Fix spurious grants create for empty grants list on direct engine

.nextchanges/bundles/empty-grants-migrate.md

@@ -0,0 +1 @@
+Fixed the direct deployment engine planning a spurious `create` for an empty `grants: []` list. Terraform records no grants resource for such a list, so `bundle plan` after `bundle deployment migrate` no longer reports an action for it.

acceptance/bundle/invariant/migrate/test.toml

@@ -26,17 +26,6 @@ EnvMatrixExclude.no_cross_resource_ref = ["INPUT_CONFIG=job_cross_resource_ref.y
 # Grant cross-references require the EmbeddedSlice pattern not present in terraform mode.
 EnvMatrixExclude.no_grant_ref = ["INPUT_CONFIG=schema_grant_ref.yml.tmpl"]
 
-# An empty grants list plans a spurious create after migrate: Terraform records no
-# databricks_grants resource for grants: [], so migrate leaves no state entry for the
-# grants node, but the direct plan emits a "create" for it anyway. Found by fuzz testing.
-# The plan check fails with:
-#   Unexpected action='create' for resources.schemas.foo.grants
-#   ...
-#   "resources.schemas.foo.grants": { "action": "create", ... }
-#   Exit code: 10
-# Fixed by https://github.com/databricks/cli/pull/6039; re-enable once that lands.
-EnvMatrixExclude.no_empty_grants = ["INPUT_CONFIG=schema_empty_grants.yml.tmpl"]
-
 # SQL warehouses currently failing with migration with permanent drift. TODO: fix this.
 EnvMatrixExclude.no_sql_warehouse = ["INPUT_CONFIG=sql_warehouse.yml.tmpl"]
 

bundle/direct/bundle_plan.go

@@ -975,6 +975,17 @@ func (b *DeploymentBundle) makePlan(ctx context.Context, configRoot *config.Root
 			return nil, fmt.Errorf("%s: %w", prefix, err)
 		}
 
+		// New nodes only: a node with state must stay in the plan, otherwise emptying it plans nothing.
+		if _, hasState := db.State[node]; !hasState {
+			skip, err := adapter.SkipCreate(newStateConfig)
+			if err != nil {
+				return nil, fmt.Errorf("%s: %w", prefix, err)
+			}
+			if skip {
+				continue
+			}
+		}
+
 		// Note, we're extracting references in input config but resolving them in newState.Config which is PrepareState(inputConfig)
 		// This means input and state must be compatible: input can have more fields, but existing fields should not be moved
 		// This means one cannot refer to fields not present in state (e.g. ${resources.jobs.foo.permissions})

bundle/direct/dresources/README.md

@@ -42,6 +42,10 @@ For resources whose create or update is asynchronous (the resource is not immedi
 
 If the API may return a slice's elements in a different order between calls (e.g., `depends_on` in job tasks, `privileges` in grants), implement `KeyedSlices` to compare elements by a natural key rather than by index. Without this, every deploy after any reordering shows phantom diffs.
 
+## No-op creates: SkipCreate
+
+If a desired state requires no API call to create (e.g. an empty grants list), implement `SkipCreate` and the planner omits the node instead of planning a create. It is only consulted for nodes without a state entry: once state exists the node stays in the plan, so emptying it still plans an update.
+
 ## State backward compatibility
 
 The state struct is serialized to JSON and persisted between deploys. Backward incompatible changes will result in a drift, which depending

bundle/direct/dresources/adapter.go

@@ -56,6 +56,11 @@ type IResource interface {
 	// Example: func (r *ResourceVolume) DoCreate(ctx context.Context, newState *catalog.CreateVolumeRequestContent) (string, *catalog.VolumeInfo, error)
 	DoCreate(ctx context.Context, newState any) (id string, remoteState any, e error)
 
+	// [Optional] SkipCreate reports that creating newState is a no-op, so the planner omits the
+	// node instead of planning a create. Only consulted for nodes without a state entry.
+	// Example: func (*ResourceGrants) SkipCreate(state *GrantsState) bool
+	SkipCreate(newState any) bool
+
 	// [Optional] DoUpdate updates the resource. ID must not change as a result of this operation. Returns optionally remote state.
 	// If remote state is available as part of the operation, return it; otherwise return nil.
 	// Example: func (r *ResourceSchema) DoUpdate(ctx context.Context, id string, newState *catalog.CreateSchema, entry *PlanEntry) (*catalog.SchemaInfo, error)
@@ -103,6 +108,7 @@ type Adapter struct {
 	doCreate     *calladapt.BoundCaller
 
