fix(memoized-task): now canceled tasks are automatically retried

A canceled task could occur if your component is torn down before the
task completes. For long running tasks (such as those network-bound),
this can be a big problem, because the task will become cached, and
the next time a component is mounted that wants to access that same
network resource, no remote request would occur because the canceled
task was cached.

Now, canceled tasks bust the cache, allowing quick navigations or
quick remounts to correctly re-fetch network resources (or whatever
the long running async task is)

addon/-private/memoized-task.ts

@@ -2,6 +2,7 @@ import { Resource } from 'ember-could-get-used-to-this';
 import { action } from '@ember/object';
 import { assert } from '@ember/debug';
 import { getOwner } from '@ember/application';
+import { DEBUG } from '@glimmer/env';
 
 import { taskFor } from 'ember-concurrency-ts';
 import { task } from 'ember-concurrency-decorators';
@@ -21,6 +22,9 @@ interface Args<Return, TaskArgs extends CacheableArgs> {
 
 const CACHE = 'service:ember-resource-tasks/-private/do-not-use/arg-cache';
 
+export const TASK_PROPERTY = Symbol('TASK');
+export const TASK_INSTANCE_FROM_CACHE = Symbol('TASK_FROM_CACHE');
+
 /**
  * Whenever any args change *value*, the task will re run
  * All args must be stringish
@@ -45,15 +49,26 @@ export class MemoizedTask<Return, TaskArgs extends CacheableArgs> extends Resour
     consumeTag(task, 'isFinished');
     consumeTag(task, 'error');
 
-    return { ...extractTaskData(task), retry: this._perform };
+    let result = { ...extractTaskData(task), retry: this._perform };
+
+    if (DEBUG) {
+      (result as any)[TASK_INSTANCE_FROM_CACHE] = task;
+      (result as any)[TASK_PROPERTY] = task;
+    }
+
+    return result;
   }
 
   private get cacheKey() {
     return toCacheKey(...this.args.named.args);
   }
 
   private get needsUpdate() {
-    return !this.cacheBucket.has(this.cacheKey);
+    if (!this.cacheBucket.has(this.cacheKey)) {
+      return true;
+    }
+
+    return this.cacheBucket.get(this.cacheKey)?.isCanceled;
   }
 
   get _task() {

addon/tsconfig.json

@@ -6,6 +6,7 @@
     "paths": {
       "ember-resource-tasks": ["."],
       "ember-resource-tasks/*": ["./*"],
+      "@ember/destroyable": ["node_modules/ember-destroyable-polyfill"],
       "*": ["../types"]
     }
   },

package.json

@@ -67,6 +67,7 @@
     "ember-concurrency-decorators": "^2.0.3",
     "ember-concurrency-ts": "^0.2.2",
     "ember-could-get-used-to-this": "^1.0.1",
+    "ember-destroyable-polyfill": "^2.0.3",
     "ember-test-waiters": "^2.1.3"
   },
   "devDependencies": {

tests/integration/resources/memoized-task-test.ts

@@ -6,9 +6,11 @@ import { setupTest } from 'ember-qunit';
 import { setOwner } from '@ember/application';
 import { settled } from '@ember/test-helpers';
 import { waitFor } from '@ember/test-waiters';
+import { destroy } from '@ember/destroyable';
 
 import { MemoizedTask, valueFor } from 'ember-resource-tasks';
 import { consumeTag } from 'ember-resource-tasks/-private/utils';
+import { TASK_INSTANCE_FROM_CACHE } from 'ember-resource-tasks/-private/memoized-task';
 
 import type ApplicationInstance from '@ember/application/instance';
 
@@ -113,4 +115,33 @@ module('Integration | Resource | MemoizedTask', function (hooks) {
     assert.equal(subject2.data.value, 5, 'the cache bucket transfers to other instances');
     assert.equal(invocations, 3, 'value used is from cache and not recomputed');
   });
+
+  test(`a canceled task in the cache is ignored`, async function (assert) {
+    let subject = create(this.owner);
+
+    assert.equal(invocations, 0);
+    assert.equal(subject.data.value, undefined);
+
+    let taskInstance = (subject.data as any)[TASK_INSTANCE_FROM_CACHE];
+
+    destroy(subject);
+
+    await settled();
+
+    assert.equal(taskInstance.isCanceled, true, 'task is cancelled');
+    assert.equal(invocations, 1);
+
+    let subject2 = create(this.owner);
+
+    assert.equal(subject2.data.value, undefined);
+
+    await settled();
+
+    taskInstance = (subject2.data as any)[TASK_INSTANCE_FROM_CACHE];
+
+    assert.equal(taskInstance.isCanceled, false, 'task is not cancelled');
+
+    assert.equal(subject2.data.value, 1);
+    assert.equal(invocations, 2);
+  });
 });

yarn.lock

@@ -5385,7 +5385,7 @@ debug@~4.1.0:
   dependencies:
     ms "^2.1.1"
 
