Fix circular dependencies in migrator

src/di/Container.ts

@@ -1,4 +1,4 @@
-import {DependencyKey, InstanceRef, Instantiable, isInstantiable, StaticClass} from './types'
+import {DependencyKey, InstanceRef, Instantiable, isInstantiable, StaticClass, TypedDependencyKey} from './types'
 import {AbstractFactory} from './factory/AbstractFactory'
 import {collect, Collection, globalRegistry, logIfDebugging} from '../util'
 import {Factory} from './factory/Factory'
@@ -7,7 +7,7 @@ import {ClosureFactory} from './factory/ClosureFactory'
 import NamedFactory from './factory/NamedFactory'
 import SingletonFactory from './factory/SingletonFactory'
 import {InvalidDependencyKeyError} from './error/InvalidDependencyKeyError'
-import {ContainerBlueprint} from './ContainerBlueprint'
+import {ContainerBlueprint, ContainerResolutionCallback} from './ContainerBlueprint'
 
 export type MaybeFactory<T> = AbstractFactory<T> | undefined
 export type MaybeDependency = any | undefined
@@ -17,18 +17,36 @@ export type ResolvedDependency = { paramIndex: number, key: DependencyKey, resol
  * A container of resolve-able dependencies that are created via inversion-of-control.
  */
 export class Container {
+    /**
+     * Given a Container instance, apply the ContainerBlueprint to it.
+     * @param container
+     */
+    public static realizeContainer<T extends Container>(container: T): T {
+        ContainerBlueprint.getContainerBlueprint()
+            .resolve()
+            .map(factory => container.registerFactory(factory))
+
+        ContainerBlueprint.getContainerBlueprint()
+            .resolveConstructable()
+            .map((factory: StaticClass<AbstractFactory<any>, any>) => container.registerFactory(container.make(factory)))
+
+        ContainerBlueprint.getContainerBlueprint()
+            .resolveResolutionCallbacks()
+            .map((listener: {key: TypedDependencyKey<any>, callback: ContainerResolutionCallback<any>}) => {
+                container.onResolve(listener.key)
+                    .then(value => listener.callback(value))
+            })
+
+        return container
+    }
+
     /**
      * Get the global instance of this container.
      */
     public static getContainer(): Container {
         const existing = <Container | undefined> globalRegistry.getGlobal('extollo/injector')
         if ( !existing ) {
-            const container = new Container()
-
-            ContainerBlueprint.getContainerBlueprint()
-                .resolve()
-                .map(factory => container.registerFactory(factory))
-
+            const container = Container.realizeContainer(new Container())
             globalRegistry.setGlobal('extollo/injector', container)
             return container
         }
@@ -48,6 +66,12 @@ export class Container {
      */
     protected instances: Collection<InstanceRef> = new Collection<InstanceRef>()
 
+    /**
+     * Collection of callbacks waiting for a dependency key to be resolved.
+     * @protected
+     */
+    protected waitingResolveCallbacks: Collection<{ key: DependencyKey, callback: (t: unknown) => unknown }> = new Collection<{key: DependencyKey; callback:(t: unknown) => unknown}>();
+
     constructor() {
         this.registerSingletonInstance<Container>(Container, this)
         this.registerSingleton('injector', this)
@@ -172,6 +196,26 @@ export class Container {
         return this.instances.where('key', '=', key).isNotEmpty()
     }
 
+    /**
+     * Get a Promise that resolves the first time the given dependency key is resolved
+     * by the application. If it has already been resolved, the Promise will resolve immediately.
+     * @param key
+     */
+    onResolve<T>(key: TypedDependencyKey<T>): Promise<T> {
+        if ( this.hasInstance(key) ) {
+            return new Promise<T>(res => res(this.make<T>(key)))
+        }
+
+        // Otherwise, we haven't instantiated an instance with this key yet,
+        // so put it onto the waitlist.
+        return new Promise<T>(res => {
+            this.waitingResolveCallbacks.push({
+                key,
+                callback: (res as (t: unknown) => unknown),
+            })
+        })
+    }
+
     /**
      * Returns true if the container has a factory for the given key.
      * @param {DependencyKey} key
@@ -234,6 +278,15 @@ export class Container {
             value: newInstance,
         })
 
+        this.waitingResolveCallbacks = this.waitingResolveCallbacks.filter(waiter => {
+            if ( waiter.key === key ) {
+                waiter.callback(newInstance)
+                return false
+            }
+
+            return true
+        })
+
         return newInstance
     }
 

src/di/ContainerBlueprint.ts

@@ -1,9 +1,19 @@
-import {DependencyKey, Instantiable} from './types'
+import {DependencyKey, Instantiable, StaticClass, TypedDependencyKey} from './types'
 import NamedFactory from './factory/NamedFactory'
 import {AbstractFactory} from './factory/AbstractFactory'
 import {Factory} from './factory/Factory'
 import {ClosureFactory} from './factory/ClosureFactory'
 
+/** Simple type alias for a callback to a container's onResolve method. */
+export type ContainerResolutionCallback<T> = (() => unknown) | ((t: T) => unknown)
+
+/**
+ * Blueprint for newly-created containers.
+ *
+ * This is used to allow global helpers like `@Singleton()`
+ * or `@CLIDirective()` while still supporting multiple
+ * global Container instances at once.
+ */
 export class ContainerBlueprint {
     private static instance?: ContainerBlueprint
 
