stacks: fix dependency handling in component forget

internal/stacks/stackruntime/apply_test.go

@@ -273,6 +273,196 @@ func TestApply(t *testing.T) {
 				},
 			},
 		},
+		"forget with dependency": {
+			path: "forget_with_dependency",
+			state: stackstate.NewStateBuilder().
+				AddComponentInstance(stackstate.NewComponentInstanceBuilder(mustAbsComponentInstance("component.one")).
+					AddDependent(mustAbsComponent("component.two")).
+					AddInputVariable("value", cty.StringVal("bar")).
+					AddOutputValue("id", cty.StringVal("foo"))).
+				AddResourceInstance(stackstate.NewResourceInstanceBuilder().
+					SetAddr(mustAbsResourceInstanceObject("component.one.testing_resource.resource")).
+					SetProviderAddr(mustDefaultRootProvider("testing")).
+					SetResourceInstanceObjectSrc(states.ResourceInstanceObjectSrc{
+						AttrsJSON: mustMarshalJSONAttrs(map[string]interface{}{
+							"id":    "foo",
+							"value": "bar",
+						}),
+						Status: states.ObjectReady,
+					})).
+				AddComponentInstance(stackstate.NewComponentInstanceBuilder(mustAbsComponentInstance("component.two")).
+					AddDependency(mustAbsComponent("component.one")).
+					AddInputVariable("value", cty.StringVal("foo")).
+					AddOutputValue("id", cty.StringVal("baz"))).
+				AddResourceInstance(stackstate.NewResourceInstanceBuilder().
+					SetAddr(mustAbsResourceInstanceObject("component.two.testing_resource.resource")).
+					SetProviderAddr(mustDefaultRootProvider("testing")).
+					SetResourceInstanceObjectSrc(states.ResourceInstanceObjectSrc{
+						AttrsJSON: mustMarshalJSONAttrs(map[string]interface{}{
+							"id":    "baz",
+							"value": "foo",
+						}),
+						Status: states.ObjectReady,
+					})).
+				Build(),
+			store: stacks_testing_provider.NewResourceStoreBuilder().
+				AddResource("foo", cty.ObjectVal(map[string]cty.Value{
+					"id":    cty.StringVal("foo"),
+					"value": cty.StringVal("bar"),
+				})).
+				AddResource("baz", cty.ObjectVal(map[string]cty.Value{
+					"id":    cty.StringVal("baz"),
+					"value": cty.StringVal("foo"),
+				})).
+				Build(),
+			cycles: []TestCycle{
+				{
+					planMode: plans.NormalMode,
+					wantPlannedDiags: tfdiags.Diagnostics{
+						tfdiags.Sourceless(tfdiags.Warning, "Some objects will no longer be managed by Terraform", `If you apply this plan, Terraform will discard its tracking information for the following objects, but it will not delete them:
+ - testing_resource.resource
+
+After applying this plan, Terraform will no longer manage these objects. You will need to import them into Terraform to manage them again.`),
+					},
+					wantAppliedChanges: []stackstate.AppliedChange{
+						&stackstate.AppliedChangeComponentInstance{
+							ComponentAddr:         mustAbsComponent("component.one"),
+							ComponentInstanceAddr: mustAbsComponentInstance("component.one"),
+							OutputValues: map[addrs.OutputValue]cty.Value{
+								addrs.OutputValue{Name: "id"}: cty.StringVal("foo"),
+							},
+							InputVariables: map[addrs.InputVariable]cty.Value{
+								addrs.InputVariable{Name: "value"}: cty.StringVal("bar"),
+							},
+							Dependents: collections.NewSet(mustAbsComponent("component.two")),
+						},
+						&stackstate.AppliedChangeResourceInstanceObject{
+							ResourceInstanceObjectAddr: mustAbsResourceInstanceObject("component.one.testing_resource.resource"),
+							NewStateSrc: &states.ResourceInstanceObjectSrc{
+								AttrsJSON: mustMarshalJSONAttrs(map[string]interface{}{
+									"id":    "foo",
+									"value": "bar",
+								}),
+								Status:             states.ObjectReady,
+								AttrSensitivePaths: make([]cty.Path, 0),
+							},
+							ProviderConfigAddr: addrs.AbsProviderConfig{
+								Provider: addrs.MustParseProviderSourceString("hashicorp/testing"),
+							},
+							Schema: stacks_testing_provider.TestingResourceSchema,
+						},
+						&stackstate.AppliedChangeComponentInstance{
+							ComponentAddr:         mustAbsComponent("component.two"),
+							ComponentInstanceAddr: mustAbsComponentInstance("component.two"),
+							OutputValues:          map[addrs.OutputValue]cty.Value{},
+							InputVariables: map[addrs.InputVariable]cty.Value{
+								addrs.InputVariable{Name: "value"}: cty.StringVal("foo"),
+							},
+							Dependencies: collections.NewSet(mustAbsComponent("component.one")),
+						},
+						&stackstate.AppliedChangeResourceInstanceObject{
+							ResourceInstanceObjectAddr: mustAbsResourceInstanceObject("component.two.testing_resource.resource"),
+							NewStateSrc:                nil, // Resource is forgotten
+							ProviderConfigAddr: addrs.AbsProviderConfig{
+								Provider: addrs.MustParseProviderSourceString("hashicorp/testing"),
+							},
+						},
+					},
