remove stale dependencies on `state mv`

Clear any Dependencies if there is an entry matching a `state mv` from
address. While stale dependencies won't directly effect any current
operations, clearing the list will allow them to be recreated in their
entirety during refresh. This will help future releases that may rely
solely on the pre-calculated dependencies for destruction ordering.

command/command_test.go

@@ -879,3 +879,11 @@ func normalizeJSON(t *testing.T, src []byte) string {
 	}
 	return buf.String()
 }
+
+func mustResourceAddr(s string) addrs.AbsResource {
+	addr, diags := addrs.ParseAbsResourceStr(s)
+	if diags.HasErrors() {
+		panic(diags.Err())
+	}
+	return addr
+}

command/state_mv.go

@@ -314,6 +314,28 @@ func (c *StateMvCommand) Run(args []string) int {
 				fmt.Sprintf("Cannot move %s: Terraform doesn't know how to move this object.", rawAddrFrom),
 			))
 		}
+
+		// Look for any dependencies that may be effected and
+		// remove them to ensure they are recreated in full.
+		for _, mod := range stateTo.Modules {
+			for _, res := range mod.Resources {
+				for _, ins := range res.Instances {
+					if ins.Current == nil {
+						continue
+					}
+
+					for _, dep := range ins.Current.Dependencies {
+						// check both directions here, since we may be moving
+						// an instance which is in a resource, or a module
+						// which can contain a resource.
+						if dep.TargetContains(rawAddrFrom) || rawAddrFrom.TargetContains(dep) {
+							ins.Current.Dependencies = nil
+							break
+						}
+					}
+				}
+			}
+		}
 	}
 
 	if dryRun {

command/state_mv_test.go

@@ -38,6 +38,7 @@ func TestStateMv(t *testing.T) {
 			&states.ResourceInstanceObjectSrc{
 				AttrsJSON:    []byte(`{"id":"foo","foo":"value","bar":"value"}`),
 				Status:       states.ObjectReady,
+				Dependencies: []addrs.AbsResource{mustResourceAddr("test_instance.foo")},
 			},
 			addrs.ProviderConfig{Type: addrs.NewLegacyProvider("test")}.Absolute(addrs.RootModuleInstance),
 		)
@@ -98,6 +99,7 @@ func TestStateMv_resourceToInstance(t *testing.T) {
 			&states.ResourceInstanceObjectSrc{
 				AttrsJSON:    []byte(`{"id":"foo","foo":"value","bar":"value"}`),
 				Status:       states.ObjectReady,
+				Dependencies: []addrs.AbsResource{mustResourceAddr("test_instance.foo")},
 			},
 			addrs.ProviderConfig{Type: addrs.NewLegacyProvider("test")}.Absolute(addrs.RootModuleInstance),
 		)
@@ -447,6 +449,7 @@ func TestStateMv_backupExplicit(t *testing.T) {
 			&states.ResourceInstanceObjectSrc{
 				AttrsJSON:    []byte(`{"id":"foo","foo":"value","bar":"value"}`),
 				Status:       states.ObjectReady,
+				Dependencies: []addrs.AbsResource{mustResourceAddr("test_instance.foo")},
 			},
 			addrs.ProviderConfig{Type: addrs.NewLegacyProvider("test")}.Absolute(addrs.RootModuleInstance),
 		)
@@ -897,42 +900,40 @@ func TestStateMv_toNewModule(t *testing.T) {
 	}
 	testStateOutput(t, stateOutPath2, testStateMvModuleNewModule_stateOut)
 }
+
 func TestStateMv_withinBackend(t *testing.T) {
 	td := tempDir(t)
 	copy.CopyDir(testFixturePath("backend-unchanged"), td)
 	defer os.RemoveAll(td)
 	defer testChdir(t, td)()
 
-	state := &terraform.State{
-		Modules: []*terraform.ModuleState{
-			&terraform.ModuleState{
-				Path: []string{"root"},
-				Resources: map[string]*terraform.ResourceState{
-					"test_instance.foo": &terraform.ResourceState{
+	state := states.BuildState(func(s *states.SyncState) {
+		s.SetResourceInstanceCurrent(
+			addrs.Resource{
+				Mode: addrs.ManagedResourceMode,
 				Type: "test_instance",
-						Primary: &terraform.InstanceState{
-							ID: "bar",
-							Attributes: map[string]string{
-								"foo": "value",
-								"bar": "value",
+				Name: "foo",
+			}.Instance(addrs.NoKey).Absolute(addrs.RootModuleInstance),
+			&states.ResourceInstanceObjectSrc{
+				AttrsJSON: []byte(`{"id":"bar","foo":"value","bar":"value"}`),
+				Status:    states.ObjectReady,
 			},
-						},
-					},
-
-					"test_instance.baz": &terraform.ResourceState{
+			addrs.ProviderConfig{Type: addrs.NewLegacyProvider("test")}.Absolute(addrs.RootModuleInstance),
+		)
+		s.SetResourceInstanceCurrent(
+			addrs.Resource{
+				Mode: addrs.ManagedResourceMode,
 				Type: "test_instance",
-						Primary: &terraform.InstanceState{
-							ID: "foo",
-							Attributes: map[string]string{
-								"foo": "value",
-								"bar": "value",
+				Name: "baz",
+			}.Instance(addrs.NoKey).Absolute(addrs.RootModuleInstance),
+			&states.ResourceInstanceObjectSrc{
+				AttrsJSON:    []byte(`{"id":"foo","foo":"value","bar":"value"}`),
+				Status:       states.ObjectReady,
+				Dependencies: []addrs.AbsResource{mustResourceAddr("test_instance.foo")},
 			},
-						},
-					},
-				},
-			},
-		},
-	}
+			addrs.ProviderConfig{Type: addrs.NewLegacyProvider("test")}.Absolute(addrs.RootModuleInstance),
+		)
+	})
 
 	// the local backend state file is "foo"
 	statePath := "local-state.tfstate"
@@ -944,7 +945,7 @@ func TestStateMv_withinBackend(t *testing.T) {
 	}
 	defer f.Close()
 
-	if err := terraform.WriteState(state, f); err != nil {
+	if err := writeStateForTesting(state, f); err != nil {
 		t.Fatal(err)
 	}
 
@@ -1057,6 +1058,9 @@ test_instance.baz:
   provider = provider.test
   bar = value
   foo = value
+
+  Dependencies:
+    test_instance.foo
 test_instance.foo:
   ID = bar
   provider = provider.test