feat: add previousValue to privacy policy context for updates (#232)

packages/entity-example/src/entities/AllowIfUserOwnerPrivacyRule.ts

@@ -35,7 +35,13 @@ export default class AllowIfUserOwnerPrivacyRule<
   async evaluateAsync(
     viewerContext: ExampleViewerContext,
     _queryContext: EntityQueryContext,
-    _evaluationContext: EntityPrivacyPolicyEvaluationContext,
+    _evaluationContext: EntityPrivacyPolicyEvaluationContext<
+      TFields,
+      TID,
+      ExampleViewerContext,
+      TEntity,
+      TSelectedFields
+    >,
     entity: TEntity
   ): Promise<RuleEvaluationResult> {
     if (viewerContext.isUserViewerContext()) {

packages/entity/src/EntityAssociationLoader.ts

@@ -74,7 +74,7 @@ export default class EntityAssociationLoader<
       .getViewerContext()
       .getViewerScopedEntityCompanionForClass(associatedEntityClass)
       .getLoaderFactory()
-      .forLoad(queryContext, { cascadingDeleteCause: null });
+      .forLoad(queryContext, { previousValue: null, cascadingDeleteCause: null });
 
     return (await loader.loadByIDAsync(associatedEntityID as unknown as TAssociatedID)) as Result<
       null extends TFields[TIdentifyingField] ? TAssociatedEntity | null : TAssociatedEntity
@@ -128,7 +128,7 @@ export default class EntityAssociationLoader<
       .getViewerContext()
       .getViewerScopedEntityCompanionForClass(associatedEntityClass)
       .getLoaderFactory()
-      .forLoad(queryContext, { cascadingDeleteCause: null });
+      .forLoad(queryContext, { previousValue: null, cascadingDeleteCause: null });
     return await loader.loadManyByFieldEqualingAsync(
       associatedEntityFieldContainingThisID,
       thisID as any
@@ -185,7 +185,7 @@ export default class EntityAssociationLoader<
       .getViewerContext()
       .getViewerScopedEntityCompanionForClass(associatedEntityClass)
       .getLoaderFactory()
-      .forLoad(queryContext, { cascadingDeleteCause: null });
+      .forLoad(queryContext, { previousValue: null, cascadingDeleteCause: null });
     return await loader.loadByFieldEqualingAsync(
       associatedEntityLookupByField,
       associatedFieldValue as any
@@ -243,7 +243,7 @@ export default class EntityAssociationLoader<
       .getViewerContext()
       .getViewerScopedEntityCompanionForClass(associatedEntityClass)
       .getLoaderFactory()
-      .forLoad(queryContext, { cascadingDeleteCause: null });
+      .forLoad(queryContext, { previousValue: null, cascadingDeleteCause: null });
     return await loader.loadManyByFieldEqualingAsync(
       associatedEntityLookupByField,
       associatedFieldValue as any

packages/entity/src/EntityLoader.ts

@@ -43,7 +43,13 @@ export default class EntityLoader<
   constructor(
     private readonly viewerContext: TViewerContext,
     private readonly queryContext: EntityQueryContext,
-    private readonly privacyPolicyEvaluationContext: EntityPrivacyPolicyEvaluationContext,
+    private readonly privacyPolicyEvaluationContext: EntityPrivacyPolicyEvaluationContext<
+      TFields,
+      TID,
+      TViewerContext,
+      TEntity,
+      TSelectedFields
+    >,
     private readonly entityConfiguration: EntityConfiguration<TFields>,
     private readonly entityClass: IEntityClass<
       TFields,

packages/entity/src/EntityLoaderFactory.ts

@@ -45,7 +45,13 @@ export default class EntityLoaderFactory<
   forLoad(
     viewerContext: TViewerContext,
     queryContext: EntityQueryContext,
-    privacyPolicyEvaluationContext: EntityPrivacyPolicyEvaluationContext
+    privacyPolicyEvaluationContext: EntityPrivacyPolicyEvaluationContext<
+      TFields,
+      TID,
+      TViewerContext,
+      TEntity,
+      TSelectedFields
+    >
   ): EntityLoader<TFields, TID, TViewerContext, TEntity, TPrivacyPolicy, TSelectedFields> {
     return new EntityLoader(
       viewerContext,

packages/entity/src/EntityMutator.ts

@@ -212,6 +212,7 @@ export class CreateMutator<
     this.validateFields(this.fieldsForEntity);
 
     const entityLoader = this.entityLoaderFactory.forLoad(this.viewerContext, queryContext, {
+      previousValue: null,
       cascadingDeleteCause: null,
     });
 
@@ -224,7 +225,7 @@ export class CreateMutator<
       this.privacyPolicy.authorizeCreateAsync(
         this.viewerContext,
         queryContext,
-        { cascadingDeleteCause: null },
+        { previousValue: null, cascadingDeleteCause: null },
         temporaryEntityForPrivacyCheck,
         this.metricsAdapter
       )
@@ -423,6 +424,7 @@ export class UpdateMutator<
     this.validateFields(this.updatedFields);
 
     const entityLoader = this.entityLoaderFactory.forLoad(this.viewerContext, queryContext, {
+      previousValue: this.originalEntity,
       cascadingDeleteCause,
     });
 
