan error: %s\nstderr:\n%s", err, stderr)
 	}
 
-	if !strings.Contains(stdout, "1 to add, 0 to change, 0 to destroy") {
-		t.Errorf("incorrect plan tally; want 1 to add:\n%s", stdout)
+	if !strings.Contains(stdout, "2 to add, 0 to change, 0 to destroy") {
+		t.Errorf("incorrect plan tally; want 2 to add:\n%s", stdout)
 	}
 
 	// Because we're running with TF_IN_AUTOMATION set, we should not see
@@ -73,12 +73,13 @@ func TestPlanApplyInAutomation(t *testing.T) {
 
 	// stateResources := plan.Changes.Resources
 	diffResources := plan.Changes.Resources
-	if len(diffResources) != 1 {
+	if len(diffResources) != 2 {
 		t.Errorf("incorrect number of resources in plan")
 	}
 
 	expected := map[string]plans.Action{
-		"null_resource.test": plans.Create,
+		"null_resource.id_known_after_apply": plans.Create,
+		"null_resource.test":                 plans.Create,
 	}
 
 	for _, r := range diffResources {
@@ -97,8 +98,8 @@ func TestPlanApplyInAutomation(t *testing.T) {
 		t.Fatalf("unexpected apply error: %s\nstderr:\n%s", err, stderr)
 	}
 
-	if !strings.Contains(stdout, "Resources: 1 added, 0 changed, 0 destroyed") {
-		t.Errorf("incorrect apply tally; want 1 added:\n%s", stdout)
+	if !strings.Contains(stdout, "Resources: 2 added, 0 changed, 0 destroyed") {
+		t.Errorf("incorrect apply tally; want 2 added:\n%s", stdout)
 	}
 
 	state, err := tf.LocalState()
@@ -115,6 +116,7 @@ func TestPlanApplyInAutomation(t *testing.T) {
 
 	wantResources := []string{
 		"data.template_file.test",
+		"null_resource.id_known_after_apply",
 		"null_resource.test",
 	}
 
@@ -164,8 +166,8 @@ func TestAutoApplyInAutomation(t *testing.T) {
 		t.Fatalf("unexpected apply error: %s\nstderr:\n%s", err, stderr)
 	}
 
-	if !strings.Contains(stdout, "Resources: 1 added, 0 changed, 0 destroyed") {
-		t.Errorf("incorrect apply tally; want 1 added:\n%s", stdout)
+	if !strings.Contains(stdout, "Resources: 2 added, 0 changed, 0 destroyed") {
+		t.Errorf("incorrect apply tally; want 2 added:\n%s", stdout)
 	}
 
 	state, err := tf.LocalState()
@@ -182,6 +184,7 @@ func TestAutoApplyInAutomation(t *testing.T) {
 
 	wantResources := []string{
 		"data.template_file.test",
+		"null_resource.id_known_after_apply",
 		"null_resource.test",
 	}
 
@@ -231,8 +234,8 @@ func TestPlanOnlyInAutomation(t *testing.T) {
 		t.Fatalf("unexpected plan error: %s\nstderr:\n%s", err, stderr)
 	}
 
-	if !strings.Contains(stdout, "1 to add, 0 to change, 0 to destroy") {
-		t.Errorf("incorrect plan tally; want 1 to add:\n%s", stdout)
+	if !strings.Contains(stdout, "2 to add, 0 to change, 0 to destroy") {
+		t.Errorf("incorrect plan tally; want 2 to add:\n%s", stdout)
 	}
 
 	// Because we're running with TF_IN_AUTOMATION set, we should not see

command/e2etest/primary_test.go

@@ -55,8 +55,8 @@ func TestPrimarySeparatePlan(t *testing.T) {
 		t.Fatalf("unexpected plan error: %s\nstderr:\n%s", err, stderr)
 	}
 