 	// Optional:
+	skipCreate         *calladapt.BoundCaller
 	doUpdate           *calladapt.BoundCaller
 	doUpdateWithID     *calladapt.BoundCaller
 	waitAfterCreate    *calladapt.BoundCaller
@@ -136,6 +142,7 @@ func NewAdapter(typedNil any, resourceType string, client *databricks.WorkspaceC
 		doRefresh:               nil,
 		doDelete:                nil,
 		doCreate:                nil,
+		skipCreate:              nil,
 		doUpdate:                nil,
 		doUpdateWithID:          nil,
 		doResize:                nil,
@@ -205,6 +212,11 @@ func (a *Adapter) initMethods(resource any) error {
 
 	// Optional methods with varying signatures:
 
+	a.skipCreate, err = calladapt.PrepareCall(resource, reflect.TypeFor[IResource](), "SkipCreate")
+	if err != nil {
+		return err
+	}
+
 	a.doUpdate, err = calladapt.PrepareCall(resource, reflect.TypeFor[IResource](), "DoUpdate")
 	if err != nil {
 		return err
@@ -313,6 +325,10 @@ func (a *Adapter) validate() error {
 	}
 	validations = append(validations, "DoCreate remoteState return", a.doCreate.OutTypes[1], remoteType)
 
+	if a.skipCreate != nil {
+		validations = append(validations, "SkipCreate newState", a.skipCreate.InTypes[0], stateType)
+	}
+
 	// Validate DoUpdate: must return (remoteType, error) if implemented
 	if a.doUpdate != nil {
 		validations = append(validations, "DoUpdate newState", a.doUpdate.InTypes[2], stateType)
@@ -470,6 +486,19 @@ func (a *Adapter) DoCreate(ctx context.Context, newState any) (string, any, erro
 	return id, remoteState, nil
 }
 
+// SkipCreate reports whether creating newState is a no-op; false if not implemented.
+func (a *Adapter) SkipCreate(newState any) (bool, error) {
+	if a.skipCreate == nil {
+		return false, nil
+	}
+
+	outs, err := a.skipCreate.Call(newState)
+	if err != nil {
+		return false, err
+	}
+	return outs[0].(bool), nil
+}
+
 // HasDoUpdate returns true if the resource implements DoUpdate method.
 func (a *Adapter) HasDoUpdate() bool {
 	return a.doUpdate != nil

bundle/direct/dresources/grants.go

@@ -76,6 +76,12 @@ func (*ResourceGrants) PrepareState(state *GrantsState) *GrantsState {
 	return state
 }
 
+// SkipCreate reports an empty grants list as a no-op: nothing to grant, and Terraform
+// records no databricks_grants resource for it, so migrated bundles have no state entry.
+func (*ResourceGrants) SkipCreate(state *GrantsState) bool {
+	return len(state.EmbeddedSlice) == 0
+}
+
 func grantKey(x catalog.PrivilegeAssignment) (string, string) {
 	return "principal", x.Principal
 }

bundle/direct/dresources/grants_test.go

@@ -5,6 +5,7 @@ import (
 
 	"github.com/databricks/databricks-sdk-go/service/catalog"
 	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
 )
 
 func TestBuildGrantChanges(t *testing.T) {
@@ -75,6 +76,57 @@ func TestBuildGrantChanges(t *testing.T) {
 	}
 }
 
+// Calls through the adapter so the optional-method wiring is covered too.
+func TestGrantsSkipCreate(t *testing.T) {
+	tests := []struct {
+		name     string
+		state    *GrantsState
+		expected bool
+	}{
+		{
+			name:     "empty grants list",
+			state:    &GrantsState{SecurableType: "schema", EmbeddedSlice: []catalog.PrivilegeAssignment{}},
+			expected: true,
+		},
+		{
+			name:     "unset grants list",
+			state:    &GrantsState{SecurableType: "schema"},
+			expected: true,
+		},
+		{
+			name: "one assignment",
+			state: &GrantsState{
+				SecurableType: "schema",
+				EmbeddedSlice: []catalog.PrivilegeAssignment{
+					{Principal: "alice", Privileges: []catalog.Privilege{catalog.PrivilegeSelect}},
+				},
+			},
+			expected: false,
+		},
+	}
+
+	adapter, err := NewAdapter(SupportedResources["schemas.grants"], "schemas.grants", nil)
+	require.NoError(t, err)
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			skip, err := adapter.SkipCreate(tt.state)
+			require.NoError(t, err)
+			assert.Equal(t, tt.expected, skip)
+		})
+	}
+}
+
+// Resources without SkipCreate always need a create.
+func TestSkipCreateNotImplemented(t *testing.T) {
+	adapter, err := NewAdapter(SupportedResources["schemas"], "schemas", nil)
+	require.NoError(t, err)
+
+	skip, err := adapter.SkipCreate(&catalog.CreateSchema{Name: "myschema"})
+	require.NoError(t, err)
+	assert.False(t, skip)
+}
+
 func TestNormalizeAssignments(t *testing.T) {
 	tests := []struct {
 		name     string