@@ -431,7 +433,7 @@ export class UpdateMutator<
       this.privacyPolicy.authorizeUpdateAsync(
         this.viewerContext,
         queryContext,
-        { cascadingDeleteCause },
+        { previousValue: this.originalEntity, cascadingDeleteCause },
         entityAboutToBeUpdated,
         this.metricsAdapter
       )
@@ -633,7 +635,7 @@ export class DeleteMutator<
       this.privacyPolicy.authorizeDeleteAsync(
         this.viewerContext,
         queryContext,
-        { cascadingDeleteCause },
+        { previousValue: null, cascadingDeleteCause },
         this.entity,
         this.metricsAdapter
       )
@@ -671,6 +673,7 @@ export class DeleteMutator<
     }
 
     const entityLoader = this.entityLoaderFactory.forLoad(this.viewerContext, queryContext, {
+      previousValue: null,
       cascadingDeleteCause,
     });
     queryContext.appendPostCommitInvalidationCallback(
@@ -774,7 +777,10 @@ export class DeleteMutator<
             }
 
             const inboundReferenceEntities = await loaderFactory
-              .forLoad(queryContext, { cascadingDeleteCause: newCascadingDeleteCause })
+              .forLoad(queryContext, {
+                previousValue: null,
+                cascadingDeleteCause: newCascadingDeleteCause,
+              })
               .enforcing()
               .loadManyByFieldEqualingAsync(
                 fieldName,

packages/entity/src/EntityPrivacyPolicy.ts

@@ -11,7 +11,19 @@ import PrivacyPolicyRule, { RuleEvaluationResult } from './rules/PrivacyPolicyRu
 /**
  * Information about the reason this privacy policy is being evaluated.
  */
-export type EntityPrivacyPolicyEvaluationContext = {
+export type EntityPrivacyPolicyEvaluationContext<
+  TFields extends object,
+  TID extends NonNullable<TFields[TSelectedFields]>,
+  TViewerContext extends ViewerContext,
+  TEntity extends ReadonlyEntity<TFields, TID, TViewerContext, TSelectedFields>,
+  TSelectedFields extends keyof TFields = keyof TFields
+> = {
+  /**
+   * When this privacy policy is being evaluated as a result of an update, this will be populated with the value
+   * of the entity before the update. Note that this doesn't only apply to UPDATE authorization actions though:
+   * when an entity is updated it is re-LOADed after the update completes.
+   */
+  previousValue: TEntity | null;
   /**
    * When this privacy policy is being evaluated as a result of a cascading deletion, this will be populated
    * with information on the cascading delete.
@@ -154,7 +166,13 @@ export default abstract class EntityPrivacyPolicy<
   async authorizeCreateAsync(
     viewerContext: TViewerContext,
     queryContext: EntityQueryContext,
-    evaluationContext: EntityPrivacyPolicyEvaluationContext,
+    evaluationContext: EntityPrivacyPolicyEvaluationContext<
+      TFields,
+      TID,
+      TViewerContext,
+      TEntity,
+      TSelectedFields
+    >,
     entity: TEntity,
     metricsAdapter: IEntityMetricsAdapter
   ): Promise<TEntity> {
@@ -180,7 +198,13 @@ export default abstract class EntityPrivacyPolicy<
   async authorizeReadAsync(
     viewerContext: TViewerContext,
     queryContext: EntityQueryContext,
-    evaluationContext: EntityPrivacyPolicyEvaluationContext,
+    evaluationContext: EntityPrivacyPolicyEvaluationContext<
+      TFields,
+      TID,
+      TViewerContext,
+      TEntity,
+      TSelectedFields
+    >,
     entity: TEntity,
     metricsAdapter: IEntityMetricsAdapter
   ): Promise<TEntity> {
@@ -206,7 +230,13 @@ export default abstract class EntityPrivacyPolicy<
   async authorizeUpdateAsync(
     viewerContext: TViewerContext,
     queryContext: EntityQueryContext,
-    evaluationContext: EntityPrivacyPolicyEvaluationContext,
+    evaluationContext: EntityPrivacyPolicyEvaluationContext<
+      TFields,
+      TID,
+      TViewerContext,
+      TEntity,
+      TSelectedFields
+    >,
     entity: TEntity,
     metricsAdapter: IEntityMetricsAdapter
   ): Promise<TEntity> {
@@ -232,7 +262,13 @@ export default abstract class EntityPrivacyPolicy<
   async authorizeDeleteAsync(
     viewerContext: TViewerContext,
     queryContext: EntityQueryContext,
-    evaluationContext: EntityPrivacyPolicyEvaluationContext,
+    evaluationContext: EntityPrivacyPolicyEvaluationContext<
+      TFields,
+      TID,
+      TViewerContext,
+      TEntity,
+      TSelectedFields
+    >,
     entity: TEntity,
     metricsAdapter: IEntityMetricsAdapter
   ): Promise<TEntity> {
@@ -251,7 +287,13 @@ export default abstract class EntityPrivacyPolicy<
     ruleset: readonly PrivacyPolicyRule<TFields, TID, TViewerContext, TEntity, TSelectedFields>[],
     viewerContext: TViewerContext,
     queryContext: EntityQueryContext,
-    evaluationContext: EntityPrivacyPolicyEvaluationContext,
+    evaluationContext: EntityPrivacyPolicyEvaluationContext<
+      TFields,
+      TID,
+      TViewerContext,
+      TEntity,
+      TSelectedFields
+    >,
     entity: TEntity,
     action: EntityAuthorizationAction,
     metricsAdapter: IEntityMetricsAdapter
@@ -354,7 +396,13 @@ export default abstract class EntityPrivacyPolicy<
     ruleset: readonly PrivacyPolicyRule<TFields, TID, TViewerContext, TEntity, TSelectedFields>[],
     viewerContext: TViewerContext,
     queryContext: EntityQueryContext,
-    evaluationContext: EntityPrivacyPolicyEvaluationContext,
+    evaluationContext: EntityPrivacyPolicyEvaluationContext<
+      TFields,
+      TID,
+      TViewerContext,
+      TEntity,
+      TSelectedFields
+    >,
     entity: TEntity,
     action: EntityAuthorizationAction
   ): Promise<TEntity> {