-	if !strings.Contains(stdout, "1 to add, 0 to change, 0 to destroy") {
-		t.Errorf("incorrect plan tally; want 1 to add:\n%s", stdout)
+	if !strings.Contains(stdout, "2 to add, 0 to change, 0 to destroy") {
+		t.Errorf("incorrect plan tally; want 2 to add:\n%s", stdout)
 	}
 
 	if !strings.Contains(stdout, "This plan was saved to: tfplan") {
@@ -66,18 +66,24 @@ func TestPrimarySeparatePlan(t *testing.T) {
 		t.Errorf("missing next-step instruction in plan output\n%s", stdout)
 	}
 
+	// regression test for GitHub issue #26320
+	if !strings.Contains(stdout, "\"greeting\" = \"Hello, world\"\n") {
+		t.Errorf("regression: known value for triggers[\"greeting\"] incorrectly marked as unknown in plan output\n%s", stdout)
+	}
+
 	plan, err := tf.Plan("tfplan")
 	if err != nil {
 		t.Fatalf("failed to read plan file: %s", err)
 	}
 
 	diffResources := plan.Changes.Resources
-	if len(diffResources) != 1 {
+	if len(diffResources) != 2 {
 		t.Errorf("incorrect number of resources in plan")
 	}
 
 	expected := map[string]plans.Action{
-		"null_resource.test": plans.Create,
+		"null_resource.id_known_after_apply": plans.Create,
+		"null_resource.test":                 plans.Create,
 	}
 
 	for _, r := range diffResources {
@@ -96,8 +102,8 @@ func TestPrimarySeparatePlan(t *testing.T) {
 		t.Fatalf("unexpected apply error: %s\nstderr:\n%s", err, stderr)
 	}
 
-	if !strings.Contains(stdout, "Resources: 1 added, 0 changed, 0 destroyed") {
-		t.Errorf("incorrect apply tally; want 1 added:\n%s", stdout)
+	if !strings.Contains(stdout, "Resources: 2 added, 0 changed, 0 destroyed") {
+		t.Errorf("incorrect apply tally; want 2 added:\n%s", stdout)
 	}
 
 	state, err := tf.LocalState()
@@ -114,6 +120,7 @@ func TestPrimarySeparatePlan(t *testing.T) {
 
 	wantResources := []string{
 		"data.template_file.test",
+		"null_resource.id_known_after_apply",
 		"null_resource.test",
 	}
 
@@ -127,8 +134,8 @@ func TestPrimarySeparatePlan(t *testing.T) {
 		t.Fatalf("unexpected destroy error: %s\nstderr:\n%s", err, stderr)
 	}
 
-	if !strings.Contains(stdout, "Resources: 1 destroyed") {
-		t.Errorf("incorrect destroy tally; want 1 destroyed:\n%s", stdout)
+	if !strings.Contains(stdout, "Resources: 2 destroyed") {
+		t.Errorf("incorrect destroy tally; want 2 destroyed:\n%s", stdout)
 	}
 
 	state, err = tf.LocalState()

command/e2etest/testdata/full-workflow-null/main.tf

@@ -11,9 +11,19 @@ data "template_file" "test" {
   }
 }
 
+resource "null_resource" "id_known_after_apply" {
+}
+
+locals {
+  map_with_unknown_value = tomap({
+    foo = null_resource.id_known_after_apply.id
+    greeting = "${data.template_file.test.rendered}"
+  })
+}
+
 resource "null_resource" "test" {
   triggers = {
-    greeting = "${data.template_file.test.rendered}"
+    greeting = lookup(local.map_with_unknown_value, "greeting")
   }
 }
 

lang/funcs/collection.go

@@ -315,7 +315,7 @@ var LookupFunc = function.New(&function.Spec{
 		mapVar := args[0]
 		lookupKey := args[1].AsString()
 
-		if !mapVar.IsWhollyKnown() {
+		if !mapVar.IsKnown() {
 			return cty.UnknownVal(retType), nil
 		}