+				},
+			},
+		},
+		"forget with dependency on component to forget": {
+			path: "forget_with_dependency_to_forget",
+			state: stackstate.NewStateBuilder().
+				AddComponentInstance(stackstate.NewComponentInstanceBuilder(mustAbsComponentInstance("component.one")).
+					AddDependent(mustAbsComponent("component.two")).
+					AddInputVariable("value", cty.StringVal("bar")).
+					AddOutputValue("id", cty.StringVal("foo"))).
+				AddResourceInstance(stackstate.NewResourceInstanceBuilder().
+					SetAddr(mustAbsResourceInstanceObject("component.one.testing_resource.resource")).
+					SetProviderAddr(mustDefaultRootProvider("testing")).
+					SetResourceInstanceObjectSrc(states.ResourceInstanceObjectSrc{
+						AttrsJSON: mustMarshalJSONAttrs(map[string]interface{}{
+							"id":    "foo",
+							"value": "bar",
+						}),
+						Status: states.ObjectReady,
+					})).
+				AddComponentInstance(stackstate.NewComponentInstanceBuilder(mustAbsComponentInstance("component.two")).
+					AddDependency(mustAbsComponent("component.one")).
+					AddInputVariable("value", cty.StringVal("foo")).
+					AddOutputValue("id", cty.StringVal("baz"))).
+				AddResourceInstance(stackstate.NewResourceInstanceBuilder().
+					SetAddr(mustAbsResourceInstanceObject("component.two.testing_resource.resource")).
+					SetProviderAddr(mustDefaultRootProvider("testing")).
+					SetResourceInstanceObjectSrc(states.ResourceInstanceObjectSrc{
+						AttrsJSON: mustMarshalJSONAttrs(map[string]interface{}{
+							"id":    "baz",
+							"value": "foo",
+						}),
+						Status: states.ObjectReady,
+					})).
+				Build(),
+			store: stacks_testing_provider.NewResourceStoreBuilder().
+				AddResource("foo", cty.ObjectVal(map[string]cty.Value{
+					"id":    cty.StringVal("foo"),
+					"value": cty.StringVal("bar"),
+				})).
+				AddResource("baz", cty.ObjectVal(map[string]cty.Value{
+					"id":    cty.StringVal("baz"),
+					"value": cty.StringVal("foo"),
+				})).
+				Build(),
+			cycles: []TestCycle{
+				{
+					planMode: plans.NormalMode,
+					wantPlannedDiags: tfdiags.Diagnostics{
+						tfdiags.Sourceless(tfdiags.Warning, "Some objects will no longer be managed by Terraform", `If you apply this plan, Terraform will discard its tracking information for the following objects, but it will not delete them:
+ - testing_resource.resource
+
+After applying this plan, Terraform will no longer manage these objects. You will need to import them into Terraform to manage them again.`),
+						tfdiags.Sourceless(tfdiags.Warning, "Some objects will no longer be managed by Terraform", `If you apply this plan, Terraform will discard its tracking information for the following objects, but it will not delete them:
+ - testing_resource.resource
+
+After applying this plan, Terraform will no longer manage these objects. You will need to import them into Terraform to manage them again.`),
+					},
+					wantAppliedChanges: []stackstate.AppliedChange{
+						&stackstate.AppliedChangeComponentInstance{
+							ComponentAddr:         mustAbsComponent("component.one"),
+							ComponentInstanceAddr: mustAbsComponentInstance("component.one"),
+							OutputValues:          map[addrs.OutputValue]cty.Value{}, // No output being read, we rely on the plan data
+							InputVariables: map[addrs.InputVariable]cty.Value{
+								addrs.InputVariable{Name: "value"}: cty.StringVal("bar"),
+							},
+							Dependents: collections.NewSet(mustAbsComponent("component.two")),
+						},
+						&stackstate.AppliedChangeResourceInstanceObject{
+							ResourceInstanceObjectAddr: mustAbsResourceInstanceObject("component.one.testing_resource.resource"),
+							NewStateSrc:                nil, // Resource is forgotten
+							ProviderConfigAddr: addrs.AbsProviderConfig{
+								Provider: addrs.MustParseProviderSourceString("hashicorp/testing"),
+							},
+						},
+						&stackstate.AppliedChangeComponentInstance{
+							ComponentAddr:         mustAbsComponent("component.two"),
+							ComponentInstanceAddr: mustAbsComponentInstance("component.two"),
+							OutputValues:          map[addrs.OutputValue]cty.Value{},
+							InputVariables: map[addrs.InputVariable]cty.Value{
+								addrs.InputVariable{Name: "value"}: cty.StringVal("foo"),
+							},
+							Dependencies: collections.NewSet(mustAbsComponent("component.one")),
+						},
+						&stackstate.AppliedChangeResourceInstanceObject{
+							ResourceInstanceObjectAddr: mustAbsResourceInstanceObject("component.two.testing_resource.resource"),
+							NewStateSrc:                nil, // Resource is forgotten
+							ProviderConfigAddr: addrs.AbsProviderConfig{
+								Provider: addrs.MustParseProviderSourceString("hashicorp/testing"),
+							},
+						},
+					},
+				},
+			},
+		},
 	}
 