packages/entity/src/ReadonlyEntity.ts

@@ -156,6 +156,6 @@ export default abstract class ReadonlyEntity<
     return viewerContext
       .getViewerScopedEntityCompanionForClass(this)
       .getLoaderFactory()
-      .forLoad(queryContext, { cascadingDeleteCause: null });
+      .forLoad(queryContext, { previousValue: null, cascadingDeleteCause: null });
   }
 }

packages/entity/src/ViewerScopedEntityLoaderFactory.ts

@@ -36,7 +36,13 @@ export default class ViewerScopedEntityLoaderFactory<
 
   forLoad(
     queryContext: EntityQueryContext,
-    privacyPolicyEvaluationContext: EntityPrivacyPolicyEvaluationContext
+    privacyPolicyEvaluationContext: EntityPrivacyPolicyEvaluationContext<
+      TFields,
+      TID,
+      TViewerContext,
+      TEntity,
+      TSelectedFields
+    >
   ): EntityLoader<TFields, TID, TViewerContext, TEntity, TPrivacyPolicy, TSelectedFields> {
     return this.entityLoaderFactory.forLoad(
       this.viewerContext,

packages/entity/src/__tests__/EntityCommonUseCases-test.ts

@@ -69,7 +69,12 @@ class DenyIfNotOwnerPrivacyPolicyRule extends PrivacyPolicyRule<
   async evaluateAsync(
     viewerContext: TestUserViewerContext,
     _queryContext: EntityQueryContext,
-    _evaluationContext: EntityPrivacyPolicyEvaluationContext,
+    _evaluationContext: EntityPrivacyPolicyEvaluationContext<
+      BlahFields,
+      string,
+      TestUserViewerContext,
+      BlahEntity
+    >,
     entity: BlahEntity
   ): Promise<RuleEvaluationResult> {
     if (viewerContext.getUserID() === entity.getField('ownerID')) {

packages/entity/src/__tests__/EntityEdges-test.ts

@@ -85,7 +85,13 @@ const makeEntityClasses = (edgeDeletionBehavior: EntityEdgeDeletionBehavior) =>
     async evaluateAsync(
       _viewerContext: TestViewerContext,
       _queryContext: EntityQueryContext,
-      evaluationContext: EntityPrivacyPolicyEvaluationContext,
+      evaluationContext: EntityPrivacyPolicyEvaluationContext<
+        any,
+        string,
+        TestViewerContext,
+        any,
+        any
+      >,
       entity: any
     ): Promise<RuleEvaluationResult> {
       if (privacyPolicyEvaluationRecords.shouldRecord) {

packages/entity/src/__tests__/EntityLoader-constructor-test.ts

@@ -121,7 +121,17 @@ export default class TestEntity extends Entity<
 describe(EntityLoader, () => {
   it('handles thrown errors and literals from constructor', async () => {
     const viewerContext = instance(mock(ViewerContext));
-    const privacyPolicyEvaluationContext = instance(mock<EntityPrivacyPolicyEvaluationContext>());
+    const privacyPolicyEvaluationContext = instance(
+      mock<
+        EntityPrivacyPolicyEvaluationContext<
+          TestFields,
+          string,
+          ViewerContext,
+          TestEntity,
+          TestFieldSelection
+        >
+      >()
+    );
     const metricsAdapter = instance(mock<IEntityMetricsAdapter>());
     const queryContext = StubQueryContextProvider.getQueryContext();