Allow context modification in optimize-query-operation bus

packages/actor-init-sparql/lib/ActorInitSparql-browser.ts

@@ -199,7 +199,9 @@ export class ActorInitSparql extends ActorInit implements IActorInitSparqlArgs,
     }
 
     // Optimize the query operation
-    operation = (await this.mediatorOptimizeQueryOperation.mediate({ context, operation })).operation;
+    const mediatorResult = await this.mediatorOptimizeQueryOperation.mediate({ context, operation });
+    operation = mediatorResult.operation;
+    context = mediatorResult.context || context;
 
     // Pre-processing the context, this time with the operation
     context = (await this.mediatorContextPreprocess.mediate({ context, operation })).context;

packages/actor-init-sparql/test/ActorInitSparql-test.ts

@@ -621,6 +621,27 @@ describe('ActorInitSparql', () => {
             '@comunica/actor-init-sparql:baseIRI': 'myBaseIRI',
           });
       });
+
+      it('should pass down the provided context if optimize actors do not return one', async() => {
+        mediatorOptimizeQueryOperation.mediate = (action: any) => {
+          return Promise.resolve({ ...action, context: undefined });
+        };
+        const result = await actor.query('SELECT * WHERE { ?s ?p ?o }', { 'the-answer': 42 });
+        expect(result).toHaveProperty('context');
+        expect(result.context!.get('the-answer')).toEqual(42);
+      });
+
+      it('should allow optimize actors to modify the context', async() => {
+        mediatorOptimizeQueryOperation.mediate = (action: any) => {
+          return Promise.resolve({
+            ...action,
+            context: action.context.set('the-answer', 42),
+          });
+        };
+        const result = await actor.query('SELECT * WHERE { ?s ?p ?o }');
+        expect(result).toHaveProperty('context');
+        expect(result.context!.get('the-answer')).toEqual(42);
+      });
     });
 
     it('bindings() should collect all bindings until "end" event occurs on triples', async() => {

packages/bus-http-invalidate/lib/ActorHttpInvalidateListenable.ts

@@ -27,7 +27,7 @@ export class ActorHttpInvalidateListenable extends ActorHttpInvalidate {
     for (const listener of this.invalidateListeners) {
       listener(action);
     }
-    return true;
+    return {};
   }
 }
 

packages/bus-optimize-query-operation/lib/ActorOptimizeQueryOperation.ts

@@ -1,5 +1,6 @@
 import type { IAction, IActorArgs, IActorOutput, IActorTest } from '@comunica/core';
 import { Actor } from '@comunica/core';
+import type { ActionContext } from '@comunica/types';
 import type { Algebra } from 'sparqlalgebrajs';
 
 /**
@@ -26,4 +27,5 @@ export interface IActionOptimizeQueryOperation extends IAction {
 
 export interface IActorOptimizeQueryOperationOutput extends IActorOutput {
   operation: Algebra.Operation;
+  context?: ActionContext;
 }

packages/bus-optimize-query-operation/package.json

@@ -31,6 +31,7 @@
     "index.js"
   ],
   "dependencies": {
+    "@comunica/types": "^1.20.0",
     "sparqlalgebrajs": "^2.5.5"
   },
   "peerDependencies": {

packages/mediator-combine-pipeline/lib/MediatorCombinePipeline.ts

@@ -27,7 +27,7 @@ export class MediatorCombinePipeline<A extends Actor<H, T, H>, H extends IAction
     // and each actor output as input to the following actor.
     let handle: H = action;
     for (const actor of testResults.map(result => result.actor)) {
-      handle = await actor.runObservable(handle);
+      handle = { ...handle, ...await actor.runObservable(handle) };
     }
 
     // Return the final actor output

packages/mediator-combine-pipeline/test/MediatorCombinePipeline-test.ts

@@ -1,5 +1,5 @@
 import type { IAction, IActorOutput, IActorTest } from '@comunica/core';
-import { Actor, Bus, Mediator } from '@comunica/core';
+import { Actor, Bus, Mediator, ActionContext } from '@comunica/core';
 import { MediatorCombinePipeline } from '../lib/MediatorCombinePipeline';
 
 describe('MediatorCombinePipeline', () => {
@@ -39,6 +39,21 @@ describe('MediatorCombinePipeline', () => {
     it('should mediate', () => {
       return expect(mediator.mediate({ field: 1 })).resolves.toEqual({ field: 2_101 });
     });
+
+    it('should mediate without changing the context', async() => {
+      const context = ActionContext({});
+      const result = await mediator.mediate({ field: 1, context });
+      expect(result).toEqual({ field: 2_101, context });
+    });
+
+    it('should mediate changing the context', async() => {
+      new DummyActorContextOutput(1_000, bus);
+      const context = ActionContext({});
+      const result = await mediator.mediate({ field: 1, context });
+      expect(result).toHaveProperty('context');
+      expect(result.context).not.toEqual(context);
+      expect(result.context!.get('id')).toEqual(1_000);
+    });
   });
 
   describe('An MediatorCombinePipeline instance without actors', () => {
@@ -54,10 +69,10 @@ describe('MediatorCombinePipeline', () => {
   });
 });
 
-class DummyActor extends Actor<IDummyAction, IActorTest, IDummyAction> {
+class DummyActor extends Actor<IDummyAction, IActorTest, IDummyOutput> {
   public readonly id: number;
 
-  public constructor(id: number, bus: Bus<DummyActor, IDummyAction, IActorTest, IDummyAction>) {
+  public constructor(id: number, bus: Bus<DummyActor, IDummyAction, IActorTest, IDummyOutput>) {
     super({ name: `dummy${id}`, bus });
     this.id = id;
   }
@@ -66,11 +81,25 @@ class DummyActor extends Actor<IDummyAction, IActorTest, IDummyAction> {
     return true;
   }
 
-  public async run(action: IDummyAction): Promise<IDummyAction> {
+  public async run(action: IDummyAction): Promise<IDummyOutput> {
     return { field: action.field * this.id + this.id };
   }
 }
 
-interface IDummyAction extends IAction, IActorOutput {
+class DummyActorContextOutput extends DummyActor {
+  public async run(action: IDummyAction): Promise<IDummyOutput> {
+    return {
+      ...super.run(action),
+      context: (action.context || ActionContext({})).set('id', this.id),
+    };
+  }
+}
+
+interface IDummyAction extends IAction {
+  field: number;
+}
+
+interface IDummyOutput extends IActorOutput {
   field: number;
+  context?: ActionContext;
 }