 	for name, tc := range tcs {

internal/stacks/stackruntime/helper_test.go

@@ -468,7 +468,12 @@ func diagnosticSortFunc(diags tfdiags.Diagnostics) func(i, j int) bool {
 		if !cmp.Equal(id.Description(), jd.Description()) {
 			return sortDescription(id.Description(), jd.Description())
 		}
-		return sortRange(id.Source().Subject, jd.Source().Subject)
+		if id.Source().Subject != nil && jd.Source().Subject != nil {
+
+			return sortRange(id.Source().Subject, jd.Source().Subject)
+		}
+
+		return false
 	}
 }
 

internal/stacks/stackruntime/internal/stackeval/component_instance.go

@@ -519,7 +519,8 @@ func (c *ComponentInstance) ResultValue(ctx context.Context, phase EvalPhase) ct
 				// Weird, but we'll tolerate it.
 				return cty.DynamicVal
 			}
-			if ourPlan.PlannedAction == plans.Delete {
+
+			if ourPlan.PlannedAction == plans.Delete || ourPlan.PlannedAction == plans.Forget {
 				// In this case our result was already decided during the
 				// planning phase, because we can't block on anything else
 				// here to make sure we don't create a self-dependency

internal/stacks/stackruntime/internal/stackeval/main_apply.go

@@ -182,7 +182,7 @@ func ApplyPlan(ctx context.Context, config *stackconfig.Config, plan *stackplan.
 
 						var waitForComponents collections.Set[stackaddrs.AbsComponent]
 						var waitForRemoveds collections.Set[stackaddrs.AbsComponent]
-						if action == plans.Delete {
+						if action == plans.Delete || action == plans.Forget {
 							// If the effect of this apply will be to destroy this
 							// component instance then we need to wait for all
 							// of our dependents to be destroyed first, because

internal/stacks/stackruntime/testdata/mainbundle/test/forget_with_dependency/forget_with_dependency.tf

@@ -0,0 +1,11 @@
+variable "value" {
+  type = string
+}
+
+resource "testing_resource" "resource" {
+  value = var.value
+}
+
+output "id" {
+  value = testing_resource.resource.id
+}

internal/stacks/stackruntime/testdata/mainbundle/test/forget_with_dependency/forget_with_dependency.tfstack.hcl

@@ -0,0 +1,33 @@
+required_providers {
+  testing = {
+    source  = "hashicorp/testing"
+    version = "0.1.0"
+  }
+}
+
+provider "testing" "default" {}
+
+component "one" {
+  source = "./"
+
+  providers = {
+    testing = provider.testing.default
+  }
+
+  inputs = {
+    value = "bar"
+  }
+}
+
+removed {
+  source = "./"
+  from = component.two
+
+  providers = {
+    testing = provider.testing.default
+  }
+
+  lifecycle {
+    destroy = false
+  }
+}

internal/stacks/stackruntime/testdata/mainbundle/test/forget_with_dependency_to_forget/forget_with_dependency_to_forget.tf

@@ -0,0 +1,11 @@
+variable "value" {
+  type = string
+}
+
+resource "testing_resource" "resource" {
+  value = var.value
+}
+
+output "id" {
+  value = testing_resource.resource.id
+}

internal/stacks/stackruntime/testdata/mainbundle/test/forget_with_dependency_to_forget/forget_with_dependency_to_forget.tfstack.hcl

@@ -0,0 +1,34 @@
+required_providers {
+  testing = {
+    source  = "hashicorp/testing"
+    version = "0.1.0"
+  }
+}
+
+provider "testing" "default" {}
+
+removed {
+  source = "./"
+  from = component.one
+  
+  providers = {
+    testing = provider.testing.default
+  }
+
+  lifecycle {
+      destroy = false
+    }
+}
+
+removed {
+  source = "./"
+  from = component.two
+
+  providers = {
+    testing = provider.testing.default
+  }
+
+  lifecycle {
+    destroy = false
+  }
+}