Lazily reference workflow in service construction

To prevent circular dependencies on initialization

Author: CarsonF

src/components/project/workflow/events/project-transitioned.event.ts

@@ -1,7 +1,7 @@
 import type { UnsecuredDto } from '~/common';
 import type { Project, ProjectStep } from '../../dto';
 import type { ProjectWorkflowEvent as WorkflowEvent } from '../dto';
-import { ProjectWorkflow } from '../project-workflow';
+import type { ProjectWorkflow } from '../project-workflow';
 
 export class ProjectTransitionedEvent {
   constructor(

src/components/project/workflow/project-workflow.flowchart.ts

@@ -4,5 +4,5 @@ import { ProjectWorkflow } from './project-workflow';
 
 @Injectable()
 export class ProjectWorkflowFlowchart extends WorkflowFlowchart(
-  ProjectWorkflow,
+  () => ProjectWorkflow,
 ) {}

src/components/project/workflow/project-workflow.granter.ts

@@ -5,7 +5,7 @@ import { ProjectWorkflow } from './project-workflow';
 
 @Granter(Event)
 export class ProjectWorkflowEventGranter extends WorkflowEventGranter(
-  ProjectWorkflow,
+  () => ProjectWorkflow,
 ) {}
 
 declare module '../../authorization/policy/granters' {

src/components/project/workflow/project-workflow.service.ts

@@ -16,7 +16,9 @@ import { ProjectWorkflow } from './project-workflow';
 import { ProjectWorkflowRepository } from './project-workflow.repository';
 
 @Injectable()
-export class ProjectWorkflowService extends WorkflowService(ProjectWorkflow) {
+export class ProjectWorkflowService extends WorkflowService(
+  () => ProjectWorkflow,
+) {
   constructor(
     private readonly resources: ResourceLoader,
     private readonly repo: ProjectWorkflowRepository,

src/components/workflow/workflow.flowchart.ts

@@ -12,8 +12,13 @@ import { deflateSync as deflate } from 'zlib';
 import { Workflow } from './define-workflow';
 import { DynamicState } from './transitions/dynamic-state';
 
-export const WorkflowFlowchart = <W extends Workflow>(workflow: W) => {
+export const WorkflowFlowchart = <W extends Workflow>(workflow: () => W) => {
   abstract class WorkflowFlowchartClass {
+    protected workflow: W;
+    constructor() {
+      this.workflow = workflow();
+    }
+
     /** Generate a flowchart in mermaid markup. */
     generateMarkup() {
       const rgbHexAddAlpha = (rgb: string, alpha: number) =>
@@ -46,12 +51,12 @@ export const WorkflowFlowchart = <W extends Workflow>(workflow: W) => {
         uuid.v1().replaceAll(/-/g, ''),
       );
 
-      const transitions = workflow.transitions
+      const transitions = this.workflow.transitions
         .toSorted(
           cmpBy((t) => {
             const endState =
               typeof t.to === 'string' ? t.to : t.to.relatedStates?.[0];
-            return workflow.states.entries.findIndex(
+            return this.workflow.states.entries.findIndex(
               (e) => e.value === endState,
             );
           }),
@@ -95,8 +100,8 @@ export const WorkflowFlowchart = <W extends Workflow>(workflow: W) => {
           .join('\n'),
       );
 
-      const stateLines = [...workflow.states].map((state) => {
-        const { label } = workflow.states.entry(state);
+      const stateLines = [...this.workflow.states].map((state) => {
+        const { label } = this.workflow.states.entry(state);
         const className = `${usedStates.has(state) ? '' : 'Unused'}State`;
         return `${state}(${label}):::${className}`;
       });

src/components/workflow/workflow.granter.ts

@@ -14,7 +14,7 @@ import { Workflow } from './define-workflow';
 export function WorkflowEventGranter<
   W extends Workflow,
   EventClass extends W['eventResource'],
->(workflow: W) {
+>(workflow: () => W) {
   type State = Workflow['state'];
   type Names = Workflow['transition']['name'];
 
@@ -37,7 +37,8 @@ export function WorkflowEventGranter<
      * Can read & execute all transitions.
      */
     get executeAll(): this {
-      return this.transitions(workflow.transitions.map((t) => t.name)).execute;
+      return this.transitions(workflow().transitions.map((t) => t.name))
+        .execute;
     }
 
     /**
@@ -48,15 +49,15 @@ export function WorkflowEventGranter<
     }
 
     isTransitions(...transitions: Array<Many<Names>>) {
-      return TransitionCondition.fromName(workflow, transitions.flat());
+      return TransitionCondition.fromName(workflow(), transitions.flat());
     }
 
     transitions(...transitions: Array<Many<Names>>) {
       return this.when(this.isTransitions(...transitions));
     }
 
     isState(...states: Array<Many<State>>) {
-      return TransitionCondition.fromEndState(workflow, states.flat());
+      return TransitionCondition.fromEndState(workflow(), states.flat());
     }
 
     state(...states: Array<Many<State>>) {

src/components/workflow/workflow.service.ts

@@ -14,11 +14,15 @@ type ExecuteTransitionInput = ReturnType<
   typeof ExecuteTransitionInputFn
 >['prototype'];
 
-export const WorkflowService = <W extends Workflow>(workflow: W) => {
+export const WorkflowService = <W extends Workflow>(workflow: () => W) => {
   @Injectable()
   abstract class WorkflowServiceClass {
     @Inject() protected readonly privileges: Privileges;
-    protected readonly workflow = workflow;
+    protected readonly workflow: W;
+
+    constructor() {
+      this.workflow = workflow();
+    }
 
     protected transitionByKey(key: ID | Nil, to: W['state']) {
       if (!key) {
@@ -45,7 +49,7 @@ export const WorkflowService = <W extends Workflow>(workflow: W) => {
       );
 
       // Filter out transitions without authorization to execute
-      const p = this.privileges.for(session, workflow.eventResource);
+      const p = this.privileges.for(session, this.workflow.eventResource);
       available = available.filter((t) =>
         // I don't have a good way to type this right now.
         // Context usage is still fuzzy when conditions need different shapes.
@@ -101,7 +105,9 @@ export const WorkflowService = <W extends Workflow>(workflow: W) => {
     }
 
     canBypass(session: Session) {
-      return this.privileges.for(session, workflow.eventResource).can('create');
+      return this.privileges
+        .for(session, this.workflow.eventResource)
+        .can('create');
     }
 
     protected getBypassIfValid(