-debuglog@*, debuglog@^1.0.1:
+debuglog@^1.0.1:
   version "1.0.1"
   resolved "https://registry.npmjs.org/debuglog/-/debuglog-1.0.1.tgz#aa24ffb9ac3df9a2351837cfb2d279360cd78492"
   integrity sha1-qiT/uaw9+aI1GDfPstJ5NgzXhJI=
@@ -8392,7 +8392,7 @@ import-lazy@^2.1.0:
   resolved "https://registry.npmjs.org/import-lazy/-/import-lazy-2.1.0.tgz#05698e3d45c88e8d7e9d92cb0584e77f096f3e43"
   integrity sha1-BWmOPUXIjo1+nZLLBYTnfwlvPkM=
 
-imurmurhash@*, imurmurhash@^0.1.4:
+imurmurhash@^0.1.4:
   version "0.1.4"
   resolved "https://registry.npmjs.org/imurmurhash/-/imurmurhash-0.1.4.tgz#9218b9b2b928a238b13dc4fb6b6d576f231453ea"
   integrity sha1-khi5srkoojixPcT7a21XbyMUU+o=
@@ -9575,11 +9575,6 @@ lodash._baseflatten@^3.0.0:
     lodash.isarguments "^3.0.0"
     lodash.isarray "^3.0.0"
 
-lodash._baseindexof@*:
-  version "3.1.0"
-  resolved "https://registry.npmjs.org/lodash._baseindexof/-/lodash._baseindexof-3.1.0.tgz#fe52b53a1c6761e42618d654e4a25789ed61822c"
-  integrity sha1-/lK1OhxnYeQmGNZU5KJXie1hgiw=
-
 lodash._baseuniq@~4.6.0:
   version "4.6.0"
   resolved "https://registry.npmjs.org/lodash._baseuniq/-/lodash._baseuniq-4.6.0.tgz#0ebb44e456814af7905c6212fa2c9b2d51b841e8"
@@ -9588,16 +9583,11 @@ lodash._baseuniq@~4.6.0:
     lodash._createset "~4.0.0"
     lodash._root "~3.0.0"
 
-lodash._bindcallback@*, lodash._bindcallback@^3.0.0:
+lodash._bindcallback@^3.0.0:
   version "3.0.1"
   resolved "https://registry.npmjs.org/lodash._bindcallback/-/lodash._bindcallback-3.0.1.tgz#e531c27644cf8b57a99e17ed95b35c748789392e"
   integrity sha1-5THCdkTPi1epnhftlbNcdIeJOS4=
 
-lodash._cacheindexof@*:
-  version "3.0.2"
-  resolved "https://registry.npmjs.org/lodash._cacheindexof/-/lodash._cacheindexof-3.0.2.tgz#3dc69ac82498d2ee5e3ce56091bafd2adc7bde92"
-  integrity sha1-PcaayCSY0u5ePOVgkbr9Ktx73pI=
-
 lodash._createassigner@^3.0.0:
   version "3.1.1"
   resolved "https://registry.npmjs.org/lodash._createassigner/-/lodash._createassigner-3.1.1.tgz#838a5bae2fdaca63ac22dee8e19fa4e6d6970b11"
@@ -9607,19 +9597,12 @@ lodash._createassigner@^3.0.0:
     lodash._isiterateecall "^3.0.0"
     lodash.restparam "^3.0.0"
 
-lodash._createcache@*:
-  version "3.1.2"
-  resolved "https://registry.npmjs.org/lodash._createcache/-/lodash._createcache-3.1.2.tgz#56d6a064017625e79ebca6b8018e17440bdcf093"
-  integrity sha1-VtagZAF2JeeevKa4AY4XRAvc8JM=
-  dependencies:
-    lodash._getnative "^3.0.0"
-
 lodash._createset@~4.0.0:
   version "4.0.3"
   resolved "https://registry.npmjs.org/lodash._createset/-/lodash._createset-4.0.3.tgz#0f4659fbb09d75194fa9e2b88a6644d363c9fe26"
   integrity sha1-D0ZZ+7CddRlPqeK4imZE02PJ/iY=
 
-lodash._getnative@*, lodash._getnative@^3.0.0:
+lodash._getnative@^3.0.0:
   version "3.9.1"
   resolved "https://registry.npmjs.org/lodash._getnative/-/lodash._getnative-3.9.1.tgz#570bc7dede46d61cdcde687d65d3eecbaa3aaff5"
   integrity sha1-VwvH3t5G1hzc3mh9ZdPuy6o6r/U=
@@ -9757,7 +9740,7 @@ lodash.omit@^4.1.0:
   resolved "https://registry.npmjs.org/lodash.omit/-/lodash.omit-4.5.0.tgz#6eb19ae5a1ee1dd9df0b969e66ce0b7fa30b5e60"
   integrity sha1-brGa5aHuHdnfC5aeZs4Lf6MLXmA=
 
-lodash.restparam@*, lodash.restparam@^3.0.0:
+lodash.restparam@^3.0.0:
   version "3.6.1"
   resolved "https://registry.npmjs.org/lodash.restparam/-/lodash.restparam-3.6.1.tgz#936a4e309ef330a7645ed4145986c85ae5b20805"
   integrity sha1-k2pOMJ7zMKdkXtQUWYbIWuWyCAU=