@@ -17,6 +27,19 @@ export class ContainerBlueprint {
 
     protected factories: (() => AbstractFactory<any>)[] = []
 
+    protected constructableFactories: StaticClass<AbstractFactory<any>, any>[] = []
+
+    protected resolutionCallbacks: ({key: TypedDependencyKey<any>, callback: ContainerResolutionCallback<any>})[] = []
+
+    /**
+     * Register some factory class with the container. Should take no construction params.
+     * @param factory
+     */
+    registerFactory(factory: StaticClass<AbstractFactory<any>, any>): this {
+        this.constructableFactories.push(factory)
+        return this
+    }
+
     /**
      * Register a basic instantiable class as a standard Factory with this container,
      * identified by a string name rather than static class.
@@ -47,7 +70,38 @@ export class ContainerBlueprint {
         return this
     }
 
+    /**
+     * Get an array of factory instances in the blueprint.
+     */
     resolve(): AbstractFactory<any>[] {
         return this.factories.map(x => x())
     }
+
+    /**
+     * Register an onResolve callback to be added to all newly-created containers.
+     * @param key
+     * @param callback
+     */
+    onResolve<T>(key: TypedDependencyKey<T>, callback: ContainerResolutionCallback<T>): this {
+        this.resolutionCallbacks.push({
+            key,
+            callback,
+        })
+        return this
+    }
+
+    /**
+     * Get an array of static Factory classes that need to be instantiated by
+     * the container itself.
+     */
+    resolveConstructable(): StaticClass<AbstractFactory<any>, any> {
+        return [...this.constructableFactories]
+    }
+
+    /**
+     * Get an array of DependencyKey-callback pairs to register with new containers.
+     */
+    resolveResolutionCallbacks(): ({key: TypedDependencyKey<any>, callback: ContainerResolutionCallback<any>})[] {
+        return [...this.resolutionCallbacks]
+    }
 }

src/di/decorator/injection.ts

@@ -1,5 +1,5 @@
 import 'reflect-metadata'
-import {collect, Collection} from '../../util'
+import {collect, Collection, logIfDebugging} from '../../util'
 import {
     DependencyKey,
     DependencyRequirement,
@@ -71,9 +71,10 @@ export const Injectable = (): ClassDecorator => {
  * If a `key` is specified, that DependencyKey will be injected.
  * Otherwise, the DependencyKey is inferred from the type annotation.
  * @param key
+ * @param debug
  * @constructor
  */
-export const Inject = (key?: DependencyKey): PropertyDecorator => {
+export const Inject = (key?: DependencyKey, { debug = false } = {}): PropertyDecorator => {
     return (target, property) => {
         let propertyMetadata = Reflect.getMetadata(DEPENDENCY_KEYS_PROPERTY_METADATA_KEY, target?.constructor || target) as Collection<PropertyDependency>
         if ( !propertyMetadata ) {
@@ -91,11 +92,18 @@ export const Inject = (key?: DependencyKey): PropertyDecorator => {
             if ( existing ) {
                 existing.key = key
             } else {
-                propertyMetadata.push({ property,
-                    key })
+                propertyMetadata.push({
+                    property,
+                    key,
+                    debug,
+                })
             }
         }
 
+        if ( debug ) {
+            logIfDebugging('extollo.di.decoration', '[DEBUG] @Inject() - key:', key, 'property:', property, 'target:', target, 'target constructor:', target?.constructor, 'type:', type)
+        }
+
         Reflect.defineMetadata(DEPENDENCY_KEYS_PROPERTY_METADATA_KEY, propertyMetadata, target?.constructor || target)
     }
 }
@@ -152,3 +160,15 @@ export const Singleton = (name?: string): ClassDecorator => {
         }
     }
 }
+
+/**
+ * Register a factory class directly with any created containers.
+ * @constructor
+ */
+export const FactoryProducer = (): ClassDecorator => {
+    return (target) => {
+        if ( isInstantiable(target) ) {
+            ContainerBlueprint.getContainerBlueprint().registerFactory(target)
+        }
+    }
+}

src/di/types.ts

@@ -23,6 +23,16 @@ export function isInstantiable<T>(what: unknown): what is Instantiable<T> {
     )
 }
 
+/**
+ * Returns true if the given value is instantiable and, once instantiated,
+ * will create an instance of the given static class.
+ * @param what
+ * @param type
+ */
+export function isInstantiableOf<T>(what: unknown, type: StaticClass<T, any>): what is Instantiable<T> {
+    return isInstantiable(what) && what.prototype instanceof type
+}
+
 /**
  * Type that identifies a value as a static class, even if it is not instantiable.
  */
@@ -41,6 +51,11 @@ export function isStaticClass<T, T2>(something: unknown): something is StaticCla
  */
 export type DependencyKey = Instantiable<any> | StaticClass<any, any> | string
 
+/**
+ * A DependencyKey, but typed
+ */
+export type TypedDependencyKey<T> = Instantiable<T> | StaticClass<T, any> | string
+
 /**
  * Interface used to store dependency requirements by their place in the injectable
  * target's parameters.
@@ -58,6 +73,7 @@ export interface DependencyRequirement {
 export interface PropertyDependency {
     key: DependencyKey,
     property: string | symbol,
+    debug?: boolean,
 }
 
 /**